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} |
85 |
|
* <p><em>jsr166e note: This class is a candidate replacement for |
86 |
|
* java.util.concurrent.ConcurrentHashMap.<em> |
87 |
|
* |
88 |
< |
* @since 1.5 |
88 |
> |
* @since 1.8 |
89 |
|
* @author Doug Lea |
90 |
|
* @param <K> the type of keys maintained by this map |
91 |
|
* @param <V> the type of mapped values |
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 sometimes 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 |
< |
/* ---------------- Access and update operations -------------- */ |
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 |
> |
/* ---------------- 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 |
|
|
369 |
– |
|
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 (;;) { |
376 |
< |
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) { |
549 |
> |
synchronized (e) { // lock the 1st node of bin list |
550 |
|
if (tabAt(tab, i) == e) { |
551 |
< |
validated = true; |
551 |
> |
validated = true; // retry if 1st already deleted |
552 |
|
for (Node first = e;;) { |
553 |
< |
Object ek, ev; |
554 |
< |
if (e.hash == h && |
555 |
< |
(ek = e.key) != null && |
395 |
< |
(ev = e.val) != null && |
396 |
< |
(k == ek || k.equals(ek))) { |
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; |
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 |
|
|
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) { |
606 |
|
do { |
607 |
|
Object ek, ev; |
608 |
|
if (e.hash == h && |
609 |
< |
(ek = e.key) != null && |
610 |
< |
(ev = e.val) != null && |
451 |
< |
(k == ek || k.equals(ek))) { |
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) { |
621 |
|
} |
622 |
|
break; |
623 |
|
} |
624 |
< |
pred = e; |
466 |
< |
} while ((e = e.next) != null); |
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 |
|
} |
476 |
– |
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, |
642 |
|
V val = null; |
643 |
|
boolean added = false; |
644 |
|
Node[] tab = table; |
645 |
< |
for(;;) { |
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 |
|
boolean validated = false; |
652 |
< |
synchronized (node) { |
652 |
> |
synchronized (node) { // must lock while computing value |
653 |
|
if (casTabAt(tab, i, null, node)) { |
654 |
|
validated = true; |
655 |
|
try { |
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 { |
685 |
|
if (tabAt(tab, i) == e) { |
686 |
|
validated = true; |
687 |
|
for (Node first = e;;) { |
524 |
– |
Object ek, ev, fv; |
688 |
|
if (e.hash == h && |
689 |
< |
(ek = e.key) != null && |
690 |
< |
(ev = e.val) != null && |
691 |
< |
(k == ek || k.equals(ek))) { |
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; |
709 |
|
} |
710 |
|
if (validated) { |
711 |
|
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
712 |
< |
resizing == 0 && counter.sum() >= threshold) |
713 |
< |
grow(0); |
712 |
> |
resizing == 0 && counter.sum() >= (long)threshold) |
713 |
> |
growTable(); |
714 |
|
break; |
715 |
|
} |
716 |
|
} |
720 |
|
return val; |
721 |
|
} |
722 |
|
|
560 |
– |
/* |
561 |
– |
* Reclassifies nodes in each bin to new table. Because we are |
562 |
– |
* using power-of-two expansion, the elements from each bin must |
563 |
– |
* either stay at same index, or move with a power of two |
564 |
– |
* offset. We eliminate unnecessary node creation by catching |
565 |
– |
* cases where old nodes can be reused because their next fields |
566 |
– |
* won't change. Statistically, at the default threshold, only |
567 |
– |
* about one-sixth of them need cloning when a table doubles. The |
568 |
– |
* nodes they replace will be garbage collectable as soon as they |
569 |
– |
* are no longer referenced by any reader thread that may be in |
570 |
– |
* the midst of concurrently traversing table. |
571 |
– |
* |
572 |
– |
* Transfers are done from the bottom up to preserve iterator |
573 |
– |
* traversability. On each step, the old bin is locked, |
574 |
– |
* moved/copied, and then replaced with a forwarding node. |
575 |
– |
*/ |
576 |
– |
private static final void transfer(Node[] tab, Node[] nextTab) { |
577 |
– |
int n = tab.length; |
578 |
– |
int mask = nextTab.length - 1; |
579 |
– |
Node fwd = new Node(MOVED, nextTab, null, null); |
580 |
– |
for (int i = n - 1; i >= 0; --i) { |
581 |
– |
for (Node e;;) { |
582 |
– |
if ((e = tabAt(tab, i)) == null) { |
583 |
– |
if (casTabAt(tab, i, e, fwd)) |
584 |
– |
break; |
585 |
– |
} |
586 |
– |
else { |
587 |
– |
int idx = e.hash & mask; |
588 |
– |
boolean validated = false; |
589 |
– |
synchronized (e) { |
590 |
– |
if (tabAt(tab, i) == e) { |
591 |
– |
validated = true; |
592 |
– |
Node lastRun = e; |
593 |
– |
for (Node p = e.next; p != null; p = p.next) { |
594 |
– |
int j = p.hash & mask; |
595 |
– |
if (j != idx) { |
596 |
– |
idx = j; |
597 |
– |
lastRun = p; |
598 |
– |
} |
599 |
– |
} |
600 |
– |
relaxedSetTabAt(nextTab, idx, lastRun); |
601 |
– |
for (Node p = e; p != lastRun; p = p.next) { |
602 |
– |
int h = p.hash; |
603 |
– |
int j = h & mask; |
604 |
– |
Node r = relaxedTabAt(nextTab, j); |
605 |
– |
relaxedSetTabAt(nextTab, j, |
606 |
– |
new Node(h, p.key, p.val, r)); |
607 |
– |
} |
608 |
– |
setTabAt(tab, i, fwd); |
609 |
– |
} |
610 |
– |
} |
611 |
– |
if (validated) |
612 |
– |
break; |
613 |
– |
} |
614 |
– |
} |
615 |
– |
} |
616 |
– |
} |
617 |
– |
|
618 |
– |
/** |
619 |
– |
* If not already resizing, initializes or creates next table and |
620 |
– |
* transfers bins. Rechecks occupancy after a transfer to see if |
621 |
– |
* another resize is already needed because resizings are lagging |
622 |
– |
* additions. |
623 |
– |
* |
624 |
– |
* @param sizeHint overridden capacity target (nonzero only from putAll) |
625 |
– |
* @return current table |
626 |
– |
*/ |
627 |
– |
private final Node[] grow(int sizeHint) { |
628 |
– |
if (resizing == 0 && |
629 |
– |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
630 |
– |
try { |
631 |
– |
for (;;) { |
632 |
– |
int cap, n; |
633 |
– |
Node[] tab = table; |
634 |
– |
if (tab == null) { |
635 |
– |
int c = initCap; |
636 |
– |
if (c < sizeHint) |
637 |
– |
c = sizeHint; |
638 |
– |
if (c == DEFAULT_CAPACITY) |
639 |
– |
cap = c; |
640 |
– |
else if (c >= MAXIMUM_CAPACITY) |
641 |
– |
cap = MAXIMUM_CAPACITY; |
642 |
– |
else { |
643 |
– |
cap = MINIMUM_CAPACITY; |
644 |
– |
while (cap < c) |
645 |
– |
cap <<= 1; |
646 |
– |
} |
647 |
– |
} |
648 |
– |
else if ((n = tab.length) < MAXIMUM_CAPACITY && |
649 |
– |
(sizeHint <= 0 || n < sizeHint)) |
650 |
– |
cap = n << 1; |
651 |
– |
else |
652 |
– |
break; |
653 |
– |
threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET; |
654 |
– |
Node[] nextTab = new Node[cap]; |
655 |
– |
if (tab != null) |
656 |
– |
transfer(tab, nextTab); |
657 |
– |
table = nextTab; |
658 |
– |
if (tab == null || cap >= MAXIMUM_CAPACITY || |
659 |
– |
((sizeHint > 0) ? cap >= sizeHint : |
660 |
– |
counter.sum() < threshold)) |
661 |
– |
break; |
662 |
– |
} |
663 |
– |
} finally { |
664 |
– |
resizing = 0; |
665 |
– |
} |
666 |
– |
} |
667 |
– |
else if (table == null) |
668 |
– |
Thread.yield(); // lost initialization race; just spin |
669 |
– |
return table; |
670 |
– |
} |
671 |
– |
|
672 |
– |
/** |
673 |
– |
* Implementation for putAll and constructor with Map |
674 |
– |
* argument. Tries to first override initial capacity or grow |
675 |
– |
* based on map size to pre-allocate table space. |
676 |
– |
*/ |
677 |
– |
private final void internalPutAll(Map<? extends K, ? extends V> m) { |
678 |
– |
int s = m.size(); |
679 |
– |
grow((s >= (MAXIMUM_CAPACITY >>> 1)) ? s : s + (s >>> 1)); |
680 |
– |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { |
681 |
– |
Object k = e.getKey(); |
682 |
– |
Object v = e.getValue(); |
683 |
– |
if (k == null || v == null) |
684 |
– |
throw new NullPointerException(); |
685 |
– |
internalPut(k, v, true); |
686 |
– |
} |
687 |
– |
} |
688 |
– |
|
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; |
718 |
– |
if (deletions > THRESHOLD_OFFSET) { // bound lag in counts |
719 |
– |
counter.add(-deletions); |
720 |
– |
deletions = 0L; |
721 |
– |
} |
722 |
– |
} |
754 |
|
} |
755 |
|
} |
756 |
< |
if (deletions != 0L) |
726 |
< |
counter.add(-deletions); |
756 |
> |
counter.add(delta); |
757 |
|
} |
758 |
|
|
759 |
< |
/** |
730 |
< |
* Base class for key, value, and entry iterators, plus internal |
731 |
< |
* implementations of public traversal-based methods, to avoid |
732 |
< |
* duplicating traversal code. |
733 |
< |
*/ |
734 |
< |
class HashIterator { |
735 |
< |
private Node next; // the next entry to return |
736 |
< |
private Node[] tab; // current table; updated if resized |
737 |
< |
private Node lastReturned; // the last entry returned, for remove |
738 |
< |
private Object nextVal; // cached value of next |
739 |
< |
private int index; // index of bin to use next |
740 |
< |
private int baseIndex; // current index of initial table |
741 |
< |
private final int baseSize; // initial table size |
742 |
< |
|
743 |
< |
HashIterator() { |
744 |
< |
Node[] t = tab = table; |
745 |
< |
if (t == null) |
746 |
< |
baseSize = 0; |
747 |
< |
else { |
748 |
< |
baseSize = t.length; |
749 |
< |
advance(null); |
750 |
< |
} |
751 |
< |
} |
752 |
< |
|
753 |
< |
public final boolean hasNext() { return next != null; } |
754 |
< |
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) { |
780 |
< |
tab = (Node[])e.key; |
781 |
< |
e = null; |
782 |
< |
} |
783 |
< |
else if (i + baseSize < t.length) |
784 |
< |
index += baseSize; // visit forwarded upper slots |
785 |
< |
else |
786 |
< |
index = ++baseIndex; |
787 |
< |
} |
788 |
< |
else { |
789 |
< |
next = null; |
790 |
< |
break; |
791 |
< |
} |
792 |
< |
} |
793 |
< |
} |
794 |
< |
|
795 |
< |
final Object nextKey() { |
796 |
< |
Node e = next; |
797 |
< |
if (e == null) |
798 |
< |
throw new NoSuchElementException(); |
799 |
< |
Object k = e.key; |
800 |
< |
advance((lastReturned = e).next); |
801 |
< |
return k; |
802 |
< |
} |
803 |
< |
|
804 |
< |
final Object nextValue() { |
805 |
< |
Node e = next; |
806 |
< |
if (e == null) |
807 |
< |
throw new NoSuchElementException(); |
808 |
< |
Object v = nextVal; |
809 |
< |
advance((lastReturned = e).next); |
810 |
< |
return v; |
811 |
< |
} |
812 |
< |
|
813 |
< |
final WriteThroughEntry nextEntry() { |
814 |
< |
Node e = next; |
815 |
< |
if (e == null) |
816 |
< |
throw new NoSuchElementException(); |
817 |
< |
WriteThroughEntry entry = |
818 |
< |
new WriteThroughEntry(e.key, nextVal); |
819 |
< |
advance((lastReturned = e).next); |
820 |
< |
return entry; |
821 |
< |
} |
822 |
< |
|
823 |
< |
public final void remove() { |
824 |
< |
if (lastReturned == null) |
825 |
< |
throw new IllegalStateException(); |
826 |
< |
ConcurrentHashMapV8.this.remove(lastReturned.key); |
827 |
< |
lastReturned = null; |
828 |
< |
} |
829 |
< |
|
830 |
< |
/** Helper for serialization */ |
831 |
< |
final void writeEntries(java.io.ObjectOutputStream s) |
832 |
< |
throws java.io.IOException { |
833 |
< |
Node e; |
834 |
< |
while ((e = next) != null) { |
835 |
< |
s.writeObject(e.key); |
836 |
< |
s.writeObject(nextVal); |
837 |
< |
advance(e.next); |
838 |
< |
} |
839 |
< |
} |
840 |
< |
|
841 |
< |
/** Helper for containsValue */ |
842 |
< |
final boolean containsVal(Object value) { |
843 |
< |
if (value != null) { |
844 |
< |
Node e; |
845 |
< |
while ((e = next) != null) { |
846 |
< |
Object v = nextVal; |
847 |
< |
if (value == v || value.equals(v)) |
848 |
< |
return true; |
849 |
< |
advance(e.next); |
850 |
< |
} |
851 |
< |
} |
852 |
< |
return false; |
853 |
< |
} |
854 |
< |
|
855 |
< |
/** Helper for Map.hashCode */ |
856 |
< |
final int mapHashCode() { |
857 |
< |
int h = 0; |
858 |
< |
Node e; |
859 |
< |
while ((e = next) != null) { |
860 |
< |
h += e.key.hashCode() ^ nextVal.hashCode(); |
861 |
< |
advance(e.next); |
862 |
< |
} |
863 |
< |
return h; |
864 |
< |
} |
865 |
< |
|
866 |
< |
/** Helper for Map.toString */ |
867 |
< |
final String mapToString() { |
868 |
< |
Node e = next; |
869 |
< |
if (e == null) |
870 |
< |
return "{}"; |
871 |
< |
StringBuilder sb = new StringBuilder(); |
872 |
< |
sb.append('{'); |
873 |
< |
for (;;) { |
874 |
< |
sb.append(e.key == this ? "(this Map)" : e.key); |
875 |
< |
sb.append('='); |
876 |
< |
sb.append(nextVal == this ? "(this Map)" : nextVal); |
877 |
< |
advance(e.next); |
878 |
< |
if ((e = next) != null) |
879 |
< |
sb.append(',').append(' '); |
880 |
< |
else |
881 |
< |
return sb.append('}').toString(); |
882 |
< |
} |
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 |
890 |
< |
* capacity, load factor and concurrency level. |
891 |
< |
* |
892 |
< |
* @param initialCapacity the initial capacity. The implementation |
893 |
< |
* performs internal sizing to accommodate this many elements. |
894 |
< |
* @param loadFactor the load factor threshold, used to control resizing. |
895 |
< |
* Resizing may be performed when the average number of elements per |
896 |
< |
* bin exceeds this threshold. |
897 |
< |
* @param concurrencyLevel the estimated number of concurrently |
898 |
< |
* updating threads. The implementation may use this value as |
899 |
< |
* a sizing hint. |
900 |
< |
* @throws IllegalArgumentException if the initial capacity is |
901 |
< |
* negative or the load factor or concurrencyLevel are |
902 |
< |
* nonpositive. |
854 |
> |
* Creates a new, empty map with the default initial table size (16), |
855 |
|
*/ |
856 |
< |
public ConcurrentHashMapV8(int initialCapacity, |
905 |
< |
float loadFactor, int concurrencyLevel) { |
906 |
< |
if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0) |
907 |
< |
throw new IllegalArgumentException(); |
908 |
< |
this.initCap = initialCapacity; |
909 |
< |
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. |
919 |
– |
* @param loadFactor the load factor threshold, used to control resizing. |
920 |
– |
* Resizing may be performed when the average number of elements per |
921 |
– |
* bin exceeds this threshold. |
868 |
|
* @throws IllegalArgumentException if the initial capacity of |
869 |
< |
* elements is negative or the load factor is nonpositive |
924 |
< |
* |
925 |
< |
* @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, |
933 |
< |
* 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 |
936 |
< |
* performs internal sizing to accommodate this many elements. |
937 |
< |
* @throws IllegalArgumentException if the initial capacity of |
938 |
< |
* 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 |
< |
public ConcurrentHashMapV8() { |
906 |
< |
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); |
905 |
> |
public ConcurrentHashMapV8(int initialCapacity, float loadFactor) { |
906 |
> |
this(initialCapacity, loadFactor, 1); |
907 |
|
} |
908 |
|
|
909 |
|
/** |
910 |
< |
* Creates a new map with the same mappings as the given map. |
911 |
< |
* The map is created with a capacity of 1.5 times the number |
912 |
< |
* of mappings in the given map or 16 (whichever is greater), |
913 |
< |
* and a default load factor (0.75) and concurrencyLevel (16). |
910 |
> |
* Creates a new, empty map with an initial table size based on |
911 |
> |
* the given number of elements ({@code initialCapacity}), table |
912 |
> |
* density ({@code loadFactor}), and number of concurrently |
913 |
> |
* updating threads ({@code concurrencyLevel}). |
914 |
|
* |
915 |
< |
* @param m the map |
915 |
> |
* @param initialCapacity the initial capacity. The implementation |
916 |
> |
* performs internal sizing to accommodate this many elements, |
917 |
> |
* given the specified load factor. |
918 |
> |
* @param loadFactor the load factor (table density) for |
919 |
> |
* establishing the initial table size |
920 |
> |
* @param concurrencyLevel the estimated number of concurrently |
921 |
> |
* updating threads. The implementation may use this value as |
922 |
> |
* a sizing hint. |
923 |
> |
* @throws IllegalArgumentException if the initial capacity is |
924 |
> |
* negative or the load factor or concurrencyLevel are |
925 |
> |
* nonpositive |
926 |
|
*/ |
927 |
< |
public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) { |
928 |
< |
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); |
929 |
< |
if (m == null) |
930 |
< |
throw new NullPointerException(); |
931 |
< |
internalPutAll(m); |
927 |
> |
public ConcurrentHashMapV8(int initialCapacity, |
928 |
> |
float loadFactor, int concurrencyLevel) { |
929 |
> |
if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) |
930 |
> |
throw new IllegalArgumentException(); |
931 |
> |
if (initialCapacity < concurrencyLevel) // Use at least as many bins |
932 |
> |
initialCapacity = concurrencyLevel; // as estimated threads |
933 |
> |
long size = (long)(1.0 + (long)initialCapacity / loadFactor); |
934 |
> |
int cap = ((size >= (long)MAXIMUM_CAPACITY) ? |
935 |
> |
MAXIMUM_CAPACITY: tableSizeFor((int)size)); |
936 |
> |
this.counter = new LongAdder(); |
937 |
> |
this.targetCapacity = cap; |
938 |
|
} |
939 |
|
|
940 |
|
/** |
941 |
< |
* Returns {@code true} if this map contains no key-value mappings. |
969 |
< |
* |
970 |
< |
* @return {@code true} if this map contains no key-value mappings |
941 |
> |
* {@inheritDoc} |
942 |
|
*/ |
943 |
|
public boolean isEmpty() { |
944 |
|
return counter.sum() <= 0L; // ignore transient negative values |
945 |
|
} |
946 |
|
|
947 |
|
/** |
948 |
< |
* Returns the number of key-value mappings in this map. If the |
978 |
< |
* map contains more than {@code Integer.MAX_VALUE} elements, returns |
979 |
< |
* {@code Integer.MAX_VALUE}. |
980 |
< |
* |
981 |
< |
* @return the number of key-value mappings in this map |
948 |
> |
* {@inheritDoc} |
949 |
|
*/ |
950 |
|
public int size() { |
951 |
|
long n = counter.sum(); |
952 |
< |
return ((n >>> 31) == 0) ? (int)n : (n < 0L) ? 0 : Integer.MAX_VALUE; |
952 |
> |
return ((n < 0L) ? 0 : |
953 |
> |
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : |
954 |
> |
(int)n); |
955 |
|
} |
956 |
|
|
957 |
|
/** |
978 |
|
* @param key possible key |
979 |
|
* @return {@code true} if and only if the specified object |
980 |
|
* is a key in this table, as determined by the |
981 |
< |
* {@code equals} method; {@code false} otherwise. |
981 |
> |
* {@code equals} method; {@code false} otherwise |
982 |
|
* @throws NullPointerException if the specified key is null |
983 |
|
*/ |
984 |
|
public boolean containsKey(Object key) { |
989 |
|
|
990 |
|
/** |
991 |
|
* Returns {@code true} if this map maps one or more keys to the |
992 |
< |
* specified value. Note: This method requires a full internal |
993 |
< |
* traversal of the hash table, and so is much slower than |
1025 |
< |
* method {@code containsKey}. |
992 |
> |
* specified value. Note: This method may require a full traversal |
993 |
> |
* of the map, and is much slower than method {@code containsKey}. |
994 |
|
* |
995 |
|
* @param value value whose presence in this map is to be tested |
996 |
|
* @return {@code true} if this map maps one or more keys to the |
1000 |
|
public boolean containsValue(Object value) { |
1001 |
|
if (value == null) |
1002 |
|
throw new NullPointerException(); |
1003 |
< |
return new HashIterator().containsVal(value); |
1003 |
> |
Object v; |
1004 |
> |
InternalIterator it = new InternalIterator(table); |
1005 |
> |
while (it.next != null) { |
1006 |
> |
if ((v = it.nextVal) == value || value.equals(v)) |
1007 |
> |
return true; |
1008 |
> |
it.advance(); |
1009 |
> |
} |
1010 |
> |
return false; |
1011 |
|
} |
1012 |
|
|
1013 |
|
/** |
1073 |
|
public void putAll(Map<? extends K, ? extends V> m) { |
1074 |
|
if (m == null) |
1075 |
|
throw new NullPointerException(); |
1076 |
< |
internalPutAll(m); |
1076 |
> |
/* |
1077 |
> |
* If uninitialized, try to adjust targetCapacity to |
1078 |
> |
* accommodate the given number of elements. |
1079 |
> |
*/ |
1080 |
> |
if (table == null) { |
1081 |
> |
int size = m.size(); |
1082 |
> |
int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : |
1083 |
> |
tableSizeFor(size + (size >>> 1) + 1); |
1084 |
> |
if (cap > targetCapacity) |
1085 |
> |
targetCapacity = cap; |
1086 |
> |
} |
1087 |
> |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) |
1088 |
> |
put(e.getKey(), e.getValue()); |
1089 |
|
} |
1090 |
|
|
1091 |
|
/** |
1092 |
|
* If the specified key is not already associated with a value, |
1093 |
|
* computes its value using the given mappingFunction, and if |
1094 |
|
* non-null, enters it into the map. This is equivalent to |
1095 |
< |
* |
1096 |
< |
* <pre> |
1097 |
< |
* if (map.containsKey(key)) |
1098 |
< |
* return map.get(key); |
1099 |
< |
* value = mappingFunction.map(key); |
1100 |
< |
* if (value != null) |
1101 |
< |
* map.put(key, value); |
1115 |
< |
* return value; |
1116 |
< |
* </pre> |
1095 |
> |
* <pre> {@code |
1096 |
> |
* if (map.containsKey(key)) |
1097 |
> |
* return map.get(key); |
1098 |
> |
* value = mappingFunction.map(key); |
1099 |
> |
* if (value != null) |
1100 |
> |
* map.put(key, value); |
1101 |
> |
* return value;}</pre> |
1102 |
|
* |
1103 |
|
* except that the action is performed atomically. Some attempted |
1104 |
|
* update operations on this map by other threads may be blocked |
1107 |
|
* mappings of this Map. The most appropriate usage is to |
1108 |
|
* construct a new object serving as an initial mapped value, or |
1109 |
|
* memoized result, as in: |
1110 |
< |
* <pre>{@code |
1110 |
> |
* <pre> {@code |
1111 |
|
* map.computeIfAbsent(key, new MappingFunction<K, V>() { |
1112 |
< |
* public V map(K k) { return new Value(f(k)); }}; |
1128 |
< |
* }</pre> |
1112 |
> |
* public V map(K k) { return new Value(f(k)); }});}</pre> |
1113 |
|
* |
1114 |
|
* @param key key with which the specified value is to be associated |
1115 |
|
* @param mappingFunction the function to compute a value |
1116 |
|
* @return the current (existing or computed) value associated with |
1117 |
|
* the specified key, or {@code null} if the computation |
1118 |
< |
* returned {@code null}. |
1118 |
> |
* returned {@code null} |
1119 |
|
* @throws NullPointerException if the specified key or mappingFunction |
1120 |
< |
* is null, |
1120 |
> |
* is null |
1121 |
|
* @throws IllegalStateException if the computation detectably |
1122 |
|
* attempts a recursive update to this map that would |
1123 |
< |
* otherwise never complete. |
1123 |
> |
* otherwise never complete |
1124 |
|
* @throws RuntimeException or Error if the mappingFunction does so, |
1125 |
< |
* in which case the mapping is left unestablished. |
1125 |
> |
* in which case the mapping is left unestablished |
1126 |
|
*/ |
1127 |
|
public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
1128 |
|
if (key == null || mappingFunction == null) |
1134 |
|
* Computes the value associated with the given key using the given |
1135 |
|
* mappingFunction, and if non-null, enters it into the map. This |
1136 |
|
* is equivalent to |
1137 |
< |
* |
1138 |
< |
* <pre> |
1139 |
< |
* value = mappingFunction.map(key); |
1140 |
< |
* if (value != null) |
1141 |
< |
* map.put(key, value); |
1142 |
< |
* else |
1143 |
< |
* value = map.get(key); |
1160 |
< |
* return value; |
1161 |
< |
* </pre> |
1137 |
> |
* <pre> {@code |
1138 |
> |
* value = mappingFunction.map(key); |
1139 |
> |
* if (value != null) |
1140 |
> |
* map.put(key, value); |
1141 |
> |
* else |
1142 |
> |
* value = map.get(key); |
1143 |
> |
* return value;}</pre> |
1144 |
|
* |
1145 |
|
* except that the action is performed atomically. Some attempted |
1146 |
|
* update operations on this map by other threads may be blocked |
1152 |
|
* @param mappingFunction the function to compute a value |
1153 |
|
* @return the current value associated with |
1154 |
|
* the specified key, or {@code null} if the computation |
1155 |
< |
* returned {@code null} and the value was not otherwise present. |
1155 |
> |
* returned {@code null} and the value was not otherwise present |
1156 |
|
* @throws NullPointerException if the specified key or mappingFunction |
1157 |
< |
* is null, |
1157 |
> |
* is null |
1158 |
|
* @throws IllegalStateException if the computation detectably |
1159 |
|
* attempts a recursive update to this map that would |
1160 |
< |
* otherwise never complete. |
1160 |
> |
* otherwise never complete |
1161 |
|
* @throws RuntimeException or Error if the mappingFunction does so, |
1162 |
< |
* in which case the mapping is unchanged. |
1162 |
> |
* in which case the mapping is unchanged |
1163 |
|
*/ |
1164 |
|
public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) { |
1165 |
|
if (key == null || mappingFunction == null) |
1245 |
|
* reflect any modifications subsequent to construction. |
1246 |
|
*/ |
1247 |
|
public Set<K> keySet() { |
1248 |
< |
Set<K> ks = keySet; |
1249 |
< |
return (ks != null) ? ks : (keySet = new KeySet()); |
1248 |
> |
KeySet<K,V> ks = keySet; |
1249 |
> |
return (ks != null) ? ks : (keySet = new KeySet<K,V>(this)); |
1250 |
|
} |
1251 |
|
|
1252 |
|
/** |
1266 |
|
* reflect any modifications subsequent to construction. |
1267 |
|
*/ |
1268 |
|
public Collection<V> values() { |
1269 |
< |
Collection<V> vs = values; |
1270 |
< |
return (vs != null) ? vs : (values = new Values()); |
1269 |
> |
Values<K,V> vs = values; |
1270 |
> |
return (vs != null) ? vs : (values = new Values<K,V>(this)); |
1271 |
|
} |
1272 |
|
|
1273 |
|
/** |
1287 |
|
* reflect any modifications subsequent to construction. |
1288 |
|
*/ |
1289 |
|
public Set<Map.Entry<K,V>> entrySet() { |
1290 |
< |
Set<Map.Entry<K,V>> es = entrySet; |
1291 |
< |
return (es != null) ? es : (entrySet = new EntrySet()); |
1290 |
> |
EntrySet<K,V> es = entrySet; |
1291 |
> |
return (es != null) ? es : (entrySet = new EntrySet<K,V>(this)); |
1292 |
|
} |
1293 |
|
|
1294 |
|
/** |
1298 |
|
* @see #keySet() |
1299 |
|
*/ |
1300 |
|
public Enumeration<K> keys() { |
1301 |
< |
return new KeyIterator(); |
1301 |
> |
return new KeyIterator<K,V>(this); |
1302 |
|
} |
1303 |
|
|
1304 |
|
/** |
1308 |
|
* @see #values() |
1309 |
|
*/ |
1310 |
|
public Enumeration<V> elements() { |
1311 |
< |
return new ValueIterator(); |
1311 |
> |
return new ValueIterator<K,V>(this); |
1312 |
|
} |
1313 |
|
|
1314 |
|
/** |
1319 |
|
* @return the hash code value for this map |
1320 |
|
*/ |
1321 |
|
public int hashCode() { |
1322 |
< |
return new HashIterator().mapHashCode(); |
1322 |
> |
int h = 0; |
1323 |
> |
InternalIterator it = new InternalIterator(table); |
1324 |
> |
while (it.next != null) { |
1325 |
> |
h += it.nextKey.hashCode() ^ it.nextVal.hashCode(); |
1326 |
> |
it.advance(); |
1327 |
> |
} |
1328 |
> |
return h; |
1329 |
|
} |
1330 |
|
|
1331 |
|
/** |
1340 |
|
* @return a string representation of this map |
1341 |
|
*/ |
1342 |
|
public String toString() { |
1343 |
< |
return new HashIterator().mapToString(); |
1343 |
> |
InternalIterator it = new InternalIterator(table); |
1344 |
> |
StringBuilder sb = new StringBuilder(); |
1345 |
> |
sb.append('{'); |
1346 |
> |
if (it.next != null) { |
1347 |
> |
for (;;) { |
1348 |
> |
Object k = it.nextKey, v = it.nextVal; |
1349 |
> |
sb.append(k == this ? "(this Map)" : k); |
1350 |
> |
sb.append('='); |
1351 |
> |
sb.append(v == this ? "(this Map)" : v); |
1352 |
> |
it.advance(); |
1353 |
> |
if (it.next == null) |
1354 |
> |
break; |
1355 |
> |
sb.append(',').append(' '); |
1356 |
> |
} |
1357 |
> |
} |
1358 |
> |
return sb.append('}').toString(); |
1359 |
|
} |
1360 |
|
|
1361 |
|
/** |
1369 |
|
* @return {@code true} if the specified object is equal to this map |
1370 |
|
*/ |
1371 |
|
public boolean equals(Object o) { |
1372 |
< |
if (o == this) |
1373 |
< |
return true; |
1374 |
< |
if (!(o instanceof Map)) |
1375 |
< |
return false; |
1376 |
< |
Map<?,?> m = (Map<?,?>) o; |
1377 |
< |
try { |
1378 |
< |
for (Map.Entry<K,V> e : this.entrySet()) |
1379 |
< |
if (! e.getValue().equals(m.get(e.getKey()))) |
1372 |
> |
if (o != this) { |
1373 |
> |
if (!(o instanceof Map)) |
1374 |
> |
return false; |
1375 |
> |
Map<?,?> m = (Map<?,?>) o; |
1376 |
> |
InternalIterator it = new InternalIterator(table); |
1377 |
> |
while (it.next != null) { |
1378 |
> |
Object val = it.nextVal; |
1379 |
> |
Object v = m.get(it.nextKey); |
1380 |
> |
if (v == null || (v != val && !v.equals(val))) |
1381 |
|
return false; |
1382 |
+ |
it.advance(); |
1383 |
+ |
} |
1384 |
|
for (Map.Entry<?,?> e : m.entrySet()) { |
1385 |
< |
Object k = e.getKey(); |
1386 |
< |
Object v = e.getValue(); |
1387 |
< |
if (k == null || v == null || !v.equals(get(k))) |
1385 |
> |
Object mk, mv, v; |
1386 |
> |
if ((mk = e.getKey()) == null || |
1387 |
> |
(mv = e.getValue()) == null || |
1388 |
> |
(v = internalGet(mk)) == null || |
1389 |
> |
(mv != v && !mv.equals(v))) |
1390 |
|
return false; |
1391 |
|
} |
1392 |
< |
return true; |
1393 |
< |
} catch (ClassCastException unused) { |
1394 |
< |
return false; |
1395 |
< |
} catch (NullPointerException unused) { |
1396 |
< |
return false; |
1392 |
> |
} |
1393 |
> |
return true; |
1394 |
> |
} |
1395 |
> |
|
1396 |
> |
/* ----------------Iterators -------------- */ |
1397 |
> |
|
1398 |
> |
/** |
1399 |
> |
* Base class for key, value, and entry iterators. Adds a map |
1400 |
> |
* reference to InternalIterator to support Iterator.remove. |
1401 |
> |
*/ |
1402 |
> |
static abstract class ViewIterator<K,V> extends InternalIterator { |
1403 |
> |
final ConcurrentHashMapV8<K, V> map; |
1404 |
> |
ViewIterator(ConcurrentHashMapV8<K, V> map) { |
1405 |
> |
super(map.table); |
1406 |
> |
this.map = map; |
1407 |
> |
} |
1408 |
> |
|
1409 |
> |
public final void remove() { |
1410 |
> |
if (last == null) |
1411 |
> |
throw new IllegalStateException(); |
1412 |
> |
map.remove(last.key); |
1413 |
> |
last = null; |
1414 |
> |
} |
1415 |
> |
|
1416 |
> |
public final boolean hasNext() { return next != null; } |
1417 |
> |
public final boolean hasMoreElements() { return next != null; } |
1418 |
> |
} |
1419 |
> |
|
1420 |
> |
static final class KeyIterator<K,V> extends ViewIterator<K,V> |
1421 |
> |
implements Iterator<K>, Enumeration<K> { |
1422 |
> |
KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1423 |
> |
|
1424 |
> |
@SuppressWarnings("unchecked") |
1425 |
> |
public final K next() { |
1426 |
> |
if (next == null) |
1427 |
> |
throw new NoSuchElementException(); |
1428 |
> |
Object k = nextKey; |
1429 |
> |
advance(); |
1430 |
> |
return (K)k; |
1431 |
> |
} |
1432 |
> |
|
1433 |
> |
public final K nextElement() { return next(); } |
1434 |
> |
} |
1435 |
> |
|
1436 |
> |
static final class ValueIterator<K,V> extends ViewIterator<K,V> |
1437 |
> |
implements Iterator<V>, Enumeration<V> { |
1438 |
> |
ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1439 |
> |
|
1440 |
> |
@SuppressWarnings("unchecked") |
1441 |
> |
public final V next() { |
1442 |
> |
if (next == null) |
1443 |
> |
throw new NoSuchElementException(); |
1444 |
> |
Object v = nextVal; |
1445 |
> |
advance(); |
1446 |
> |
return (V)v; |
1447 |
> |
} |
1448 |
> |
|
1449 |
> |
public final V nextElement() { return next(); } |
1450 |
> |
} |
1451 |
> |
|
1452 |
> |
static final class EntryIterator<K,V> extends ViewIterator<K,V> |
1453 |
> |
implements Iterator<Map.Entry<K,V>> { |
1454 |
> |
EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1455 |
> |
|
1456 |
> |
@SuppressWarnings("unchecked") |
1457 |
> |
public final Map.Entry<K,V> next() { |
1458 |
> |
if (next == null) |
1459 |
> |
throw new NoSuchElementException(); |
1460 |
> |
Object k = nextKey; |
1461 |
> |
Object v = nextVal; |
1462 |
> |
advance(); |
1463 |
> |
return new WriteThroughEntry<K,V>(map, (K)k, (V)v); |
1464 |
|
} |
1465 |
|
} |
1466 |
|
|
1468 |
|
* Custom Entry class used by EntryIterator.next(), that relays |
1469 |
|
* setValue changes to the underlying map. |
1470 |
|
*/ |
1471 |
< |
final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> { |
1472 |
< |
@SuppressWarnings("unchecked") |
1473 |
< |
WriteThroughEntry(Object k, Object v) { |
1474 |
< |
super((K)k, (V)v); |
1471 |
> |
static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> { |
1472 |
> |
final ConcurrentHashMapV8<K, V> map; |
1473 |
> |
final K key; // non-null |
1474 |
> |
V val; // non-null |
1475 |
> |
WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) { |
1476 |
> |
this.map = map; this.key = key; this.val = val; |
1477 |
> |
} |
1478 |
> |
|
1479 |
> |
public final K getKey() { return key; } |
1480 |
> |
public final V getValue() { return val; } |
1481 |
> |
public final int hashCode() { return key.hashCode() ^ val.hashCode(); } |
1482 |
> |
public final String toString(){ return key + "=" + val; } |
1483 |
> |
|
1484 |
> |
public final boolean equals(Object o) { |
1485 |
> |
Object k, v; Map.Entry<?,?> e; |
1486 |
> |
return ((o instanceof Map.Entry) && |
1487 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1488 |
> |
(v = e.getValue()) != null && |
1489 |
> |
(k == key || k.equals(key)) && |
1490 |
> |
(v == val || v.equals(val))); |
1491 |
|
} |
1492 |
|
|
1493 |
|
/** |
1499 |
|
* removed in which case the put will re-establish). We do not |
1500 |
|
* and cannot guarantee more. |
1501 |
|
*/ |
1502 |
< |
public V setValue(V value) { |
1502 |
> |
public final V setValue(V value) { |
1503 |
|
if (value == null) throw new NullPointerException(); |
1504 |
< |
V v = super.setValue(value); |
1505 |
< |
ConcurrentHashMapV8.this.put(getKey(), value); |
1504 |
> |
V v = val; |
1505 |
> |
val = value; |
1506 |
> |
map.put(key, value); |
1507 |
|
return v; |
1508 |
|
} |
1509 |
|
} |
1510 |
|
|
1511 |
< |
final class KeyIterator extends HashIterator |
1420 |
< |
implements Iterator<K>, Enumeration<K> { |
1421 |
< |
@SuppressWarnings("unchecked") |
1422 |
< |
public final K next() { return (K)super.nextKey(); } |
1423 |
< |
@SuppressWarnings("unchecked") |
1424 |
< |
public final K nextElement() { return (K)super.nextKey(); } |
1425 |
< |
} |
1511 |
> |
/* ----------------Views -------------- */ |
1512 |
|
|
1513 |
< |
final class ValueIterator extends HashIterator |
1514 |
< |
implements Iterator<V>, Enumeration<V> { |
1515 |
< |
@SuppressWarnings("unchecked") |
1516 |
< |
public final V next() { return (V)super.nextValue(); } |
1431 |
< |
@SuppressWarnings("unchecked") |
1432 |
< |
public final V nextElement() { return (V)super.nextValue(); } |
1433 |
< |
} |
1513 |
> |
/* |
1514 |
> |
* These currently just extend java.util.AbstractX classes, but |
1515 |
> |
* may need a new custom base to support partitioned traversal. |
1516 |
> |
*/ |
1517 |
|
|
1518 |
< |
final class EntryIterator extends HashIterator |
1519 |
< |
implements Iterator<Entry<K,V>> { |
1520 |
< |
public final Map.Entry<K,V> next() { return super.nextEntry(); } |
1438 |
< |
} |
1518 |
> |
static final class KeySet<K,V> extends AbstractSet<K> { |
1519 |
> |
final ConcurrentHashMapV8<K, V> map; |
1520 |
> |
KeySet(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1521 |
|
|
1522 |
< |
final class KeySet extends AbstractSet<K> { |
1523 |
< |
public int size() { |
1524 |
< |
return ConcurrentHashMapV8.this.size(); |
1525 |
< |
} |
1526 |
< |
public boolean isEmpty() { |
1527 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
1528 |
< |
} |
1447 |
< |
public void clear() { |
1448 |
< |
ConcurrentHashMapV8.this.clear(); |
1449 |
< |
} |
1450 |
< |
public Iterator<K> iterator() { |
1451 |
< |
return new KeyIterator(); |
1452 |
< |
} |
1453 |
< |
public boolean contains(Object o) { |
1454 |
< |
return ConcurrentHashMapV8.this.containsKey(o); |
1455 |
< |
} |
1456 |
< |
public boolean remove(Object o) { |
1457 |
< |
return ConcurrentHashMapV8.this.remove(o) != null; |
1522 |
> |
public final int size() { return map.size(); } |
1523 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
1524 |
> |
public final void clear() { map.clear(); } |
1525 |
> |
public final boolean contains(Object o) { return map.containsKey(o); } |
1526 |
> |
public final boolean remove(Object o) { return map.remove(o) != null; } |
1527 |
> |
public final Iterator<K> iterator() { |
1528 |
> |
return new KeyIterator<K,V>(map); |
1529 |
|
} |
1530 |
|
} |
1531 |
|
|
1532 |
< |
final class Values extends AbstractCollection<V> { |
1533 |
< |
public int size() { |
1534 |
< |
return ConcurrentHashMapV8.this.size(); |
1535 |
< |
} |
1536 |
< |
public boolean isEmpty() { |
1537 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
1538 |
< |
} |
1539 |
< |
public void clear() { |
1540 |
< |
ConcurrentHashMapV8.this.clear(); |
1541 |
< |
} |
1471 |
< |
public Iterator<V> iterator() { |
1472 |
< |
return new ValueIterator(); |
1473 |
< |
} |
1474 |
< |
public boolean contains(Object o) { |
1475 |
< |
return ConcurrentHashMapV8.this.containsValue(o); |
1532 |
> |
static final class Values<K,V> extends AbstractCollection<V> { |
1533 |
> |
final ConcurrentHashMapV8<K, V> map; |
1534 |
> |
Values(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1535 |
> |
|
1536 |
> |
public final int size() { return map.size(); } |
1537 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
1538 |
> |
public final void clear() { map.clear(); } |
1539 |
> |
public final boolean contains(Object o) { return map.containsValue(o); } |
1540 |
> |
public final Iterator<V> iterator() { |
1541 |
> |
return new ValueIterator<K,V>(map); |
1542 |
|
} |
1543 |
|
} |
1544 |
|
|
1545 |
< |
final class EntrySet extends AbstractSet<Map.Entry<K,V>> { |
1546 |
< |
public int size() { |
1547 |
< |
return ConcurrentHashMapV8.this.size(); |
1548 |
< |
} |
1549 |
< |
public boolean isEmpty() { |
1550 |
< |
return ConcurrentHashMapV8.this.isEmpty(); |
1551 |
< |
} |
1552 |
< |
public void clear() { |
1553 |
< |
ConcurrentHashMapV8.this.clear(); |
1488 |
< |
} |
1489 |
< |
public Iterator<Map.Entry<K,V>> iterator() { |
1490 |
< |
return new EntryIterator(); |
1545 |
> |
static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> { |
1546 |
> |
final ConcurrentHashMapV8<K, V> map; |
1547 |
> |
EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1548 |
> |
|
1549 |
> |
public final int size() { return map.size(); } |
1550 |
> |
public final boolean isEmpty() { return map.isEmpty(); } |
1551 |
> |
public final void clear() { map.clear(); } |
1552 |
> |
public final Iterator<Map.Entry<K,V>> iterator() { |
1553 |
> |
return new EntryIterator<K,V>(map); |
1554 |
|
} |
1555 |
< |
public boolean contains(Object o) { |
1556 |
< |
if (!(o instanceof Map.Entry)) |
1557 |
< |
return false; |
1558 |
< |
Map.Entry<?,?> e = (Map.Entry<?,?>)o; |
1559 |
< |
V v = ConcurrentHashMapV8.this.get(e.getKey()); |
1560 |
< |
return v != null && v.equals(e.getValue()); |
1555 |
> |
|
1556 |
> |
public final boolean contains(Object o) { |
1557 |
> |
Object k, v, r; Map.Entry<?,?> e; |
1558 |
> |
return ((o instanceof Map.Entry) && |
1559 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1560 |
> |
(r = map.get(k)) != null && |
1561 |
> |
(v = e.getValue()) != null && |
1562 |
> |
(v == r || v.equals(r))); |
1563 |
|
} |
1564 |
< |
public boolean remove(Object o) { |
1565 |
< |
if (!(o instanceof Map.Entry)) |
1566 |
< |
return false; |
1567 |
< |
Map.Entry<?,?> e = (Map.Entry<?,?>)o; |
1568 |
< |
return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue()); |
1564 |
> |
|
1565 |
> |
public final boolean remove(Object o) { |
1566 |
> |
Object k, v; Map.Entry<?,?> e; |
1567 |
> |
return ((o instanceof Map.Entry) && |
1568 |
> |
(k = (e = (Map.Entry<?,?>)o).getKey()) != null && |
1569 |
> |
(v = e.getValue()) != null && |
1570 |
> |
map.remove(k, v)); |
1571 |
|
} |
1572 |
|
} |
1573 |
|
|
1574 |
|
/* ---------------- Serialization Support -------------- */ |
1575 |
|
|
1576 |
|
/** |
1577 |
< |
* Helper class used in previous version, declared for the sake of |
1578 |
< |
* serialization compatibility |
1577 |
> |
* Stripped-down version of helper class used in previous version, |
1578 |
> |
* declared for the sake of serialization compatibility |
1579 |
|
*/ |
1580 |
< |
static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock |
1514 |
< |
implements Serializable { |
1580 |
> |
static class Segment<K,V> implements Serializable { |
1581 |
|
private static final long serialVersionUID = 2249069246763182397L; |
1582 |
|
final float loadFactor; |
1583 |
|
Segment(float lf) { this.loadFactor = lf; } |
1599 |
|
segments = (Segment<K,V>[]) |
1600 |
|
new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; |
1601 |
|
for (int i = 0; i < segments.length; ++i) |
1602 |
< |
segments[i] = new Segment<K,V>(loadFactor); |
1602 |
> |
segments[i] = new Segment<K,V>(LOAD_FACTOR); |
1603 |
|
} |
1604 |
|
s.defaultWriteObject(); |
1605 |
< |
new HashIterator().writeEntries(s); |
1605 |
> |
InternalIterator it = new InternalIterator(table); |
1606 |
> |
while (it.next != null) { |
1607 |
> |
s.writeObject(it.nextKey); |
1608 |
> |
s.writeObject(it.nextVal); |
1609 |
> |
it.advance(); |
1610 |
> |
} |
1611 |
|
s.writeObject(null); |
1612 |
|
s.writeObject(null); |
1613 |
|
segments = null; // throw away |
1621 |
|
private void readObject(java.io.ObjectInputStream s) |
1622 |
|
throws java.io.IOException, ClassNotFoundException { |
1623 |
|
s.defaultReadObject(); |
1553 |
– |
// find load factor in a segment, if one exists |
1554 |
– |
if (segments != null && segments.length != 0) |
1555 |
– |
this.loadFactor = segments[0].loadFactor; |
1556 |
– |
else |
1557 |
– |
this.loadFactor = DEFAULT_LOAD_FACTOR; |
1558 |
– |
this.initCap = DEFAULT_CAPACITY; |
1559 |
– |
LongAdder ct = new LongAdder(); // force final field write |
1560 |
– |
UNSAFE.putObjectVolatile(this, counterOffset, ct); |
1624 |
|
this.segments = null; // unneeded |
1625 |
< |
|
1626 |
< |
// Read the keys and values, and put the mappings in the table |
1625 |
> |
// initalize transient final field |
1626 |
> |
UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder()); |
1627 |
> |
this.targetCapacity = DEFAULT_CAPACITY; |
1628 |
> |
|
1629 |
> |
// Create all nodes, then place in table once size is known |
1630 |
> |
long size = 0L; |
1631 |
> |
Node p = null; |
1632 |
|
for (;;) { |
1633 |
< |
K key = (K) s.readObject(); |
1634 |
< |
V value = (V) s.readObject(); |
1635 |
< |
if (key == null) |
1633 |
> |
K k = (K) s.readObject(); |
1634 |
> |
V v = (V) s.readObject(); |
1635 |
> |
if (k != null && v != null) { |
1636 |
> |
p = new Node(spread(k.hashCode()), k, v, p); |
1637 |
> |
++size; |
1638 |
> |
} |
1639 |
> |
else |
1640 |
|
break; |
1641 |
< |
put(key, value); |
1641 |
> |
} |
1642 |
> |
if (p != null) { |
1643 |
> |
boolean init = false; |
1644 |
> |
if (resizing == 0 && |
1645 |
> |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
1646 |
> |
try { |
1647 |
> |
if (table == null) { |
1648 |
> |
init = true; |
1649 |
> |
int n; |
1650 |
> |
if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) |
1651 |
> |
n = MAXIMUM_CAPACITY; |
1652 |
> |
else { |
1653 |
> |
int sz = (int)size; |
1654 |
> |
n = tableSizeFor(sz + (sz >>> 1) + 1); |
1655 |
> |
} |
1656 |
> |
threshold = n - (n >>> 2) - THRESHOLD_OFFSET; |
1657 |
> |
Node[] tab = new Node[n]; |
1658 |
> |
int mask = n - 1; |
1659 |
> |
while (p != null) { |
1660 |
> |
int j = p.hash & mask; |
1661 |
> |
Node next = p.next; |
1662 |
> |
p.next = tabAt(tab, j); |
1663 |
> |
setTabAt(tab, j, p); |
1664 |
> |
p = next; |
1665 |
> |
} |
1666 |
> |
table = tab; |
1667 |
> |
counter.add(size); |
1668 |
> |
} |
1669 |
> |
} finally { |
1670 |
> |
resizing = 0; |
1671 |
> |
} |
1672 |
> |
} |
1673 |
> |
if (!init) { // Can only happen if unsafely published. |
1674 |
> |
while (p != null) { |
1675 |
> |
internalPut(p.key, p.val, true); |
1676 |
> |
p = p.next; |
1677 |
> |
} |
1678 |
> |
} |
1679 |
|
} |
1680 |
|
} |
1681 |
|
|