| 49 |
|
* are typically useful only when a map is not undergoing concurrent |
| 50 |
|
* updates in other threads. Otherwise the results of these methods |
| 51 |
|
* reflect transient states that may be adequate for monitoring |
| 52 |
< |
* purposes, but not for program control. |
| 52 |
> |
* or estimation purposes, but not for program control. |
| 53 |
|
* |
| 54 |
< |
* <p> Resizing this or any other kind of hash table is a relatively |
| 55 |
< |
* slow operation, so, when possible, it is a good idea to provide |
| 56 |
< |
* estimates of expected table sizes in constructors. Also, for |
| 57 |
< |
* compatibility with previous versions of this class, constructors |
| 58 |
< |
* may optionally specify an expected {@code concurrencyLevel} as an |
| 59 |
< |
* additional hint for internal sizing. |
| 54 |
> |
* <p> The table is dynamically expanded when there are too many |
| 55 |
> |
* collisions (i.e., keys that have distinct hash codes but fall into |
| 56 |
> |
* the same slot modulo the table size), with the expected average |
| 57 |
> |
* effect of maintaining roughly two bins per mapping. There may be |
| 58 |
> |
* much variance around this average as mappings are added and |
| 59 |
> |
* removed, but overall, this maintains a commonly accepted time/space |
| 60 |
> |
* tradeoff for hash tables. However, resizing this or any other kind |
| 61 |
> |
* of hash table may be a relatively slow operation. When possible, it |
| 62 |
> |
* is a good idea to provide a size estimate as an optional {@code |
| 63 |
> |
* initialCapacity} constructor argument. An additional optional |
| 64 |
> |
* {@code loadFactor} constructor argument provides a further means of |
| 65 |
> |
* customizing initial table capacity by specifying the table density |
| 66 |
> |
* to be used in calculating the amount of space to allocate for the |
| 67 |
> |
* given number of elements. Also, for compatibility with previous |
| 68 |
> |
* versions of this class, constructors may optionally specify an |
| 69 |
> |
* expected {@code concurrencyLevel} as an additional hint for |
| 70 |
> |
* internal sizing. Note that using many keys with exactly the same |
| 71 |
> |
* {@code hashCode{}} is a sure way to slow down performance of any |
| 72 |
> |
* hash table. |
| 73 |
|
* |
| 74 |
|
* <p>This class and its views and iterators implement all of the |
| 75 |
|
* <em>optional</em> methods of the {@link Map} and {@link Iterator} |
| 126 |
|
* Each key-value mapping is held in a Node. Because Node fields |
| 127 |
|
* can contain special values, they are defined using plain Object |
| 128 |
|
* types. Similarly in turn, all internal methods that use them |
| 129 |
< |
* work off Object types. All public generic-typed methods relay |
| 130 |
< |
* in/out of these internal methods, supplying casts as needed. |
| 129 |
> |
* work off Object types. And similarly, so do the internal |
| 130 |
> |
* methods of auxiliary iterator and view classes. All public |
| 131 |
> |
* generic typed methods relay in/out of these internal methods, |
| 132 |
> |
* supplying null-checks and casts as needed. |
| 133 |
|
* |
| 134 |
|
* The table is lazily initialized to a power-of-two size upon the |
| 135 |
< |
* first insertion. Each bin in the table contains a (typically |
| 136 |
< |
* short) list of Nodes. Table accesses require volatile/atomic |
| 137 |
< |
* reads, writes, and CASes. Because there is no other way to |
| 138 |
< |
* arrange this without adding further indirections, we use |
| 139 |
< |
* intrinsics (sun.misc.Unsafe) operations. The lists of nodes |
| 140 |
< |
* within bins are always accurately traversable under volatile |
| 141 |
< |
* reads, so long as lookups check hash code and non-nullness of |
| 142 |
< |
* key and value before checking key equality. (All valid hash |
| 143 |
< |
* codes are nonnegative. Negative values are reserved for special |
| 144 |
< |
* forwarding nodes; see below.) |
| 145 |
< |
* |
| 146 |
< |
* A bin may be locked during update (insert, delete, and replace) |
| 147 |
< |
* operations. We do not want to waste the space required to |
| 148 |
< |
* associate a distinct lock object with each bin, so instead use |
| 149 |
< |
* the first node of a bin list itself as a lock, using builtin |
| 150 |
< |
* "synchronized" locks. These save space and we can live with |
| 151 |
< |
* only plain block-structured lock/unlock operations. Using the |
| 152 |
< |
* first node of a list as a lock does not by itself suffice |
| 153 |
< |
* though: When a node is locked, any update must first validate |
| 154 |
< |
* that it is still the first node, and retry if not. (Because new |
| 155 |
< |
* nodes are always appended to lists, once a node is first in a |
| 156 |
< |
* bin, it remains first until deleted or the bin becomes |
| 157 |
< |
* invalidated.) However, update operations can and usually do |
| 158 |
< |
* still traverse the bin until the point of update, which helps |
| 159 |
< |
* reduce cache misses on retries. This is a converse of sorts to |
| 160 |
< |
* the lazy locking technique described by Herlihy & Shavit. If |
| 161 |
< |
* there is no existing node during a put operation, then one can |
| 162 |
< |
* be CAS'ed in (without need for lock except in computeIfAbsent); |
| 163 |
< |
* the CAS serves as validation. This is on average the most |
| 164 |
< |
* common case for put operations -- under random hash codes, the |
| 165 |
< |
* distribution of nodes in bins follows a Poisson distribution |
| 166 |
< |
* (see http://en.wikipedia.org/wiki/Poisson_distribution) with a |
| 167 |
< |
* parameter of 0.5 on average under the default loadFactor of |
| 168 |
< |
* 0.75. The expected number of locks covering different elements |
| 169 |
< |
* (i.e., bins with 2 or more nodes) is approximately 10% at |
| 170 |
< |
* steady state under default settings. Lock contention |
| 171 |
< |
* probability for two threads accessing arbitrary distinct |
| 172 |
< |
* elements is, roughly, 1 / (8 * #elements). |
| 135 |
> |
* first insertion. Each bin in the table contains a list of |
| 136 |
> |
* Nodes (most often, zero or one Node). Table accesses require |
| 137 |
> |
* volatile/atomic reads, writes, and CASes. Because there is no |
| 138 |
> |
* other way to arrange this without adding further indirections, |
| 139 |
> |
* we use intrinsics (sun.misc.Unsafe) operations. The lists of |
| 140 |
> |
* nodes within bins are always accurately traversable under |
| 141 |
> |
* volatile reads, so long as lookups check hash code and |
| 142 |
> |
* non-nullness of value before checking key equality. (All valid |
| 143 |
> |
* hash codes are nonnegative. Negative values are reserved for |
| 144 |
> |
* special forwarding nodes; see below.) |
| 145 |
> |
* |
| 146 |
> |
* Insertion (via put or putIfAbsent) of the first node in an |
| 147 |
> |
* empty bin is performed by just CASing it to the bin. This is |
| 148 |
> |
* on average by far the most common case for put operations. |
| 149 |
> |
* Other update operations (insert, delete, and replace) require |
| 150 |
> |
* locks. We do not want to waste the space required to associate |
| 151 |
> |
* a distinct lock object with each bin, so instead use the first |
| 152 |
> |
* node of a bin list itself as a lock, using plain "synchronized" |
| 153 |
> |
* locks. These save space and we can live with block-structured |
| 154 |
> |
* lock/unlock operations. Using the first node of a list as a |
| 155 |
> |
* lock does not by itself suffice though: When a node is locked, |
| 156 |
> |
* any update must first validate that it is still the first node, |
| 157 |
> |
* and retry if not. Because new nodes are always appended to |
| 158 |
> |
* lists, once a node is first in a bin, it remains first until |
| 159 |
> |
* deleted or the bin becomes invalidated. However, operations |
| 160 |
> |
* that only conditionally update can and sometimes do inspect |
| 161 |
> |
* nodes until the point of update. This is a converse of sorts to |
| 162 |
> |
* the lazy locking technique described by Herlihy & Shavit. |
| 163 |
> |
* |
| 164 |
> |
* The main disadvantage of this approach is that most update |
| 165 |
> |
* operations on other nodes in a bin list protected by the same |
| 166 |
> |
* lock can stall, for example when user equals() or mapping |
| 167 |
> |
* functions take a long time. However, statistically, this is |
| 168 |
> |
* not a common enough problem to outweigh the time/space overhead |
| 169 |
> |
* of alternatives: Under random hash codes, the frequency of |
| 170 |
> |
* nodes in bins follows a Poisson distribution |
| 171 |
> |
* (http://en.wikipedia.org/wiki/Poisson_distribution) with a |
| 172 |
> |
* parameter of about 0.5 on average, given the resizing threshold |
| 173 |
> |
* of 0.75, although with a large variance because of resizing |
| 174 |
> |
* granularity. Ignoring variance, the expected occurrences of |
| 175 |
> |
* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The |
| 176 |
> |
* first few values are: |
| 177 |
> |
* |
| 178 |
> |
* 0: 0.607 |
| 179 |
> |
* 1: 0.303 |
| 180 |
> |
* 2: 0.076 |
| 181 |
> |
* 3: 0.012 |
| 182 |
> |
* more: 0.002 |
| 183 |
> |
* |
| 184 |
> |
* Lock contention probability for two threads accessing distinct |
| 185 |
> |
* elements is roughly 1 / (8 * #elements). Function "spread" |
| 186 |
> |
* performs hashCode randomization that improves the likelihood |
| 187 |
> |
* that these assumptions hold unless users define exactly the |
| 188 |
> |
* same value for too many hashCodes. |
| 189 |
|
* |
| 190 |
|
* The table is resized when occupancy exceeds a threshold. Only |
| 191 |
|
* a single thread performs the resize (using field "resizing", to |
| 192 |
|
* arrange exclusion), but the table otherwise remains usable for |
| 193 |
< |
* both reads and updates. Resizing proceeds by transferring bins, |
| 194 |
< |
* one by one, from the table to the next table. Upon transfer, |
| 195 |
< |
* the old table bin contains only a special forwarding node (with |
| 196 |
< |
* negative hash code ("MOVED")) that contains the next table as |
| 197 |
< |
* its key. On encountering a forwarding node, access and update |
| 193 |
> |
* reads and updates. Resizing proceeds by transferring bins, one |
| 194 |
> |
* by one, from the table to the next table. Upon transfer, the |
| 195 |
> |
* old table bin contains only a special forwarding node (with |
| 196 |
> |
* negative hash field) that contains the next table as its |
| 197 |
> |
* key. On encountering a forwarding node, access and update |
| 198 |
|
* operations restart, using the new table. To ensure concurrent |
| 199 |
|
* readability of traversals, transfers must proceed from the last |
| 200 |
< |
* bin (table.length - 1) up towards the first. Any traversal |
| 201 |
< |
* starting from the first bin can then arrange to move to the new |
| 202 |
< |
* table for the rest of the traversal without revisiting nodes. |
| 203 |
< |
* This constrains bin transfers to a particular order, and so can |
| 204 |
< |
* block indefinitely waiting for the next lock, and other threads |
| 205 |
< |
* cannot help with the transfer. However, expected stalls are |
| 206 |
< |
* infrequent enough to not warrant the additional overhead and |
| 207 |
< |
* complexity of access and iteration schemes that could admit |
| 208 |
< |
* out-of-order or concurrent bin transfers. |
| 209 |
< |
* |
| 210 |
< |
* A similar traversal scheme (not yet implemented) can apply to |
| 211 |
< |
* partial traversals during partitioned aggregate operations. |
| 212 |
< |
* Also, read-only operations give up if ever forwarded to a null |
| 213 |
< |
* table, which provides support for shutdown-style clearing, |
| 214 |
< |
* which is also not currently implemented. |
| 200 |
> |
* bin (table.length - 1) up towards the first. Upon seeing a |
| 201 |
> |
* forwarding node, traversals (see class InternalIterator) |
| 202 |
> |
* arrange to move to the new table for the rest of the traversal |
| 203 |
> |
* without revisiting nodes. This constrains bin transfers to a |
| 204 |
> |
* particular order, and so can block indefinitely waiting for the |
| 205 |
> |
* next lock, and other threads cannot help with the transfer. |
| 206 |
> |
* However, expected stalls are infrequent enough to not warrant |
| 207 |
> |
* the additional overhead of access and iteration schemes that |
| 208 |
> |
* could admit out-of-order or concurrent bin transfers. |
| 209 |
> |
* |
| 210 |
> |
* This traversal scheme also applies to partial traversals of |
| 211 |
> |
* ranges of bins (via an alternate InternalIterator constructor) |
| 212 |
> |
* to support partitioned aggregate operations (that are not |
| 213 |
> |
* otherwise implemented yet). Also, read-only operations give up |
| 214 |
> |
* if ever forwarded to a null table, which provides support for |
| 215 |
> |
* shutdown-style clearing, which is also not currently |
| 216 |
> |
* implemented. |
| 217 |
> |
* |
| 218 |
> |
* Lazy table initialization minimizes footprint until first use, |
| 219 |
> |
* and also avoids resizings when the first operation is from a |
| 220 |
> |
* putAll, constructor with map argument, or deserialization. |
| 221 |
> |
* These cases attempt to override the targetCapacity used in |
| 222 |
> |
* growTable. These harmlessly fail to take effect in cases of |
| 223 |
> |
* races with other ongoing resizings. Uses of the threshold and |
| 224 |
> |
* targetCapacity during attempted initializations or resizings |
| 225 |
> |
* are racy but fall back on checks to preserve correctness. |
| 226 |
|
* |
| 227 |
|
* The element count is maintained using a LongAdder, which avoids |
| 228 |
|
* contention on updates but can encounter cache thrashing if read |
| 229 |
< |
* too frequently during concurrent updates. To avoid reading so |
| 229 |
> |
* too frequently during concurrent access. To avoid reading so |
| 230 |
|
* often, resizing is normally attempted only upon adding to a bin |
| 231 |
< |
* already holding two or more nodes. Under the default threshold |
| 232 |
< |
* (0.75), and uniform hash distributions, the probability of this |
| 233 |
< |
* occurring at threshold is around 13%, meaning that only about 1 |
| 234 |
< |
* in 8 puts check threshold (and after resizing, many fewer do |
| 235 |
< |
* so). But this approximation has high variance for small table |
| 236 |
< |
* sizes, so we check on any collision for sizes <= 64. Further, |
| 237 |
< |
* to increase the probability that a resize occurs soon enough, we |
| 238 |
< |
* offset the threshold (see THRESHOLD_OFFSET) by the expected |
| 239 |
< |
* number of puts between checks. This is currently set to 8, in |
| 240 |
< |
* accord with the default load factor. In practice, this is |
| 241 |
< |
* rarely overridden, and in any case is close enough to other |
| 242 |
< |
* plausible values not to waste dynamic probability computation |
| 243 |
< |
* for more precision. |
| 231 |
> |
* already holding two or more nodes. Under uniform hash |
| 232 |
> |
* distributions, the probability of this occurring at threshold |
| 233 |
> |
* is around 13%, meaning that only about 1 in 8 puts check |
| 234 |
> |
* threshold (and after resizing, many fewer do so). But this |
| 235 |
> |
* approximation has high variance for small table sizes, so we |
| 236 |
> |
* check on any collision for sizes <= 64. Further, to increase |
| 237 |
> |
* the probability that a resize occurs soon enough, we offset the |
| 238 |
> |
* threshold (see THRESHOLD_OFFSET) by the expected number of puts |
| 239 |
> |
* between checks. |
| 240 |
> |
* |
| 241 |
> |
* Maintaining API and serialization compatibility with previous |
| 242 |
> |
* versions of this class introduces several oddities. Mainly: We |
| 243 |
> |
* leave untouched but unused constructor arguments refering to |
| 244 |
> |
* concurrencyLevel. We also declare an unused "Segment" class |
| 245 |
> |
* that is instantiated in minimal form only when serializing. |
| 246 |
|
*/ |
| 247 |
|
|
| 248 |
|
/* ---------------- Constants -------------- */ |
| 249 |
|
|
| 250 |
|
/** |
| 251 |
< |
* The smallest allowed table capacity. Must be a power of 2, at |
| 252 |
< |
* least 2. |
| 251 |
> |
* The largest possible table capacity. This value must be |
| 252 |
> |
* exactly 1<<30 to stay within Java array allocation and indexing |
| 253 |
> |
* bounds for power of two table sizes. |
| 254 |
|
*/ |
| 255 |
< |
static final int MINIMUM_CAPACITY = 2; |
| 255 |
> |
private static final int MAXIMUM_CAPACITY = 1 << 30; |
| 256 |
|
|
| 257 |
|
/** |
| 258 |
< |
* The largest allowed table capacity. Must be a power of 2, at |
| 259 |
< |
* most 1<<30. |
| 258 |
> |
* The default initial table capacity. Must be a power of 2 |
| 259 |
> |
* (i.e., at least 1) and at most MAXIMUM_CAPACITY. |
| 260 |
|
*/ |
| 261 |
< |
static final int MAXIMUM_CAPACITY = 1 << 30; |
| 261 |
> |
private static final int DEFAULT_CAPACITY = 16; |
| 262 |
|
|
| 263 |
|
/** |
| 264 |
< |
* The default initial table capacity. Must be a power of 2, at |
| 265 |
< |
* least MINIMUM_CAPACITY and at most MAXIMUM_CAPACITY |
| 264 |
> |
* The load factor for this table. Overrides of this value in |
| 265 |
> |
* constructors affect only the initial table capacity. The |
| 266 |
> |
* actual floating point value isn't normally used, because it is |
| 267 |
> |
* simpler to rely on the expression {@code n - (n >>> 2)} for the |
| 268 |
> |
* associated resizing threshold. |
| 269 |
|
*/ |
| 270 |
< |
static final int DEFAULT_CAPACITY = 16; |
| 270 |
> |
private static final float LOAD_FACTOR = 0.75f; |
| 271 |
|
|
| 272 |
|
/** |
| 273 |
< |
* The default load factor for this table, used when not otherwise |
| 274 |
< |
* specified in a constructor. |
| 273 |
> |
* The count value to offset thresholds to compensate for checking |
| 274 |
> |
* for the need to resize only when inserting into bins with two |
| 275 |
> |
* or more elements. See above for explanation. |
| 276 |
|
*/ |
| 277 |
< |
static final float DEFAULT_LOAD_FACTOR = 0.75f; |
| 277 |
> |
private static final int THRESHOLD_OFFSET = 8; |
| 278 |
|
|
| 279 |
|
/** |
| 280 |
< |
* The default concurrency level for this table. Unused, but |
| 281 |
< |
* defined for compatibility with previous versions of this class. |
| 280 |
> |
* The default concurrency level for this table. Unused except as |
| 281 |
> |
* a sizing hint, but defined for compatibility with previous |
| 282 |
> |
* versions of this class. |
| 283 |
|
*/ |
| 284 |
< |
static final int DEFAULT_CONCURRENCY_LEVEL = 16; |
| 284 |
> |
private static final int DEFAULT_CONCURRENCY_LEVEL = 16; |
| 285 |
> |
|
| 286 |
> |
/* ---------------- Nodes -------------- */ |
| 287 |
|
|
| 288 |
|
/** |
| 289 |
< |
* The count value to offset thresholds to compensate for checking |
| 290 |
< |
* for resizing only when inserting into bins with two or more |
| 291 |
< |
* elements. See above for explanation. |
| 289 |
> |
* Key-value entry. Note that this is never exported out as a |
| 290 |
> |
* user-visible Map.Entry. Nodes with a negative hash field are |
| 291 |
> |
* special, and do not contain user keys or values. Otherwise, |
| 292 |
> |
* keys are never null, and null val fields indicate that a node |
| 293 |
> |
* is in the process of being deleted or created. For purposes of |
| 294 |
> |
* read-only, access, a key may be read before a val, but can only |
| 295 |
> |
* be used after checking val. (For an update operation, when a |
| 296 |
> |
* lock is held on a node, order doesn't matter.) |
| 297 |
|
*/ |
| 298 |
< |
static final int THRESHOLD_OFFSET = 8; |
| 298 |
> |
static final class Node { |
| 299 |
> |
final int hash; |
| 300 |
> |
final Object key; |
| 301 |
> |
volatile Object val; |
| 302 |
> |
volatile Node next; |
| 303 |
> |
|
| 304 |
> |
Node(int hash, Object key, Object val, Node next) { |
| 305 |
> |
this.hash = hash; |
| 306 |
> |
this.key = key; |
| 307 |
> |
this.val = val; |
| 308 |
> |
this.next = next; |
| 309 |
> |
} |
| 310 |
> |
} |
| 311 |
|
|
| 312 |
|
/** |
| 313 |
< |
* Special node hash value indicating to use table in node.key |
| 245 |
< |
* Must be negative. |
| 313 |
> |
* Sign bit of node hash value indicating to use table in node.key. |
| 314 |
|
*/ |
| 315 |
< |
static final int MOVED = -1; |
| 315 |
> |
private static final int SIGN_BIT = 0x80000000; |
| 316 |
|
|
| 317 |
|
/* ---------------- Fields -------------- */ |
| 318 |
|
|
| 319 |
|
/** |
| 320 |
|
* The array of bins. Lazily initialized upon first insertion. |
| 321 |
< |
* Size is always a power of two. Accessed directly by inner |
| 254 |
< |
* classes. |
| 321 |
> |
* Size is always a power of two. Accessed directly by iterators. |
| 322 |
|
*/ |
| 323 |
|
transient volatile Node[] table; |
| 324 |
|
|
| 326 |
|
private transient final LongAdder counter; |
| 327 |
|
/** Nonzero when table is being initialized or resized. Updated via CAS. */ |
| 328 |
|
private transient volatile int resizing; |
| 262 |
– |
/** The target load factor for the table. */ |
| 263 |
– |
private transient float loadFactor; |
| 329 |
|
/** The next element count value upon which to resize the table. */ |
| 330 |
|
private transient int threshold; |
| 331 |
< |
/** The initial capacity of the table. */ |
| 332 |
< |
private transient int initCap; |
| 331 |
> |
/** The target capacity; volatile to cover initialization races. */ |
| 332 |
> |
private transient volatile int targetCapacity; |
| 333 |
|
|
| 334 |
|
// views |
| 335 |
< |
transient Set<K> keySet; |
| 336 |
< |
transient Set<Map.Entry<K,V>> entrySet; |
| 337 |
< |
transient Collection<V> values; |
| 335 |
> |
private transient KeySet<K,V> keySet; |
| 336 |
> |
private transient Values<K,V> values; |
| 337 |
> |
private transient EntrySet<K,V> entrySet; |
| 338 |
|
|
| 339 |
|
/** For serialization compatibility. Null unless serialized; see below */ |
| 340 |
< |
Segment<K,V>[] segments; |
| 340 |
> |
private Segment<K,V>[] segments; |
| 341 |
|
|
| 342 |
< |
/** |
| 278 |
< |
* Applies a supplemental hash function to a given hashCode, which |
| 279 |
< |
* defends against poor quality hash functions. The result must |
| 280 |
< |
* be non-negative, and for reasonable performance must have good |
| 281 |
< |
* avalanche properties; i.e., that each bit of the argument |
| 282 |
< |
* affects each bit (except sign bit) of the result. |
| 283 |
< |
*/ |
| 284 |
< |
private static final int spread(int h) { |
| 285 |
< |
// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/ |
| 286 |
< |
h ^= h >>> 16; |
| 287 |
< |
h *= 0x85ebca6b; |
| 288 |
< |
h ^= h >>> 13; |
| 289 |
< |
h *= 0xc2b2ae35; |
| 290 |
< |
return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit |
| 291 |
< |
} |
| 292 |
< |
|
| 293 |
< |
/** |
| 294 |
< |
* Key-value entry. Note that this is never exported out as a |
| 295 |
< |
* user-visible Map.Entry. |
| 296 |
< |
*/ |
| 297 |
< |
static final class Node { |
| 298 |
< |
final int hash; |
| 299 |
< |
final Object key; |
| 300 |
< |
volatile Object val; |
| 301 |
< |
volatile Node next; |
| 302 |
< |
|
| 303 |
< |
Node(int hash, Object key, Object val, Node next) { |
| 304 |
< |
this.hash = hash; |
| 305 |
< |
this.key = key; |
| 306 |
< |
this.val = val; |
| 307 |
< |
this.next = next; |
| 308 |
< |
} |
| 309 |
< |
} |
| 342 |
> |
/* ---------------- Table element access -------------- */ |
| 343 |
|
|
| 344 |
|
/* |
| 345 |
|
* Volatile access methods are used for table elements as well as |
| 346 |
< |
* elements of in-progress next table while resizing. Uses in |
| 347 |
< |
* access and update methods are null checked by callers, and |
| 348 |
< |
* implicitly bounds-checked, relying on the invariants that tab |
| 349 |
< |
* arrays have non-zero size, and all indices are masked with |
| 350 |
< |
* (tab.length - 1) which is never negative and always less than |
| 351 |
< |
* length. The "relaxed" non-volatile forms are used only during |
| 352 |
< |
* table initialization. The only other usage is in |
| 353 |
< |
* HashIterator.advance, which performs explicit checks. |
| 346 |
> |
* elements of in-progress next table while resizing. Uses are |
| 347 |
> |
* null checked by callers, and implicitly bounds-checked, relying |
| 348 |
> |
* on the invariants that tab arrays have non-zero size, and all |
| 349 |
> |
* indices are masked with (tab.length - 1) which is never |
| 350 |
> |
* negative and always less than length. Note that, to be correct |
| 351 |
> |
* wrt arbitrary concurrency errors by users, bounds checks must |
| 352 |
> |
* operate on local variables, which accounts for some odd-looking |
| 353 |
> |
* inline assignments below. |
| 354 |
|
*/ |
| 355 |
|
|
| 356 |
< |
static final Node tabAt(Node[] tab, int i) { // used in HashIterator |
| 356 |
> |
static final Node tabAt(Node[] tab, int i) { // used by InternalIterator |
| 357 |
|
return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE); |
| 358 |
|
} |
| 359 |
|
|
| 365 |
|
UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v); |
| 366 |
|
} |
| 367 |
|
|
| 368 |
< |
private static final Node relaxedTabAt(Node[] tab, int i) { |
| 369 |
< |
return (Node)UNSAFE.getObject(tab, ((long)i<<ASHIFT)+ABASE); |
| 368 |
> |
/* ----------------Table Initialization and Resizing -------------- */ |
| 369 |
> |
|
| 370 |
> |
/** |
| 371 |
> |
* Returns a power of two table size for the given desired capacity. |
| 372 |
> |
* See Hackers Delight, sec 3.2 |
| 373 |
> |
*/ |
| 374 |
> |
private static final int tableSizeFor(int c) { |
| 375 |
> |
int n = c - 1; |
| 376 |
> |
n |= n >>> 1; |
| 377 |
> |
n |= n >>> 2; |
| 378 |
> |
n |= n >>> 4; |
| 379 |
> |
n |= n >>> 8; |
| 380 |
> |
n |= n >>> 16; |
| 381 |
> |
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; |
| 382 |
|
} |
| 383 |
|
|
| 384 |
< |
private static final void relaxedSetTabAt(Node[] tab, int i, Node v) { |
| 385 |
< |
UNSAFE.putObject(tab, ((long)i<<ASHIFT)+ABASE, v); |
| 384 |
> |
/** |
| 385 |
> |
* If not already resizing, initializes or creates next table and |
| 386 |
> |
* transfers bins. Initial table size uses the capacity recorded |
| 387 |
> |
* in targetCapacity. Rechecks occupancy after a transfer to see |
| 388 |
> |
* if another resize is already needed because resizings are |
| 389 |
> |
* lagging additions. |
| 390 |
> |
* |
| 391 |
> |
* @return current table |
| 392 |
> |
*/ |
| 393 |
> |
private final Node[] growTable() { |
| 394 |
> |
if (resizing == 0 && |
| 395 |
> |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
| 396 |
> |
try { |
| 397 |
> |
for (;;) { |
| 398 |
> |
Node[] tab = table; |
| 399 |
> |
int n, c, m; |
| 400 |
> |
if (tab == null) |
| 401 |
> |
n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY; |
| 402 |
> |
else if ((m = tab.length) < MAXIMUM_CAPACITY && |
| 403 |
> |
counter.sum() >= (long)threshold) |
| 404 |
> |
n = m << 1; |
| 405 |
> |
else |
| 406 |
> |
break; |
| 407 |
> |
threshold = n - (n >>> 2) - THRESHOLD_OFFSET; |
| 408 |
> |
Node[] nextTab = new Node[n]; |
| 409 |
> |
if (tab != null) |
| 410 |
> |
transfer(tab, nextTab, |
| 411 |
> |
new Node(SIGN_BIT, nextTab, null, null)); |
| 412 |
> |
table = nextTab; |
| 413 |
> |
if (tab == null) |
| 414 |
> |
break; |
| 415 |
> |
} |
| 416 |
> |
} finally { |
| 417 |
> |
resizing = 0; |
| 418 |
> |
} |
| 419 |
> |
} |
| 420 |
> |
else if (table == null) |
| 421 |
> |
Thread.yield(); // lost initialization race; just spin |
| 422 |
> |
return table; |
| 423 |
> |
} |
| 424 |
> |
|
| 425 |
> |
/** |
| 426 |
> |
* Reclassifies nodes in each bin to new table. Because we are |
| 427 |
> |
* using power-of-two expansion, the elements from each bin must |
| 428 |
> |
* either stay at same index, or move with a power of two |
| 429 |
> |
* offset. We eliminate unnecessary node creation by catching |
| 430 |
> |
* cases where old nodes can be reused because their next fields |
| 431 |
> |
* won't change. Statistically, only about one-sixth of them need |
| 432 |
> |
* cloning when a table doubles. The nodes they replace will be |
| 433 |
> |
* garbage collectable as soon as they are no longer referenced by |
| 434 |
> |
* any reader thread that may be in the midst of concurrently |
| 435 |
> |
* traversing table. |
| 436 |
> |
* |
| 437 |
> |
* Transfers are done from the bottom up to preserve iterator |
| 438 |
> |
* traversability. On each step, the old bin is locked, |
| 439 |
> |
* moved/copied, and then replaced with a forwarding node. |
| 440 |
> |
*/ |
| 441 |
> |
private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) { |
| 442 |
> |
int n = tab.length; |
| 443 |
> |
Node ignore = nextTab[n + n - 1]; // force bounds check |
| 444 |
> |
for (int i = n - 1; i >= 0; --i) { |
| 445 |
> |
for (Node e;;) { |
| 446 |
> |
if ((e = tabAt(tab, i)) != null) { |
| 447 |
> |
boolean validated = false; |
| 448 |
> |
synchronized (e) { |
| 449 |
> |
if (tabAt(tab, i) == e) { |
| 450 |
> |
validated = true; |
| 451 |
> |
Node lo = null, hi = null, lastRun = e; |
| 452 |
> |
int runBit = e.hash & n; |
| 453 |
> |
for (Node p = e.next; p != null; p = p.next) { |
| 454 |
> |
int b = p.hash & n; |
| 455 |
> |
if (b != runBit) { |
| 456 |
> |
runBit = b; |
| 457 |
> |
lastRun = p; |
| 458 |
> |
} |
| 459 |
> |
} |
| 460 |
> |
if (runBit == 0) |
| 461 |
> |
lo = lastRun; |
| 462 |
> |
else |
| 463 |
> |
hi = lastRun; |
| 464 |
> |
for (Node p = e; p != lastRun; p = p.next) { |
| 465 |
> |
int ph = p.hash; |
| 466 |
> |
Object pk = p.key, pv = p.val; |
| 467 |
> |
if ((ph & n) == 0) |
| 468 |
> |
lo = new Node(ph, pk, pv, lo); |
| 469 |
> |
else |
| 470 |
> |
hi = new Node(ph, pk, pv, hi); |
| 471 |
> |
} |
| 472 |
> |
setTabAt(nextTab, i, lo); |
| 473 |
> |
setTabAt(nextTab, i + n, hi); |
| 474 |
> |
setTabAt(tab, i, fwd); |
| 475 |
> |
} |
| 476 |
> |
} |
| 477 |
> |
if (validated) |
| 478 |
> |
break; |
| 479 |
> |
} |
| 480 |
> |
else if (casTabAt(tab, i, e, fwd)) |
| 481 |
> |
break; |
| 482 |
> |
} |
| 483 |
> |
} |
| 484 |
|
} |
| 485 |
|
|
| 486 |
< |
/* ---------------- Access and update operations -------------- */ |
| 486 |
> |
/* ---------------- Internal access and update methods -------------- */ |
| 487 |
|
|
| 488 |
< |
/** Implementation for get and containsKey **/ |
| 488 |
> |
/** |
| 489 |
> |
* Applies a supplemental hash function to a given hashCode, which |
| 490 |
> |
* defends against poor quality hash functions. The result must |
| 491 |
> |
* be non-negative, and for reasonable performance must have good |
| 492 |
> |
* avalanche properties; i.e., that each bit of the argument |
| 493 |
> |
* affects each bit (except sign bit) of the result. |
| 494 |
> |
*/ |
| 495 |
> |
private static final int spread(int h) { |
| 496 |
> |
// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/ |
| 497 |
> |
h ^= h >>> 16; |
| 498 |
> |
h *= 0x85ebca6b; |
| 499 |
> |
h ^= h >>> 13; |
| 500 |
> |
h *= 0xc2b2ae35; |
| 501 |
> |
return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit |
| 502 |
> |
} |
| 503 |
> |
|
| 504 |
> |
/** Implementation for get and containsKey */ |
| 505 |
|
private final Object internalGet(Object k) { |
| 506 |
|
int h = spread(k.hashCode()); |
| 507 |
< |
Node[] tab = table; |
| 508 |
< |
retry: while (tab != null) { |
| 509 |
< |
Node e = tabAt(tab, (tab.length - 1) & h); |
| 510 |
< |
while (e != null) { |
| 511 |
< |
int eh = e.hash; |
| 512 |
< |
if (eh == h) { |
| 354 |
< |
Object ek = e.key, ev = e.val; |
| 355 |
< |
if (ev != null && ek != null && (k == ek || k.equals(ek))) |
| 507 |
> |
retry: for (Node[] tab = table; tab != null;) { |
| 508 |
> |
Node e; Object ek, ev; int eh; // locals to read fields once |
| 509 |
> |
for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) { |
| 510 |
> |
if ((eh = e.hash) == h) { |
| 511 |
> |
if ((ev = e.val) != null && |
| 512 |
> |
((ek = e.key) == k || k.equals(ek))) |
| 513 |
|
return ev; |
| 514 |
|
} |
| 515 |
< |
else if (eh < 0) { // bin was moved during resize |
| 516 |
< |
tab = (Node[])e.key; |
| 515 |
> |
else if (eh < 0) { // sign bit set |
| 516 |
> |
tab = (Node[])e.key; // bin was moved during resize |
| 517 |
|
continue retry; |
| 518 |
|
} |
| 362 |
– |
e = e.next; |
| 519 |
|
} |
| 520 |
|
break; |
| 521 |
|
} |
| 522 |
|
return null; |
| 523 |
|
} |
| 524 |
|
|
| 525 |
< |
/** Implementation for put and putIfAbsent **/ |
| 525 |
> |
/** Implementation for put and putIfAbsent */ |
| 526 |
|
private final Object internalPut(Object k, Object v, boolean replace) { |
| 527 |
|
int h = spread(k.hashCode()); |
| 528 |
< |
Object oldVal = null; // the previous value or null if none |
| 529 |
< |
Node[] tab = table; |
| 530 |
< |
for (;;) { |
| 375 |
< |
Node e; int i; |
| 528 |
> |
Object oldVal = null; // previous value or null if none |
| 529 |
> |
for (Node[] tab = table;;) { |
| 530 |
> |
Node e; int i; Object ek, ev; |
| 531 |
|
if (tab == null) |
| 532 |
< |
tab = grow(0); |
| 532 |
> |
tab = growTable(); |
| 533 |
|
else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
| 534 |
|
if (casTabAt(tab, i, null, new Node(h, k, v, null))) |
| 535 |
< |
break; |
| 535 |
> |
break; // no lock when adding to empty bin |
| 536 |
|
} |
| 537 |
< |
else if (e.hash < 0) |
| 537 |
> |
else if (e.hash < 0) // resized -- restart with new table |
| 538 |
|
tab = (Node[])e.key; |
| 539 |
+ |
else if (!replace && e.hash == h && (ev = e.val) != null && |
| 540 |
+ |
((ek = e.key) == k || k.equals(ek))) { |
| 541 |
+ |
if (tabAt(tab, i) == e) { // inspect and validate 1st node |
| 542 |
+ |
oldVal = ev; // without lock for putIfAbsent |
| 543 |
+ |
break; |
| 544 |
+ |
} |
| 545 |
+ |
} |
| 546 |
|
else { |
| 547 |
|
boolean validated = false; |
| 548 |
|
boolean checkSize = false; |
| 549 |
< |
synchronized (e) { |
| 550 |
< |
Node first = e; |
| 551 |
< |
for (;;) { |
| 552 |
< |
Object ek, ev; |
| 553 |
< |
if ((ev = e.val) == null) |
| 554 |
< |
break; |
| 555 |
< |
if (e.hash == h && (ek = e.key) != null && |
| 394 |
< |
(k == ek || k.equals(ek))) { |
| 395 |
< |
if (tabAt(tab, i) == first) { |
| 396 |
< |
validated = true; |
| 549 |
> |
synchronized (e) { // lock the 1st node of bin list |
| 550 |
> |
if (tabAt(tab, i) == e) { |
| 551 |
> |
validated = true; // retry if 1st already deleted |
| 552 |
> |
for (Node first = e;;) { |
| 553 |
> |
if (e.hash == h && |
| 554 |
> |
((ek = e.key) == k || k.equals(ek)) && |
| 555 |
> |
(ev = e.val) != null) { |
| 556 |
|
oldVal = ev; |
| 557 |
|
if (replace) |
| 558 |
|
e.val = v; |
| 559 |
+ |
break; |
| 560 |
|
} |
| 561 |
< |
break; |
| 562 |
< |
} |
| 403 |
< |
Node last = e; |
| 404 |
< |
if ((e = e.next) == null) { |
| 405 |
< |
if (tabAt(tab, i) == first) { |
| 406 |
< |
validated = true; |
| 561 |
> |
Node last = e; |
| 562 |
> |
if ((e = e.next) == null) { |
| 563 |
|
last.next = new Node(h, k, v, null); |
| 564 |
|
if (last != first || tab.length <= 64) |
| 565 |
|
checkSize = true; |
| 566 |
+ |
break; |
| 567 |
|
} |
| 411 |
– |
break; |
| 568 |
|
} |
| 569 |
|
} |
| 570 |
|
} |
| 571 |
|
if (validated) { |
| 572 |
|
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
| 573 |
< |
resizing == 0 && counter.sum() >= threshold) |
| 574 |
< |
grow(0); |
| 573 |
> |
resizing == 0 && counter.sum() >= (long)threshold) |
| 574 |
> |
growTable(); |
| 575 |
|
break; |
| 576 |
|
} |
| 577 |
|
} |
| 578 |
|
} |
| 579 |
|
if (oldVal == null) |
| 580 |
< |
counter.increment(); |
| 580 |
> |
counter.increment(); // update counter outside of locks |
| 581 |
|
return oldVal; |
| 582 |
|
} |
| 583 |
|
|
| 584 |
|
/** |
| 585 |
< |
* Covers the four public remove/replace methods: Replaces node |
| 586 |
< |
* value with v, conditional upon match of cv if non-null. If |
| 587 |
< |
* resulting value is null, delete. |
| 585 |
> |
* Implementation for the four public remove/replace methods: |
| 586 |
> |
* Replaces node value with v, conditional upon match of cv if |
| 587 |
> |
* non-null. If resulting value is null, delete. |
| 588 |
|
*/ |
| 589 |
|
private final Object internalReplace(Object k, Object v, Object cv) { |
| 590 |
|
int h = spread(k.hashCode()); |
| 591 |
< |
Object oldVal = null; |
| 592 |
< |
Node e; int i; |
| 593 |
< |
Node[] tab = table; |
| 594 |
< |
while (tab != null && |
| 595 |
< |
(e = tabAt(tab, i = (tab.length - 1) & h)) != null) { |
| 596 |
< |
if (e.hash < 0) |
| 591 |
> |
for (Node[] tab = table;;) { |
| 592 |
> |
Node e; int i; |
| 593 |
> |
if (tab == null || |
| 594 |
> |
(e = tabAt(tab, i = (tab.length - 1) & h)) == null) |
| 595 |
> |
return null; |
| 596 |
> |
else if (e.hash < 0) |
| 597 |
|
tab = (Node[])e.key; |
| 598 |
|
else { |
| 599 |
+ |
Object oldVal = null; |
| 600 |
|
boolean validated = false; |
| 601 |
|
boolean deleted = false; |
| 602 |
|
synchronized (e) { |
| 603 |
< |
Node pred = null; |
| 604 |
< |
Node first = e; |
| 605 |
< |
for (;;) { |
| 606 |
< |
Object ek, ev; |
| 607 |
< |
if ((ev = e.val) == null) |
| 608 |
< |
break; |
| 609 |
< |
if (e.hash == h && (ek = e.key) != null && |
| 610 |
< |
(k == ek || k.equals(ek))) { |
| 454 |
< |
if (tabAt(tab, i) == first) { |
| 455 |
< |
validated = true; |
| 603 |
> |
if (tabAt(tab, i) == e) { |
| 604 |
> |
validated = true; |
| 605 |
> |
Node pred = null; |
| 606 |
> |
do { |
| 607 |
> |
Object ek, ev; |
| 608 |
> |
if (e.hash == h && |
| 609 |
> |
((ek = e.key) == k || k.equals(ek)) && |
| 610 |
> |
((ev = e.val) != null)) { |
| 611 |
|
if (cv == null || cv == ev || cv.equals(ev)) { |
| 612 |
|
oldVal = ev; |
| 613 |
|
if ((e.val = v) == null) { |
| 619 |
|
setTabAt(tab, i, en); |
| 620 |
|
} |
| 621 |
|
} |
| 622 |
+ |
break; |
| 623 |
|
} |
| 624 |
< |
break; |
| 469 |
< |
} |
| 470 |
< |
pred = e; |
| 471 |
< |
if ((e = e.next) == null) { |
| 472 |
< |
if (tabAt(tab, i) == first) |
| 473 |
< |
validated = true; |
| 474 |
< |
break; |
| 475 |
< |
} |
| 624 |
> |
} while ((e = (pred = e).next) != null); |
| 625 |
|
} |
| 626 |
|
} |
| 627 |
|
if (validated) { |
| 628 |
|
if (deleted) |
| 629 |
|
counter.decrement(); |
| 630 |
< |
break; |
| 630 |
> |
return oldVal; |
| 631 |
|
} |
| 632 |
|
} |
| 633 |
|
} |
| 485 |
– |
return oldVal; |
| 634 |
|
} |
| 635 |
|
|
| 636 |
< |
/** Implementation for computeIfAbsent and compute */ |
| 636 |
> |
/** Implementation for computeIfAbsent and compute. Like put, but messier. */ |
| 637 |
|
@SuppressWarnings("unchecked") |
| 638 |
|
private final V internalCompute(K k, |
| 639 |
|
MappingFunction<? super K, ? extends V> f, |
| 641 |
|
int h = spread(k.hashCode()); |
| 642 |
|
V val = null; |
| 643 |
|
boolean added = false; |
| 496 |
– |
boolean validated = false; |
| 644 |
|
Node[] tab = table; |
| 645 |
< |
do { |
| 646 |
< |
Node e; int i; |
| 645 |
> |
outer:for (;;) { |
| 646 |
> |
Node e; int i; Object ek, ev; |
| 647 |
|
if (tab == null) |
| 648 |
< |
tab = grow(0); |
| 648 |
> |
tab = growTable(); |
| 649 |
|
else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
| 650 |
|
Node node = new Node(h, k, null, null); |
| 651 |
< |
synchronized (node) { |
| 651 |
> |
boolean validated = false; |
| 652 |
> |
synchronized (node) { // must lock while computing value |
| 653 |
|
if (casTabAt(tab, i, null, node)) { |
| 654 |
|
validated = true; |
| 655 |
|
try { |
| 664 |
|
} |
| 665 |
|
} |
| 666 |
|
} |
| 667 |
+ |
if (validated) |
| 668 |
+ |
break; |
| 669 |
|
} |
| 670 |
|
else if (e.hash < 0) |
| 671 |
|
tab = (Node[])e.key; |
| 672 |
+ |
else if (!replace && e.hash == h && (ev = e.val) != null && |
| 673 |
+ |
((ek = e.key) == k || k.equals(ek))) { |
| 674 |
+ |
if (tabAt(tab, i) == e) { |
| 675 |
+ |
val = (V)ev; |
| 676 |
+ |
break; |
| 677 |
+ |
} |
| 678 |
+ |
} |
| 679 |
|
else if (Thread.holdsLock(e)) |
| 680 |
|
throw new IllegalStateException("Recursive map computation"); |
| 681 |
|
else { |
| 682 |
+ |
boolean validated = false; |
| 683 |
|
boolean checkSize = false; |
| 684 |
|
synchronized (e) { |
| 685 |
< |
Node first = e; |
| 686 |
< |
for (;;) { |
| 687 |
< |
Object ek, ev; |
| 688 |
< |
if ((ev = e.val) == null) |
| 689 |
< |
break; |
| 690 |
< |
if (e.hash == h && (ek = e.key) != null && |
| 691 |
< |
(k == ek || k.equals(ek))) { |
| 692 |
< |
if (tabAt(tab, i) == first) { |
| 693 |
< |
validated = true; |
| 536 |
< |
if (replace && (ev = f.map(k)) != null) |
| 537 |
< |
e.val = ev; |
| 685 |
> |
if (tabAt(tab, i) == e) { |
| 686 |
> |
validated = true; |
| 687 |
> |
for (Node first = e;;) { |
| 688 |
> |
if (e.hash == h && |
| 689 |
> |
((ek = e.key) == k || k.equals(ek)) && |
| 690 |
> |
((ev = e.val) != null)) { |
| 691 |
> |
Object fv; |
| 692 |
> |
if (replace && (fv = f.map(k)) != null) |
| 693 |
> |
ev = e.val = fv; |
| 694 |
|
val = (V)ev; |
| 695 |
+ |
break; |
| 696 |
|
} |
| 697 |
< |
break; |
| 698 |
< |
} |
| 542 |
< |
Node last = e; |
| 543 |
< |
if ((e = e.next) == null) { |
| 544 |
< |
if (tabAt(tab, i) == first) { |
| 545 |
< |
validated = true; |
| 697 |
> |
Node last = e; |
| 698 |
> |
if ((e = e.next) == null) { |
| 699 |
|
if ((val = f.map(k)) != null) { |
| 700 |
|
last.next = new Node(h, k, val, null); |
| 701 |
|
added = true; |
| 702 |
|
if (last != first || tab.length <= 64) |
| 703 |
|
checkSize = true; |
| 704 |
|
} |
| 705 |
+ |
break; |
| 706 |
|
} |
| 553 |
– |
break; |
| 707 |
|
} |
| 708 |
|
} |
| 709 |
|
} |
| 710 |
< |
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
| 711 |
< |
resizing == 0 && counter.sum() >= threshold) |
| 712 |
< |
grow(0); |
| 710 |
> |
if (validated) { |
| 711 |
> |
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
| 712 |
> |
resizing == 0 && counter.sum() >= (long)threshold) |
| 713 |
> |
growTable(); |
| 714 |
> |
break; |
| 715 |
> |
} |
| 716 |
|
} |
| 717 |
< |
} while (!validated); |
| 717 |
> |
} |
| 718 |
|
if (added) |
| 719 |
|
counter.increment(); |
| 720 |
|
return val; |
| 721 |
|
} |
| 722 |
|
|
| 567 |
– |
/* |
| 568 |
– |
* Reclassifies nodes in each bin to new table. Because we are |
| 569 |
– |
* using power-of-two expansion, the elements from each bin must |
| 570 |
– |
* either stay at same index, or move with a power of two |
| 571 |
– |
* offset. We eliminate unnecessary node creation by catching |
| 572 |
– |
* cases where old nodes can be reused because their next fields |
| 573 |
– |
* won't change. Statistically, at the default threshold, only |
| 574 |
– |
* about one-sixth of them need cloning when a table doubles. The |
| 575 |
– |
* nodes they replace will be garbage collectable as soon as they |
| 576 |
– |
* are no longer referenced by any reader thread that may be in |
| 577 |
– |
* the midst of concurrently traversing table. |
| 578 |
– |
* |
| 579 |
– |
* Transfers are done from the bottom up to preserve iterator |
| 580 |
– |
* traversability. On each step, the old bin is locked, |
| 581 |
– |
* moved/copied, and then replaced with a forwarding node. |
| 582 |
– |
*/ |
| 583 |
– |
private static final void transfer(Node[] tab, Node[] nextTab) { |
| 584 |
– |
int n = tab.length; |
| 585 |
– |
int mask = nextTab.length - 1; |
| 586 |
– |
Node fwd = new Node(MOVED, nextTab, null, null); |
| 587 |
– |
for (int i = n - 1; i >= 0; --i) { |
| 588 |
– |
for (Node e;;) { |
| 589 |
– |
if ((e = tabAt(tab, i)) == null) { |
| 590 |
– |
if (casTabAt(tab, i, e, fwd)) |
| 591 |
– |
break; |
| 592 |
– |
} |
| 593 |
– |
else { |
| 594 |
– |
boolean validated = false; |
| 595 |
– |
synchronized (e) { |
| 596 |
– |
int idx = e.hash & mask; |
| 597 |
– |
Node lastRun = e; |
| 598 |
– |
for (Node p = e.next; p != null; p = p.next) { |
| 599 |
– |
int j = p.hash & mask; |
| 600 |
– |
if (j != idx) { |
| 601 |
– |
idx = j; |
| 602 |
– |
lastRun = p; |
| 603 |
– |
} |
| 604 |
– |
} |
| 605 |
– |
if (tabAt(tab, i) == e) { |
| 606 |
– |
validated = true; |
| 607 |
– |
relaxedSetTabAt(nextTab, idx, lastRun); |
| 608 |
– |
for (Node p = e; p != lastRun; p = p.next) { |
| 609 |
– |
int h = p.hash; |
| 610 |
– |
int j = h & mask; |
| 611 |
– |
Node r = relaxedTabAt(nextTab, j); |
| 612 |
– |
relaxedSetTabAt(nextTab, j, |
| 613 |
– |
new Node(h, p.key, p.val, r)); |
| 614 |
– |
} |
| 615 |
– |
setTabAt(tab, i, fwd); |
| 616 |
– |
} |
| 617 |
– |
} |
| 618 |
– |
if (validated) |
| 619 |
– |
break; |
| 620 |
– |
} |
| 621 |
– |
} |
| 622 |
– |
} |
| 623 |
– |
} |
| 624 |
– |
|
| 625 |
– |
/** |
| 626 |
– |
* If not already resizing, initializes or creates next table and |
| 627 |
– |
* transfers bins. Rechecks occupancy after a transfer to see if |
| 628 |
– |
* another resize is already needed because resizings are lagging |
| 629 |
– |
* additions. |
| 630 |
– |
* |
| 631 |
– |
* @param sizeHint overridden capacity target (nonzero only from putAll) |
| 632 |
– |
* @return current table |
| 633 |
– |
*/ |
| 634 |
– |
private final Node[] grow(int sizeHint) { |
| 635 |
– |
if (resizing == 0 && |
| 636 |
– |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
| 637 |
– |
try { |
| 638 |
– |
for (;;) { |
| 639 |
– |
int cap, n; |
| 640 |
– |
Node[] tab = table; |
| 641 |
– |
if (tab == null) { |
| 642 |
– |
int c = initCap; |
| 643 |
– |
if (c < sizeHint) |
| 644 |
– |
c = sizeHint; |
| 645 |
– |
if (c == DEFAULT_CAPACITY) |
| 646 |
– |
cap = c; |
| 647 |
– |
else if (c >= MAXIMUM_CAPACITY) |
| 648 |
– |
cap = MAXIMUM_CAPACITY; |
| 649 |
– |
else { |
| 650 |
– |
cap = MINIMUM_CAPACITY; |
| 651 |
– |
while (cap < c) |
| 652 |
– |
cap <<= 1; |
| 653 |
– |
} |
| 654 |
– |
} |
| 655 |
– |
else if ((n = tab.length) < MAXIMUM_CAPACITY && |
| 656 |
– |
(sizeHint <= 0 || n < sizeHint)) |
| 657 |
– |
cap = n << 1; |
| 658 |
– |
else |
| 659 |
– |
break; |
| 660 |
– |
threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET; |
| 661 |
– |
Node[] nextTab = new Node[cap]; |
| 662 |
– |
if (tab != null) |
| 663 |
– |
transfer(tab, nextTab); |
| 664 |
– |
table = nextTab; |
| 665 |
– |
if (tab == null || cap >= MAXIMUM_CAPACITY || |
| 666 |
– |
(sizeHint > 0 && cap >= sizeHint) || |
| 667 |
– |
counter.sum() < threshold) |
| 668 |
– |
break; |
| 669 |
– |
} |
| 670 |
– |
} finally { |
| 671 |
– |
resizing = 0; |
| 672 |
– |
} |
| 673 |
– |
} |
| 674 |
– |
else if (table == null) |
| 675 |
– |
Thread.yield(); // lost initialization race; just spin |
| 676 |
– |
return table; |
| 677 |
– |
} |
| 678 |
– |
|
| 679 |
– |
/** |
| 680 |
– |
* Implementation for putAll and constructor with Map |
| 681 |
– |
* argument. Tries to first override initial capacity or grow |
| 682 |
– |
* based on map size to pre-allocate table space. |
| 683 |
– |
*/ |
| 684 |
– |
private final void internalPutAll(Map<? extends K, ? extends V> m) { |
| 685 |
– |
int s = m.size(); |
| 686 |
– |
grow((s >= (MAXIMUM_CAPACITY >>> 1)) ? s : s + (s >>> 1)); |
| 687 |
– |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { |
| 688 |
– |
Object k = e.getKey(); |
| 689 |
– |
Object v = e.getValue(); |
| 690 |
– |
if (k == null || v == null) |
| 691 |
– |
throw new NullPointerException(); |
| 692 |
– |
internalPut(k, v, true); |
| 693 |
– |
} |
| 694 |
– |
} |
| 695 |
– |
|
| 723 |
|
/** |
| 724 |
|
* Implementation for clear. Steps through each bin, removing all nodes. |
| 725 |
|
*/ |
| 726 |
|
private final void internalClear() { |
| 727 |
< |
long deletions = 0L; |
| 727 |
> |
long delta = 0L; // negative number of deletions |
| 728 |
|
int i = 0; |
| 729 |
|
Node[] tab = table; |
| 730 |
|
while (tab != null && i < tab.length) { |
| 738 |
|
synchronized (e) { |
| 739 |
|
if (tabAt(tab, i) == e) { |
| 740 |
|
validated = true; |
| 741 |
+ |
Node en; |
| 742 |
|
do { |
| 743 |
< |
if (e.val != null) { |
| 743 |
> |
en = e.next; |
| 744 |
> |
if (e.val != null) { // currently always true |
| 745 |
|
e.val = null; |
| 746 |
< |
++deletions; |
| 746 |
> |
--delta; |
| 747 |
|
} |
| 748 |
< |
} while ((e = e.next) != null); |
| 748 |
> |
} while ((e = en) != null); |
| 749 |
|
setTabAt(tab, i, null); |
| 750 |
|
} |
| 751 |
|
} |
| 752 |
< |
if (validated) { |
| 752 |
> |
if (validated) |
| 753 |
|
++i; |
| 725 |
– |
if (deletions > THRESHOLD_OFFSET) { // bound lag in counts |
| 726 |
– |
counter.add(-deletions); |
| 727 |
– |
deletions = 0L; |
| 728 |
– |
} |
| 729 |
– |
} |
| 754 |
|
} |
| 755 |
|
} |
| 756 |
< |
if (deletions != 0L) |
| 733 |
< |
counter.add(-deletions); |
| 756 |
> |
counter.add(delta); |
| 757 |
|
} |
| 758 |
|
|
| 759 |
< |
/** |
| 737 |
< |
* Base class for key, value, and entry iterators, plus internal |
| 738 |
< |
* implementations of public traversal-based methods, to avoid |
| 739 |
< |
* duplicating traversal code. |
| 740 |
< |
*/ |
| 741 |
< |
class HashIterator { |
| 742 |
< |
private Node next; // the next entry to return |
| 743 |
< |
private Node[] tab; // current table; updated if resized |
| 744 |
< |
private Node lastReturned; // the last entry returned, for remove |
| 745 |
< |
private Object nextVal; // cached value of next |
| 746 |
< |
private int index; // index of bin to use next |
| 747 |
< |
private int baseIndex; // current index of initial table |
| 748 |
< |
private final int baseSize; // initial table size |
| 749 |
< |
|
| 750 |
< |
HashIterator() { |
| 751 |
< |
Node[] t = tab = table; |
| 752 |
< |
if (t == null) |
| 753 |
< |
baseSize = 0; |
| 754 |
< |
else { |
| 755 |
< |
baseSize = t.length; |
| 756 |
< |
advance(null); |
| 757 |
< |
} |
| 758 |
< |
} |
| 759 |
< |
|
| 760 |
< |
public final boolean hasNext() { return next != null; } |
| 761 |
< |
public final boolean hasMoreElements() { return next != null; } |
| 759 |
> |
/* ----------------Table Traversal -------------- */ |
| 760 |
|
|
| 761 |
< |
/** |
| 762 |
< |
* Advances next. Normally, iteration proceeds bin-by-bin |
| 763 |
< |
* traversing lists. However, if the table has been resized, |
| 764 |
< |
* then all future steps must traverse both the bin at the |
| 765 |
< |
* current index as well as at (index + baseSize); and so on |
| 766 |
< |
* for further resizings. To paranoically cope with potential |
| 767 |
< |
* (improper) sharing of iterators across threads, table reads |
| 768 |
< |
* are bounds-checked. |
| 769 |
< |
*/ |
| 770 |
< |
final void advance(Node e) { |
| 771 |
< |
for (;;) { |
| 772 |
< |
Node[] t; int i; // for bounds checks |
| 773 |
< |
if (e != null) { |
| 774 |
< |
Object ek = e.key, ev = e.val; |
| 775 |
< |
if (ev != null && ek != null) { |
| 776 |
< |
nextVal = ev; |
| 777 |
< |
next = e; |
| 778 |
< |
break; |
| 779 |
< |
} |
| 761 |
> |
/** |
| 762 |
> |
* Encapsulates traversal for methods such as containsValue; also |
| 763 |
> |
* serves as a base class for other iterators. |
| 764 |
> |
* |
| 765 |
> |
* At each step, the iterator snapshots the key ("nextKey") and |
| 766 |
> |
* value ("nextVal") of a valid node (i.e., one that, at point of |
| 767 |
> |
* snapshot, has a nonnull user value). Because val fields can |
| 768 |
> |
* change (including to null, indicating deletion), field nextVal |
| 769 |
> |
* might not be accurate at point of use, but still maintains the |
| 770 |
> |
* weak consistency property of holding a value that was once |
| 771 |
> |
* valid. |
| 772 |
> |
* |
| 773 |
> |
* Internal traversals directly access these fields, as in: |
| 774 |
> |
* {@code while (it.next != null) { process(nextKey); it.advance(); }} |
| 775 |
> |
* |
| 776 |
> |
* Exported iterators (subclasses of ViewIterator) extract key, |
| 777 |
> |
* value, or key-value pairs as return values of Iterator.next(), |
| 778 |
> |
* and encapsulate the it.next check as hasNext(); |
| 779 |
> |
* |
| 780 |
> |
* The iterator visits each valid node that was reachable upon |
| 781 |
> |
* iterator construction once. It might miss some that were added |
| 782 |
> |
* to a bin after the bin was visited, which is OK wrt consistency |
| 783 |
> |
* guarantees. Maintaining this property in the face of possible |
| 784 |
> |
* ongoing resizes requires a fair amount of bookkeeping state |
| 785 |
> |
* that is difficult to optimize away amidst volatile accesses. |
| 786 |
> |
* Even so, traversal maintains reasonable throughput. |
| 787 |
> |
* |
| 788 |
> |
* Normally, iteration proceeds bin-by-bin traversing lists. |
| 789 |
> |
* However, if the table has been resized, then all future steps |
| 790 |
> |
* must traverse both the bin at the current index as well as at |
| 791 |
> |
* (index + baseSize); and so on for further resizings. To |
| 792 |
> |
* paranoically cope with potential sharing by users of iterators |
| 793 |
> |
* across threads, iteration terminates if a bounds checks fails |
| 794 |
> |
* for a table read. |
| 795 |
> |
* |
| 796 |
> |
* The range-based constructor enables creation of parallel |
| 797 |
> |
* range-splitting traversals. (Not yet implemented.) |
| 798 |
> |
*/ |
| 799 |
> |
static class InternalIterator { |
| 800 |
> |
Node next; // the next entry to use |
| 801 |
> |
Node last; // the last entry used |
| 802 |
> |
Object nextKey; // cached key field of next |
| 803 |
> |
Object nextVal; // cached val field of next |
| 804 |
> |
Node[] tab; // current table; updated if resized |
| 805 |
> |
int index; // index of bin to use next |
| 806 |
> |
int baseIndex; // current index of initial table |
| 807 |
> |
final int baseLimit; // index bound for initial table |
| 808 |
> |
final int baseSize; // initial table size |
| 809 |
> |
|
| 810 |
> |
/** Creates iterator for all entries in the table. */ |
| 811 |
> |
InternalIterator(Node[] tab) { |
| 812 |
> |
this.tab = tab; |
| 813 |
> |
baseLimit = baseSize = (tab == null) ? 0 : tab.length; |
| 814 |
> |
index = baseIndex = 0; |
| 815 |
> |
next = null; |
| 816 |
> |
advance(); |
| 817 |
> |
} |
| 818 |
> |
|
| 819 |
> |
/** Creates iterator for the given range of the table */ |
| 820 |
> |
InternalIterator(Node[] tab, int lo, int hi) { |
| 821 |
> |
this.tab = tab; |
| 822 |
> |
baseSize = (tab == null) ? 0 : tab.length; |
| 823 |
> |
baseLimit = (hi <= baseSize) ? hi : baseSize; |
| 824 |
> |
index = baseIndex = lo; |
| 825 |
> |
next = null; |
| 826 |
> |
advance(); |
| 827 |
> |
} |
| 828 |
> |
|
| 829 |
> |
/** Advances next. See above for explanation. */ |
| 830 |
> |
final void advance() { |
| 831 |
> |
Node e = last = next; |
| 832 |
> |
outer: do { |
| 833 |
> |
if (e != null) // pass used or skipped node |
| 834 |
|
e = e.next; |
| 835 |
+ |
while (e == null) { // get to next non-null bin |
| 836 |
+ |
Node[] t; int b, i, n; // checks must use locals |
| 837 |
+ |
if ((b = baseIndex) >= baseLimit || (i = index) < 0 || |
| 838 |
+ |
(t = tab) == null || i >= (n = t.length)) |
| 839 |
+ |
break outer; |
| 840 |
+ |
else if ((e = tabAt(t, i)) != null && e.hash < 0) |
| 841 |
+ |
tab = (Node[])e.key; // restarts due to null val |
| 842 |
+ |
else // visit upper slots if present |
| 843 |
+ |
index = (i += baseSize) < n ? i : (baseIndex = b + 1); |
| 844 |
|
} |
| 845 |
< |
else if (baseIndex < baseSize && (t = tab) != null && |
| 846 |
< |
t.length > (i = index) && i >= 0) { |
| 847 |
< |
if ((e = tabAt(t, i)) != null && e.hash < 0) { |
| 787 |
< |
tab = (Node[])e.key; |
| 788 |
< |
e = null; |
| 789 |
< |
} |
| 790 |
< |
else if (i + baseSize < t.length) |
| 791 |
< |
index += baseSize; // visit forwarded upper slots |
| 792 |
< |
else |
| 793 |
< |
index = ++baseIndex; |
| 794 |
< |
} |
| 795 |
< |
else { |
| 796 |
< |
next = null; |
| 797 |
< |
break; |
| 798 |
< |
} |
| 799 |
< |
} |
| 800 |
< |
} |
| 801 |
< |
|
| 802 |
< |
final Object nextKey() { |
| 803 |
< |
Node e = next; |
| 804 |
< |
if (e == null) |
| 805 |
< |
throw new NoSuchElementException(); |
| 806 |
< |
Object k = e.key; |
| 807 |
< |
advance((lastReturned = e).next); |
| 808 |
< |
return k; |
| 809 |
< |
} |
| 810 |
< |
|
| 811 |
< |
final Object nextValue() { |
| 812 |
< |
Node e = next; |
| 813 |
< |
if (e == null) |
| 814 |
< |
throw new NoSuchElementException(); |
| 815 |
< |
Object v = nextVal; |
| 816 |
< |
advance((lastReturned = e).next); |
| 817 |
< |
return v; |
| 818 |
< |
} |
| 819 |
< |
|
| 820 |
< |
final WriteThroughEntry nextEntry() { |
| 821 |
< |
Node e = next; |
| 822 |
< |
if (e == null) |
| 823 |
< |
throw new NoSuchElementException(); |
| 824 |
< |
WriteThroughEntry entry = |
| 825 |
< |
new WriteThroughEntry(e.key, nextVal); |
| 826 |
< |
advance((lastReturned = e).next); |
| 827 |
< |
return entry; |
| 828 |
< |
} |
| 829 |
< |
|
| 830 |
< |
public final void remove() { |
| 831 |
< |
if (lastReturned == null) |
| 832 |
< |
throw new IllegalStateException(); |
| 833 |
< |
ConcurrentHashMapV8.this.remove(lastReturned.key); |
| 834 |
< |
lastReturned = null; |
| 835 |
< |
} |
| 836 |
< |
|
| 837 |
< |
/** Helper for serialization */ |
| 838 |
< |
final void writeEntries(java.io.ObjectOutputStream s) |
| 839 |
< |
throws java.io.IOException { |
| 840 |
< |
Node e; |
| 841 |
< |
while ((e = next) != null) { |
| 842 |
< |
s.writeObject(e.key); |
| 843 |
< |
s.writeObject(nextVal); |
| 844 |
< |
advance(e.next); |
| 845 |
< |
} |
| 846 |
< |
} |
| 847 |
< |
|
| 848 |
< |
/** Helper for containsValue */ |
| 849 |
< |
final boolean containsVal(Object value) { |
| 850 |
< |
if (value != null) { |
| 851 |
< |
Node e; |
| 852 |
< |
while ((e = next) != null) { |
| 853 |
< |
Object v = nextVal; |
| 854 |
< |
if (value == v || value.equals(v)) |
| 855 |
< |
return true; |
| 856 |
< |
advance(e.next); |
| 857 |
< |
} |
| 858 |
< |
} |
| 859 |
< |
return false; |
| 860 |
< |
} |
| 861 |
< |
|
| 862 |
< |
/** Helper for Map.hashCode */ |
| 863 |
< |
final int mapHashCode() { |
| 864 |
< |
int h = 0; |
| 865 |
< |
Node e; |
| 866 |
< |
while ((e = next) != null) { |
| 867 |
< |
h += e.key.hashCode() ^ nextVal.hashCode(); |
| 868 |
< |
advance(e.next); |
| 869 |
< |
} |
| 870 |
< |
return h; |
| 871 |
< |
} |
| 872 |
< |
|
| 873 |
< |
/** Helper for Map.toString */ |
| 874 |
< |
final String mapToString() { |
| 875 |
< |
Node e = next; |
| 876 |
< |
if (e == null) |
| 877 |
< |
return "{}"; |
| 878 |
< |
StringBuilder sb = new StringBuilder(); |
| 879 |
< |
sb.append('{'); |
| 880 |
< |
for (;;) { |
| 881 |
< |
sb.append(e.key == this ? "(this Map)" : e.key); |
| 882 |
< |
sb.append('='); |
| 883 |
< |
sb.append(nextVal == this ? "(this Map)" : nextVal); |
| 884 |
< |
advance(e.next); |
| 885 |
< |
if ((e = next) != null) |
| 886 |
< |
sb.append(',').append(' '); |
| 887 |
< |
else |
| 888 |
< |
return sb.append('}').toString(); |
| 889 |
< |
} |
| 845 |
> |
nextKey = e.key; |
| 846 |
> |
} while ((nextVal = e.val) == null); // skip deleted or special nodes |
| 847 |
> |
next = e; |
| 848 |
|
} |
| 849 |
|
} |
| 850 |
|
|
| 851 |
|
/* ---------------- Public operations -------------- */ |
| 852 |
|
|
| 853 |
|
/** |
| 854 |
< |
* Creates a new, empty map with the specified initial |
| 897 |
< |
* capacity, load factor and concurrency level. |
| 898 |
< |
* |
| 899 |
< |
* @param initialCapacity the initial capacity. The implementation |
| 900 |
< |
* performs internal sizing to accommodate this many elements. |
| 901 |
< |
* @param loadFactor the load factor threshold, used to control resizing. |
| 902 |
< |
* Resizing may be performed when the average number of elements per |
| 903 |
< |
* bin exceeds this threshold. |
| 904 |
< |
* @param concurrencyLevel the estimated number of concurrently |
| 905 |
< |
* updating threads. The implementation may use this value as |
| 906 |
< |
* a sizing hint. |
| 907 |
< |
* @throws IllegalArgumentException if the initial capacity is |
| 908 |
< |
* negative or the load factor or concurrencyLevel are |
| 909 |
< |
* nonpositive. |
| 854 |
> |
* Creates a new, empty map with the default initial table size (16), |
| 855 |
|
*/ |
| 856 |
< |
public ConcurrentHashMapV8(int initialCapacity, |
| 912 |
< |
float loadFactor, int concurrencyLevel) { |
| 913 |
< |
if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0) |
| 914 |
< |
throw new IllegalArgumentException(); |
| 915 |
< |
this.initCap = initialCapacity; |
| 916 |
< |
this.loadFactor = loadFactor; |
| 856 |
> |
public ConcurrentHashMapV8() { |
| 857 |
|
this.counter = new LongAdder(); |
| 858 |
+ |
this.targetCapacity = DEFAULT_CAPACITY; |
| 859 |
|
} |
| 860 |
|
|
| 861 |
|
/** |
| 862 |
< |
* Creates a new, empty map with the specified initial capacity |
| 863 |
< |
* and load factor and with the default concurrencyLevel (16). |
| 862 |
> |
* Creates a new, empty map with an initial table size |
| 863 |
> |
* accommodating the specified number of elements without the need |
| 864 |
> |
* to dynamically resize. |
| 865 |
|
* |
| 866 |
|
* @param initialCapacity The implementation performs internal |
| 867 |
|
* sizing to accommodate this many elements. |
| 926 |
– |
* @param loadFactor the load factor threshold, used to control resizing. |
| 927 |
– |
* Resizing may be performed when the average number of elements per |
| 928 |
– |
* bin exceeds this threshold. |
| 868 |
|
* @throws IllegalArgumentException if the initial capacity of |
| 869 |
< |
* elements is negative or the load factor is nonpositive |
| 931 |
< |
* |
| 932 |
< |
* @since 1.6 |
| 869 |
> |
* elements is negative |
| 870 |
|
*/ |
| 871 |
< |
public ConcurrentHashMapV8(int initialCapacity, float loadFactor) { |
| 872 |
< |
this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL); |
| 871 |
> |
public ConcurrentHashMapV8(int initialCapacity) { |
| 872 |
> |
if (initialCapacity < 0) |
| 873 |
> |
throw new IllegalArgumentException(); |
| 874 |
> |
int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? |
| 875 |
> |
MAXIMUM_CAPACITY : |
| 876 |
> |
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); |
| 877 |
> |
this.counter = new LongAdder(); |
| 878 |
> |
this.targetCapacity = cap; |
| 879 |
|
} |
| 880 |
|
|
| 881 |
|
/** |
| 882 |
< |
* Creates a new, empty map with the specified initial capacity, |
| 940 |
< |
* and with default load factor (0.75) and concurrencyLevel (16). |
| 882 |
> |
* Creates a new map with the same mappings as the given map. |
| 883 |
|
* |
| 884 |
< |
* @param initialCapacity the initial capacity. The implementation |
| 943 |
< |
* performs internal sizing to accommodate this many elements. |
| 944 |
< |
* @throws IllegalArgumentException if the initial capacity of |
| 945 |
< |
* elements is negative. |
| 884 |
> |
* @param m the map |
| 885 |
|
*/ |
| 886 |
< |
public ConcurrentHashMapV8(int initialCapacity) { |
| 887 |
< |
this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); |
| 886 |
> |
public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) { |
| 887 |
> |
this.counter = new LongAdder(); |
| 888 |
> |
this.targetCapacity = DEFAULT_CAPACITY; |
| 889 |
> |
putAll(m); |
| 890 |
|
} |
| 891 |
|
|
| 892 |
|
/** |
| 893 |
< |
* Creates a new, empty map with a default initial capacity (16), |
| 894 |
< |
* load factor (0.75) and concurrencyLevel (16). |
| 893 |
> |
* Creates a new, empty map with an initial table size based on |
| 894 |
> |
* the given number of elements ({@code initialCapacity}) and |
| 895 |
> |
* initial table density ({@code loadFactor}). |
| 896 |
> |
* |
| 897 |
> |
* @param initialCapacity the initial capacity. The implementation |
| 898 |
> |
* performs internal sizing to accommodate this many elements, |
| 899 |
> |
* given the specified load factor. |
| 900 |
> |
* @param loadFactor the load factor (table density) for |
| 901 |
> |
* establishing the initial table size |
| 902 |
> |
* @throws IllegalArgumentException if the initial capacity of |
| 903 |
> |
* elements is negative or the load factor is nonpositive |
| 904 |
> |
* |
| 905 |
> |
* @since 1.6 |
| 906 |
|
*/ |
| 907 |
< |
public ConcurrentHashMapV8() { |
| 908 |
< |
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); |
| 907 |
> |
public ConcurrentHashMapV8(int initialCapacity, float loadFactor) { |
| 908 |
> |
this(initialCapacity, loadFactor, 1); |
| 909 |
|
} |
| 910 |
|
|
| 911 |
|
/** |
| 912 |
< |
* Creates a new map with the same mappings as the given map. |
| 913 |
< |
* The map is created with a capacity of 1.5 times the number |
| 914 |
< |
* of mappings in the given map or 16 (whichever is greater), |
| 915 |
< |
* and a default load factor (0.75) and concurrencyLevel (16). |
| 912 |
> |
* Creates a new, empty map with an initial table size based on |
| 913 |
> |
* the given number of elements ({@code initialCapacity}), table |
| 914 |
> |
* density ({@code loadFactor}), and number of concurrently |
| 915 |
> |
* updating threads ({@code concurrencyLevel}). |
| 916 |
|
* |
| 917 |
< |
* @param m the map |
| 917 |
> |
* @param initialCapacity the initial capacity. The implementation |
| 918 |
> |
* performs internal sizing to accommodate this many elements, |
| 919 |
> |
* given the specified load factor. |
| 920 |
> |
* @param loadFactor the load factor (table density) for |
| 921 |
> |
* establishing the initial table size |
| 922 |
> |
* @param concurrencyLevel the estimated number of concurrently |
| 923 |
> |
* updating threads. The implementation may use this value as |
| 924 |
> |
* a sizing hint. |
| 925 |
> |
* @throws IllegalArgumentException if the initial capacity is |
| 926 |
> |
* negative or the load factor or concurrencyLevel are |
| 927 |
> |
* nonpositive |
| 928 |
|
*/ |
| 929 |
< |
public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) { |
| 930 |
< |
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); |
| 931 |
< |
if (m == null) |
| 932 |
< |
throw new NullPointerException(); |
| 933 |
< |
internalPutAll(m); |
| 929 |
> |
public ConcurrentHashMapV8(int initialCapacity, |
| 930 |
> |
float loadFactor, int concurrencyLevel) { |
| 931 |
> |
if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) |
| 932 |
> |
throw new IllegalArgumentException(); |
| 933 |
> |
if (initialCapacity < concurrencyLevel) // Use at least as many bins |
| 934 |
> |
initialCapacity = concurrencyLevel; // as estimated threads |
| 935 |
> |
long size = (long)(1.0 + (long)initialCapacity / loadFactor); |
| 936 |
> |
int cap = ((size >= (long)MAXIMUM_CAPACITY) ? |
| 937 |
> |
MAXIMUM_CAPACITY: tableSizeFor((int)size)); |
| 938 |
> |
this.counter = new LongAdder(); |
| 939 |
> |
this.targetCapacity = cap; |
| 940 |
|
} |
| 941 |
|
|
| 942 |
|
/** |
| 943 |
< |
* Returns {@code true} if this map contains no key-value mappings. |
| 976 |
< |
* |
| 977 |
< |
* @return {@code true} if this map contains no key-value mappings |
| 943 |
> |
* {@inheritDoc} |
| 944 |
|
*/ |
| 945 |
|
public boolean isEmpty() { |
| 946 |
|
return counter.sum() <= 0L; // ignore transient negative values |
| 947 |
|
} |
| 948 |
|
|
| 949 |
|
/** |
| 950 |
< |
* Returns the number of key-value mappings in this map. If the |
| 985 |
< |
* map contains more than {@code Integer.MAX_VALUE} elements, returns |
| 986 |
< |
* {@code Integer.MAX_VALUE}. |
| 987 |
< |
* |
| 988 |
< |
* @return the number of key-value mappings in this map |
| 950 |
> |
* {@inheritDoc} |
| 951 |
|
*/ |
| 952 |
|
public int size() { |
| 953 |
|
long n = counter.sum(); |
| 954 |
< |
return ((n >>> 31) == 0) ? (int)n : (n < 0L) ? 0 : Integer.MAX_VALUE; |
| 954 |
> |
return ((n < 0L) ? 0 : |
| 955 |
> |
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : |
| 956 |
> |
(int)n); |
| 957 |
|
} |
| 958 |
|
|
| 959 |
|
/** |
| 980 |
|
* @param key possible key |
| 981 |
|
* @return {@code true} if and only if the specified object |
| 982 |
|
* is a key in this table, as determined by the |
| 983 |
< |
* {@code equals} method; {@code false} otherwise. |
| 983 |
> |
* {@code equals} method; {@code false} otherwise |
| 984 |
|
* @throws NullPointerException if the specified key is null |
| 985 |
|
*/ |
| 986 |
|
public boolean containsKey(Object key) { |
| 991 |
|
|
| 992 |
|
/** |
| 993 |
|
* Returns {@code true} if this map maps one or more keys to the |
| 994 |
< |
* specified value. Note: This method requires a full internal |
| 995 |
< |
* traversal of the hash table, and so is much slower than |
| 1032 |
< |
* method {@code containsKey}. |
| 994 |
> |
* specified value. Note: This method may require a full traversal |
| 995 |
> |
* of the map, and is much slower than method {@code containsKey}. |
| 996 |
|
* |
| 997 |
|
* @param value value whose presence in this map is to be tested |
| 998 |
|
* @return {@code true} if this map maps one or more keys to the |
| 1002 |
|
public boolean containsValue(Object value) { |
| 1003 |
|
if (value == null) |
| 1004 |
|
throw new NullPointerException(); |
| 1005 |
< |
return new HashIterator().containsVal(value); |
| 1005 |
> |
Object v; |
| 1006 |
> |
InternalIterator it = new InternalIterator(table); |
| 1007 |
> |
while (it.next != null) { |
| 1008 |
> |
if ((v = it.nextVal) == value || value.equals(v)) |
| 1009 |
> |
return true; |
| 1010 |
> |
it.advance(); |
| 1011 |
> |
} |
| 1012 |
> |
return false; |
| 1013 |
|
} |
| 1014 |
|
|
| 1015 |
|
/** |
| 1075 |
|
public void putAll(Map<? extends K, ? extends V> m) { |
| 1076 |
|
if (m == null) |
| 1077 |
|
throw new NullPointerException(); |
| 1078 |
< |
internalPutAll(m); |
| 1078 |
> |
/* |
| 1079 |
> |
* If uninitialized, try to adjust targetCapacity to |
| 1080 |
> |
* accommodate the given number of elements. |
| 1081 |
> |
*/ |
| 1082 |
> |
if (table == null) { |
| 1083 |
> |
int size = m.size(); |
| 1084 |
> |
int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : |
| 1085 |
> |
tableSizeFor(size + (size >>> 1) + 1); |
| 1086 |
> |
if (cap > targetCapacity) |
| 1087 |
> |
targetCapacity = cap; |
| 1088 |
> |
} |
| 1089 |
> |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) |
| 1090 |
> |
put(e.getKey(), e.getValue()); |
| 1091 |
|
} |
| 1092 |
|
|
| 1093 |
|
/** |
| 1094 |
|
* If the specified key is not already associated with a value, |
| 1095 |
|
* computes its value using the given mappingFunction, and if |
| 1096 |
|
* non-null, enters it into the map. This is equivalent to |
| 1097 |
< |
* |
| 1098 |
< |
* <pre> |
| 1099 |
< |
* if (map.containsKey(key)) |
| 1100 |
< |
* return map.get(key); |
| 1101 |
< |
* value = mappingFunction.map(key); |
| 1102 |
< |
* if (value != null) |
| 1103 |
< |
* map.put(key, value); |
| 1122 |
< |
* return value; |
| 1123 |
< |
* </pre> |
| 1097 |
> |
* <pre> {@code |
| 1098 |
> |
* if (map.containsKey(key)) |
| 1099 |
> |
* return map.get(key); |
| 1100 |
> |
* value = mappingFunction.map(key); |
| 1101 |
> |
* if (value != null) |
| 1102 |
> |
* map.put(key, value); |
| 1103 |
> |
* return value;}</pre> |
| 1104 |
|
* |
| 1105 |
|
* except that the action is performed atomically. Some attempted |
| 1106 |
|
* update operations on this map by other threads may be blocked |
| 1109 |
|
* mappings of this Map. The most appropriate usage is to |
| 1110 |
|
* construct a new object serving as an initial mapped value, or |
| 1111 |
|
* memoized result, as in: |
| 1112 |
< |
* <pre>{@code |
| 1112 |
> |
* <pre> {@code |
| 1113 |
|
* map.computeIfAbsent(key, new MappingFunction<K, V>() { |
| 1114 |
< |
* public V map(K k) { return new Value(f(k)); }}; |
| 1135 |
< |
* }</pre> |
| 1114 |
> |
* public V map(K k) { return new Value(f(k)); }});}</pre> |
| 1115 |
|
* |
| 1116 |
|
* @param key key with which the specified value is to be associated |
| 1117 |
|
* @param mappingFunction the function to compute a value |
| 1118 |
|
* @return the current (existing or computed) value associated with |
| 1119 |
|
* the specified key, or {@code null} if the computation |
| 1120 |
< |
* returned {@code null}. |
| 1120 |
> |
* returned {@code null} |
| 1121 |
|
* @throws NullPointerException if the specified key or mappingFunction |
| 1122 |
< |
* is null, |
| 1122 |
> |
* is null |
| 1123 |
|
* @throws IllegalStateException if the computation detectably |
| 1124 |
|
* attempts a recursive update to this map that would |
| 1125 |
< |
* otherwise never complete. |
| 1125 |
> |
* otherwise never complete |
| 1126 |
|
* @throws RuntimeException or Error if the mappingFunction does so, |
| 1127 |
< |
* in which case the mapping is left unestablished. |
| 1127 |
> |
* in which case the mapping is left unestablished |
| 1128 |
|
*/ |
| 1129 |
|
public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
| 1130 |
|
if (key == null || mappingFunction == null) |
| 1136 |
|
* Computes the value associated with the given key using the given |
| 1137 |
|
* mappingFunction, and if non-null, enters it into the map. This |
| 1138 |
|
* is equivalent to |
| 1139 |
< |
* |
| 1140 |
< |
* <pre> |
| 1141 |
< |
* value = mappingFunction.map(key); |
| 1142 |
< |
* if (value != null) |
| 1143 |
< |
* map.put(key, value); |
| 1144 |
< |
* else |
| 1145 |
< |
* value = map.get(key); |
| 1167 |
< |
* return value; |
| 1168 |
< |
* </pre> |
| 1139 |
> |
* <pre> {@code |
| 1140 |
> |
* value = mappingFunction.map(key); |
| 1141 |
> |
* if (value != null) |
| 1142 |
> |
* map.put(key, value); |
| 1143 |
> |
* else |
| 1144 |
> |
* value = map.get(key); |
| 1145 |
> |
* return value;}</pre> |
| 1146 |
|
* |
| 1147 |
|
* except that the action is performed atomically. Some attempted |
| 1148 |
|
* update operations on this map by other threads may be blocked |
| 1154 |
|
* @param mappingFunction the function to compute a value |
| 1155 |
|
* @return the current value associated with |
| 1156 |
|
* the specified key, or {@code null} if the computation |
| 1157 |
< |
* returned {@code null} and the value was not otherwise present. |
| 1157 |
> |
* returned {@code null} and the value was not otherwise present |
| 1158 |
|
* @throws NullPointerException if the specified key or mappingFunction |
| 1159 |
< |
* is null, |
| 1159 |
> |
* is null |
| 1160 |
|
* @throws IllegalStateException if the computation detectably |
| 1161 |
|
* attempts a recursive update to this map that would |
| 1162 |
< |
* otherwise never complete. |
| 1162 |
> |
* otherwise never complete |
| 1163 |
|
* @throws RuntimeException or Error if the mappingFunction does so, |
| 1164 |
< |
* in which case the mapping is unchanged. |
| 1164 |
> |
* in which case the mapping is unchanged |
| 1165 |
|
*/ |
| 1166 |
|
public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
| 1167 |
|
if (key == null || mappingFunction == null) |
| 1247 |
|
* reflect any modifications subsequent to construction. |
| 1248 |
|
*/ |
| 1249 |
|
public Set<K> keySet() { |
| 1250 |
< |
Set<K> ks = keySet; |
| 1251 |
< |
return (ks != null) ? ks : (keySet = new KeySet()); |
| 1250 |
> |
KeySet<K,V> ks = keySet; |
| 1251 |
> |
return (ks != null) ? ks : (keySet = new KeySet<K,V>(this)); |
| 1252 |
|
} |
| 1253 |
|
|
| 1254 |
|
/** |
| 1268 |
|
* reflect any modifications subsequent to construction. |
| 1269 |
|
*/ |
| 1270 |
|
public Collection<V> values() { |
| 1271 |
< |
Collection<V> vs = values; |
| 1272 |
< |
return (vs != null) ? vs : (values = new Values()); |
| 1271 |
> |
Values<K,V> vs = values; |
| 1272 |
> |
return (vs != null) ? vs : (values = new Values<K,V>(this)); |
| 1273 |
|
} |
| 1274 |
|
|
| 1275 |
|
/** |
| 1289 |
|
* reflect any modifications subsequent to construction. |
| 1290 |
|
*/ |
| 1291 |
|
public Set<Map.Entry<K,V>> entrySet() { |
| 1292 |
< |
Set<Map.Entry<K,V>> es = entrySet; |
| 1293 |
< |
return (es != null) ? es : (entrySet = new EntrySet()); |
| 1292 |
> |
EntrySet<K,V> es = entrySet; |
| 1293 |
> |
return (es != null) ? es : (entrySet = new EntrySet<K,V>(this)); |
| 1294 |
|
} |
| 1295 |
|
|
| 1296 |
|
/** |
| 1300 |
|
* @see #keySet() |
| 1301 |
|
*/ |
| 1302 |
|
public Enumeration<K> keys() { |
| 1303 |
< |
return new KeyIterator(); |
| 1303 |
> |
return new KeyIterator<K,V>(this); |
| 1304 |
|
} |
| 1305 |
|
|
| 1306 |
|
/** |
| 1310 |
|
* @see #values() |
| 1311 |
|
*/ |
| 1312 |
|
public Enumeration<V> elements() { |
| 1313 |
< |
return new ValueIterator(); |
| 1313 |
> |
return new ValueIterator<K,V>(this); |
| 1314 |
|
} |
| 1315 |
|
|
| 1316 |
|
/** |
| 1321 |
|
* @return the hash code value for this map |
| 1322 |
|
*/ |
| 1323 |
|
public int hashCode() { |
| 1324 |
< |
return new HashIterator().mapHashCode(); |
| 1324 |
> |
int h = 0; |
| 1325 |
> |
InternalIterator it = new InternalIterator(table); |
| 1326 |
> |
while (it.next != null) { |
| 1327 |
> |
h += it.nextKey.hashCode() ^ it.nextVal.hashCode(); |
| 1328 |
> |
it.advance(); |
| 1329 |
> |
} |
| 1330 |
> |
return h; |
| 1331 |
|
} |
| 1332 |
|
|
| 1333 |
|
/** |
| 1342 |
|
* @return a string representation of this map |
| 1343 |
|
*/ |
| 1344 |
|
public String toString() { |
| 1345 |
< |
return new HashIterator().mapToString(); |
| 1345 |
> |
InternalIterator it = new InternalIterator(table); |
| 1346 |
> |
StringBuilder sb = new StringBuilder(); |
| 1347 |
> |
sb.append('{'); |
| 1348 |
> |
if (it.next != null) { |
| 1349 |
> |
for (;;) { |
| 1350 |
> |
Object k = it.nextKey, v = it.nextVal; |
| 1351 |
> |
sb.append(k == this ? "(this Map)" : k); |
| 1352 |
> |
sb.append('='); |
| 1353 |
> |
sb.append(v == this ? "(this Map)" : v); |
| 1354 |
> |
it.advance(); |
| 1355 |
> |
if (it.next == null) |
| 1356 |
> |
break; |
| 1357 |
> |
sb.append(',').append(' '); |
| 1358 |
> |
} |
| 1359 |
> |
} |
| 1360 |
> |
return sb.append('}').toString(); |
| 1361 |
|
} |
| 1362 |
|
|
| 1363 |
|
/** |
| 1371 |
|
* @return {@code true} if the specified object is equal to this map |
| 1372 |
|
*/ |
| 1373 |
|
public boolean equals(Object o) { |
| 1374 |
< |
if (o == this) |
| 1375 |
< |
return true; |
| 1376 |
< |
if (!(o instanceof Map)) |
| 1377 |
< |
return false; |
| 1378 |
< |
Map<?,?> m = (Map<?,?>) o; |
| 1379 |
< |
try { |
| 1380 |
< |
for (Map.Entry<K,V> e : this.entrySet()) |
| 1381 |
< |
if (! e.getValue().equals(m.get(e.getKey()))) |
| 1374 |
> |
if (o != this) { |
| 1375 |
> |
if (!(o instanceof Map)) |
| 1376 |
> |
return false; |
| 1377 |
> |
Map<?,?> m = (Map<?,?>) o; |
| 1378 |
> |
InternalIterator it = new InternalIterator(table); |
| 1379 |
> |
while (it.next != null) { |
| 1380 |
> |
Object val = it.nextVal; |
| 1381 |
> |
Object v = m.get(it.nextKey); |
| 1382 |
> |
if (v == null || (v != val && !v.equals(val))) |
| 1383 |
|
return false; |
| 1384 |
+ |
it.advance(); |
| 1385 |
+ |
} |
| 1386 |
|
for (Map.Entry<?,?> e : m.entrySet()) { |
| 1387 |
< |
Object k = e.getKey(); |
| 1388 |
< |
Object v = e.getValue(); |
| 1389 |
< |
if (k == null || v == null || !v.equals(get(k))) |
| 1387 |
> |
Object mk, mv, v; |
| 1388 |
> |
if ((mk = e.getKey()) == null || |
| 1389 |
> |
(mv = e.getValue()) == null || |
| 1390 |
> |
(v = internalGet(mk)) == null || |
| 1391 |
> |
(mv != v && !mv.equals(v))) |
| 1392 |
|
return false; |
| 1393 |
|
} |
| 1394 |
< |
return true; |
| 1395 |
< |
} catch (ClassCastException unused) { |
| 1396 |
< |
return false; |
| 1397 |
< |
} catch (NullPointerException unused) { |
| 1398 |
< |
return false; |
| 1394 |
> |
} |
| 1395 |
> |
return true; |
| 1396 |
> |
} |
| 1397 |
> |
|
| 1398 |
> |
/* ----------------Iterators -------------- */ |
| 1399 |
> |
|
| 1400 |
> |
/** |
| 1401 |
> |
* Base class for key, value, and entry iterators. Adds a map |
| 1402 |
> |
* reference to InternalIterator to support Iterator.remove. |
| 1403 |
> |
*/ |
| 1404 |
> |
static abstract class ViewIterator<K,V> extends InternalIterator { |
| 1405 |
> |
final ConcurrentHashMapV8<K, V> map; |
| 1406 |
> |
ViewIterator(ConcurrentHashMapV8<K, V> map) { |
| 1407 |
> |
super(map.table); |
| 1408 |
> |
this.map = map; |
| 1409 |
> |
} |
| 1410 |
> |
|
| 1411 |
> |
public final void remove() { |
| 1412 |
> |
if (last == null) |
| 1413 |
> |
throw new IllegalStateException(); |
| 1414 |
> |
map.remove(last.key); |
| 1415 |
> |
last = null; |
| 1416 |
> |
} |
| 1417 |
> |
|
| 1418 |
> |
public final boolean hasNext() { return next != null; } |
| 1419 |
> |
public final boolean hasMoreElements() { return next != null; } |
| 1420 |
> |
} |
| 1421 |
> |
|
| 1422 |
> |
static final class KeyIterator<K,V> extends ViewIterator<K,V> |
| 1423 |
> |
implements Iterator<K>, Enumeration<K> { |
| 1424 |
> |
KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
| 1425 |
> |
|
| 1426 |
> |
@SuppressWarnings("unchecked") |
| 1427 |
> |
public final K next() { |
| 1428 |
> |
if (next == null) |
| 1429 |
> |
throw new NoSuchElementException(); |
| 1430 |
> |
Object k = nextKey; |
| 1431 |
> |
advance(); |
| 1432 |
> |
return (K)k; |
| 1433 |
> |
} |
| 1434 |
> |
|
| 1435 |
> |
public final K nextElement() { return next(); } |
| 1436 |
> |
} |
| 1437 |
> |
|
| 1438 |
> |
static final class ValueIterator<K,V> extends ViewIterator<K,V> |
| 1439 |
> |
implements Iterator<V>, Enumeration<V> { |
| 1440 |
> |
ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
| 1441 |
> |
|
| 1442 |
> |
@SuppressWarnings("unchecked") |
| 1443 |
> |
public final V next() { |
| 1444 |
> |
if (next == null) |
| 1445 |
> |
throw new NoSuchElementException(); |
| 1446 |
> |
Object v = nextVal; |
| 1447 |
> |
advance(); |
| 1448 |
> |
return (V)v; |
| 1449 |
> |
} |
| 1450 |
> |
|
| 1451 |
> |
public final V nextElement() { return next(); } |
| 1452 |
> |
} |
| 1453 |
> |
|
| 1454 |
> |
static final class EntryIterator<K,V> extends ViewIterator<K,V> |
| 1455 |
> |
implements Iterator<Map.Entry<K,V>> { |
| 1456 |
> |
EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
| 1457 |
> |
|
| 1458 |
> |
@SuppressWarnings("unchecked") |
| 1459 |
> |
public final Map.Entry<K,V> next() { |
| 1460 |
> |
if (next == null) |
| 1461 |
> |
throw new NoSuchElementException(); |
| 1462 |
> |
Object k = nextKey; |
| 1463 |
> |
Object v = nextVal; |
| 1464 |
> |
advance(); |
| 1465 |
> |
return new WriteThroughEntry<K,V>(map, (K)k, (V)v); |
| 1466 |
|
} |
| 1467 |
|
} |
| 1468 |
|
|
| 1470 |
|
* Custom Entry class used by EntryIterator.next(), that relays |
| 1471 |
|
* setValue changes to the underlying map. |
| 1472 |
|
*/ |
| 1473 |
< |
final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> { |
| 1474 |
< |
@SuppressWarnings("unchecked") |
| 1475 |
< |
WriteThroughEntry(Object k, Object v) { |
| 1476 |
< |
super((K)k, (V)v); |
| 1473 |
> |
static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> { |
| 1474 |
> |
final ConcurrentHashMapV8<K, V> map; |
| 1475 |
> |
final K key; // non-null |
| 1476 |
> |
V val; // non-null |
| 1477 |
> |
WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) { |
| 1478 |
> |
this.map = map; this.key = key; this.val = val; |
| 1479 |
> |
} |
| 1480 |
> |
|
| 1481 |
> |
public final K getKey() { return key; } |
| 1482 |
> |
public final V getValue() { return val; } |
| 1483 |
> |
public final int hashCode() { return key.hashCode() ^ val.hashCode(); } |
| 1484 |
> |
public final String toString(){ return key + "=" + val; } |
| 1485 |
> |
|
| 1486 |
> |
public final boolean equals(Object o) { |
| 1487 |
> |
Object k, v; Map.Entry<?,?> e; |
| 1488 |
> |
return ((o instanceof Map.Entry) && |
| 1489 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
| 1490 |
> |
(v = e.getValue()) != null && |
| 1491 |
> |
(k == key || k.equals(key)) && |
| 1492 |
> |
(v == val || v.equals(val))); |
| 1493 |
|
} |
| 1494 |
|
|
| 1495 |
|
/** |
| 1501 |
|
* removed in which case the put will re-establish). We do not |
| 1502 |
|
* and cannot guarantee more. |
| 1503 |
|
*/ |
| 1504 |
< |
public V setValue(V value) { |
| 1504 |
> |
public final V setValue(V value) { |
| 1505 |
|
if (value == null) throw new NullPointerException(); |
| 1506 |
< |
V v = super.setValue(value); |
| 1507 |
< |
ConcurrentHashMapV8.this.put(getKey(), value); |
| 1506 |
> |
V v = val; |
| 1507 |
> |
val = value; |
| 1508 |
> |
map.put(key, value); |
| 1509 |
|
return v; |
| 1510 |
|
} |
| 1511 |
|
} |
| 1512 |
|
|
| 1513 |
< |
final class KeyIterator extends HashIterator |
| 1427 |
< |
implements Iterator<K>, Enumeration<K> { |
| 1428 |
< |
@SuppressWarnings("unchecked") |
| 1429 |
< |
public final K next() { return (K)super.nextKey(); } |
| 1430 |
< |
@SuppressWarnings("unchecked") |
| 1431 |
< |
public final K nextElement() { return (K)super.nextKey(); } |
| 1432 |
< |
} |
| 1513 |
> |
/* ----------------Views -------------- */ |
| 1514 |
|
|
| 1515 |
< |
final class ValueIterator extends HashIterator |
| 1516 |
< |
implements Iterator<V>, Enumeration<V> { |
| 1517 |
< |
@SuppressWarnings("unchecked") |
| 1518 |
< |
public final V next() { return (V)super.nextValue(); } |
| 1438 |
< |
@SuppressWarnings("unchecked") |
| 1439 |
< |
public final V nextElement() { return (V)super.nextValue(); } |
| 1440 |
< |
} |
| 1515 |
> |
/* |
| 1516 |
> |
* These currently just extend java.util.AbstractX classes, but |
| 1517 |
> |
* may need a new custom base to support partitioned traversal. |
| 1518 |
> |
*/ |
| 1519 |
|
|
| 1520 |
< |
final class EntryIterator extends HashIterator |
| 1521 |
< |
implements Iterator<Entry<K,V>> { |
| 1522 |
< |
public final Map.Entry<K,V> next() { return super.nextEntry(); } |
| 1445 |
< |
} |
| 1520 |
> |
static final class KeySet<K,V> extends AbstractSet<K> { |
| 1521 |
> |
final ConcurrentHashMapV8<K, V> map; |
| 1522 |
> |
KeySet(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
| 1523 |
|
|
| 1524 |
< |
final class KeySet extends AbstractSet<K> { |
| 1525 |
< |
public int size() { |
| 1526 |
< |
return ConcurrentHashMapV8.this.size(); |
| 1527 |
< |
} |
| 1528 |
< |
public boolean isEmpty() { |
| 1529 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
| 1530 |
< |
} |
| 1454 |
< |
public void clear() { |
| 1455 |
< |
ConcurrentHashMapV8.this.clear(); |
| 1456 |
< |
} |
| 1457 |
< |
public Iterator<K> iterator() { |
| 1458 |
< |
return new KeyIterator(); |
| 1459 |
< |
} |
| 1460 |
< |
public boolean contains(Object o) { |
| 1461 |
< |
return ConcurrentHashMapV8.this.containsKey(o); |
| 1462 |
< |
} |
| 1463 |
< |
public boolean remove(Object o) { |
| 1464 |
< |
return ConcurrentHashMapV8.this.remove(o) != null; |
| 1524 |
> |
public final int size() { return map.size(); } |
| 1525 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
| 1526 |
> |
public final void clear() { map.clear(); } |
| 1527 |
> |
public final boolean contains(Object o) { return map.containsKey(o); } |
| 1528 |
> |
public final boolean remove(Object o) { return map.remove(o) != null; } |
| 1529 |
> |
public final Iterator<K> iterator() { |
| 1530 |
> |
return new KeyIterator<K,V>(map); |
| 1531 |
|
} |
| 1532 |
|
} |
| 1533 |
|
|
| 1534 |
< |
final class Values extends AbstractCollection<V> { |
| 1535 |
< |
public int size() { |
| 1536 |
< |
return ConcurrentHashMapV8.this.size(); |
| 1537 |
< |
} |
| 1538 |
< |
public boolean isEmpty() { |
| 1539 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
| 1540 |
< |
} |
| 1541 |
< |
public void clear() { |
| 1542 |
< |
ConcurrentHashMapV8.this.clear(); |
| 1543 |
< |
} |
| 1478 |
< |
public Iterator<V> iterator() { |
| 1479 |
< |
return new ValueIterator(); |
| 1480 |
< |
} |
| 1481 |
< |
public boolean contains(Object o) { |
| 1482 |
< |
return ConcurrentHashMapV8.this.containsValue(o); |
| 1534 |
> |
static final class Values<K,V> extends AbstractCollection<V> { |
| 1535 |
> |
final ConcurrentHashMapV8<K, V> map; |
| 1536 |
> |
Values(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
| 1537 |
> |
|
| 1538 |
> |
public final int size() { return map.size(); } |
| 1539 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
| 1540 |
> |
public final void clear() { map.clear(); } |
| 1541 |
> |
public final boolean contains(Object o) { return map.containsValue(o); } |
| 1542 |
> |
public final Iterator<V> iterator() { |
| 1543 |
> |
return new ValueIterator<K,V>(map); |
| 1544 |
|
} |
| 1545 |
|
} |
| 1546 |
|
|
| 1547 |
< |
final class EntrySet extends AbstractSet<Map.Entry<K,V>> { |
| 1548 |
< |
public int size() { |
| 1549 |
< |
return ConcurrentHashMapV8.this.size(); |
| 1550 |
< |
} |
| 1551 |
< |
public boolean isEmpty() { |
| 1552 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
| 1553 |
< |
} |
| 1554 |
< |
public void clear() { |
| 1555 |
< |
ConcurrentHashMapV8.this.clear(); |
| 1495 |
< |
} |
| 1496 |
< |
public Iterator<Map.Entry<K,V>> iterator() { |
| 1497 |
< |
return new EntryIterator(); |
| 1547 |
> |
static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> { |
| 1548 |
> |
final ConcurrentHashMapV8<K, V> map; |
| 1549 |
> |
EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
| 1550 |
> |
|
| 1551 |
> |
public final int size() { return map.size(); } |
| 1552 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
| 1553 |
> |
public final void clear() { map.clear(); } |
| 1554 |
> |
public final Iterator<Map.Entry<K,V>> iterator() { |
| 1555 |
> |
return new EntryIterator<K,V>(map); |
| 1556 |
|
} |
| 1557 |
< |
public boolean contains(Object o) { |
| 1558 |
< |
if (!(o instanceof Map.Entry)) |
| 1559 |
< |
return false; |
| 1560 |
< |
Map.Entry<?,?> e = (Map.Entry<?,?>)o; |
| 1561 |
< |
V v = ConcurrentHashMapV8.this.get(e.getKey()); |
| 1562 |
< |
return v != null && v.equals(e.getValue()); |
| 1557 |
> |
|
| 1558 |
> |
public final boolean contains(Object o) { |
| 1559 |
> |
Object k, v, r; Map.Entry<?,?> e; |
| 1560 |
> |
return ((o instanceof Map.Entry) && |
| 1561 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
| 1562 |
> |
(r = map.get(k)) != null && |
| 1563 |
> |
(v = e.getValue()) != null && |
| 1564 |
> |
(v == r || v.equals(r))); |
| 1565 |
|
} |
| 1566 |
< |
public boolean remove(Object o) { |
| 1567 |
< |
if (!(o instanceof Map.Entry)) |
| 1568 |
< |
return false; |
| 1569 |
< |
Map.Entry<?,?> e = (Map.Entry<?,?>)o; |
| 1570 |
< |
return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue()); |
| 1566 |
> |
|
| 1567 |
> |
public final boolean remove(Object o) { |
| 1568 |
> |
Object k, v; Map.Entry<?,?> e; |
| 1569 |
> |
return ((o instanceof Map.Entry) && |
| 1570 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
| 1571 |
> |
(v = e.getValue()) != null && |
| 1572 |
> |
map.remove(k, v)); |
| 1573 |
|
} |
| 1574 |
|
} |
| 1575 |
|
|
| 1576 |
|
/* ---------------- Serialization Support -------------- */ |
| 1577 |
|
|
| 1578 |
|
/** |
| 1579 |
< |
* Helper class used in previous version, declared for the sake of |
| 1580 |
< |
* serialization compatibility |
| 1579 |
> |
* Stripped-down version of helper class used in previous version, |
| 1580 |
> |
* declared for the sake of serialization compatibility |
| 1581 |
|
*/ |
| 1582 |
< |
static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock |
| 1521 |
< |
implements Serializable { |
| 1582 |
> |
static class Segment<K,V> implements Serializable { |
| 1583 |
|
private static final long serialVersionUID = 2249069246763182397L; |
| 1584 |
|
final float loadFactor; |
| 1585 |
|
Segment(float lf) { this.loadFactor = lf; } |
| 1601 |
|
segments = (Segment<K,V>[]) |
| 1602 |
|
new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; |
| 1603 |
|
for (int i = 0; i < segments.length; ++i) |
| 1604 |
< |
segments[i] = new Segment<K,V>(loadFactor); |
| 1604 |
> |
segments[i] = new Segment<K,V>(LOAD_FACTOR); |
| 1605 |
|
} |
| 1606 |
|
s.defaultWriteObject(); |
| 1607 |
< |
new HashIterator().writeEntries(s); |
| 1607 |
> |
InternalIterator it = new InternalIterator(table); |
| 1608 |
> |
while (it.next != null) { |
| 1609 |
> |
s.writeObject(it.nextKey); |
| 1610 |
> |
s.writeObject(it.nextVal); |
| 1611 |
> |
it.advance(); |
| 1612 |
> |
} |
| 1613 |
|
s.writeObject(null); |
| 1614 |
|
s.writeObject(null); |
| 1615 |
|
segments = null; // throw away |
| 1616 |
|
} |
| 1617 |
|
|
| 1618 |
|
/** |
| 1619 |
< |
* Reconstitutes the instance from a |
| 1554 |
< |
* stream (i.e., deserializes it). |
| 1619 |
> |
* Reconstitutes the instance from a stream (that is, deserializes it). |
| 1620 |
|
* @param s the stream |
| 1621 |
|
*/ |
| 1622 |
|
@SuppressWarnings("unchecked") |
| 1623 |
|
private void readObject(java.io.ObjectInputStream s) |
| 1624 |
|
throws java.io.IOException, ClassNotFoundException { |
| 1625 |
|
s.defaultReadObject(); |
| 1561 |
– |
// find load factor in a segment, if one exists |
| 1562 |
– |
if (segments != null && segments.length != 0) |
| 1563 |
– |
this.loadFactor = segments[0].loadFactor; |
| 1564 |
– |
else |
| 1565 |
– |
this.loadFactor = DEFAULT_LOAD_FACTOR; |
| 1566 |
– |
this.initCap = DEFAULT_CAPACITY; |
| 1567 |
– |
LongAdder ct = new LongAdder(); // force final field write |
| 1568 |
– |
UNSAFE.putObjectVolatile(this, counterOffset, ct); |
| 1626 |
|
this.segments = null; // unneeded |
| 1627 |
< |
|
| 1628 |
< |
// Read the keys and values, and put the mappings in the table |
| 1627 |
> |
// initialize transient final field |
| 1628 |
> |
UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder()); |
| 1629 |
> |
this.targetCapacity = DEFAULT_CAPACITY; |
| 1630 |
> |
|
| 1631 |
> |
// Create all nodes, then place in table once size is known |
| 1632 |
> |
long size = 0L; |
| 1633 |
> |
Node p = null; |
| 1634 |
|
for (;;) { |
| 1635 |
< |
K key = (K) s.readObject(); |
| 1636 |
< |
V value = (V) s.readObject(); |
| 1637 |
< |
if (key == null) |
| 1635 |
> |
K k = (K) s.readObject(); |
| 1636 |
> |
V v = (V) s.readObject(); |
| 1637 |
> |
if (k != null && v != null) { |
| 1638 |
> |
p = new Node(spread(k.hashCode()), k, v, p); |
| 1639 |
> |
++size; |
| 1640 |
> |
} |
| 1641 |
> |
else |
| 1642 |
|
break; |
| 1643 |
< |
put(key, value); |
| 1643 |
> |
} |
| 1644 |
> |
if (p != null) { |
| 1645 |
> |
boolean init = false; |
| 1646 |
> |
if (resizing == 0 && |
| 1647 |
> |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
| 1648 |
> |
try { |
| 1649 |
> |
if (table == null) { |
| 1650 |
> |
init = true; |
| 1651 |
> |
int n; |
| 1652 |
> |
if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) |
| 1653 |
> |
n = MAXIMUM_CAPACITY; |
| 1654 |
> |
else { |
| 1655 |
> |
int sz = (int)size; |
| 1656 |
> |
n = tableSizeFor(sz + (sz >>> 1) + 1); |
| 1657 |
> |
} |
| 1658 |
> |
threshold = n - (n >>> 2) - THRESHOLD_OFFSET; |
| 1659 |
> |
Node[] tab = new Node[n]; |
| 1660 |
> |
int mask = n - 1; |
| 1661 |
> |
while (p != null) { |
| 1662 |
> |
int j = p.hash & mask; |
| 1663 |
> |
Node next = p.next; |
| 1664 |
> |
p.next = tabAt(tab, j); |
| 1665 |
> |
setTabAt(tab, j, p); |
| 1666 |
> |
p = next; |
| 1667 |
> |
} |
| 1668 |
> |
table = tab; |
| 1669 |
> |
counter.add(size); |
| 1670 |
> |
} |
| 1671 |
> |
} finally { |
| 1672 |
> |
resizing = 0; |
| 1673 |
> |
} |
| 1674 |
> |
} |
| 1675 |
> |
if (!init) { // Can only happen if unsafely published. |
| 1676 |
> |
while (p != null) { |
| 1677 |
> |
internalPut(p.key, p.val, true); |
| 1678 |
> |
p = p.next; |
| 1679 |
> |
} |
| 1680 |
> |
} |
| 1681 |
|
} |
| 1682 |
|
} |
| 1683 |
|
|
