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package jsr166e; |
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import jsr166e.LongAdder; |
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import java.util.Arrays; |
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import java.util.Map; |
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import java.util.Set; |
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import java.util.Collection; |
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import java.util.ConcurrentModificationException; |
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import java.util.NoSuchElementException; |
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import java.util.concurrent.ConcurrentMap; |
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import java.util.concurrent.locks.LockSupport; |
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import java.io.Serializable; |
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/** |
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* <p> The table is dynamically expanded when there are too many |
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* collisions (i.e., keys that have distinct hash codes but fall into |
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* the same slot modulo the table size), with the expected average |
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* effect of maintaining roughly two bins per mapping. There may be |
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* much variance around this average as mappings are added and |
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* removed, but overall, this maintains a commonly accepted time/space |
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* tradeoff for hash tables. However, resizing this or any other kind |
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* of hash table may be a relatively slow operation. When possible, it |
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* is a good idea to provide a size estimate as an optional {@code |
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* effect of maintaining roughly two bins per mapping (corresponding |
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* to a 0.75 load factor threshold for resizing). There may be much |
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* variance around this average as mappings are added and removed, but |
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* overall, this maintains a commonly accepted time/space tradeoff for |
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* hash tables. However, resizing this or any other kind of hash |
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* table may be a relatively slow operation. When possible, it is a |
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* good idea to provide a size estimate as an optional {@code |
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* initialCapacity} constructor argument. An additional optional |
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* {@code loadFactor} constructor argument provides a further means of |
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* customizing initial table capacity by specifying the table density |
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* The primary design goal of this hash table is to maintain |
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* concurrent readability (typically method get(), but also |
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* iterators and related methods) while minimizing update |
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* contention. |
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* contention. Secondary goals are to keep space consumption about |
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* the same or better than java.util.HashMap, and to support high |
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* initial insertion rates on an empty table by many threads. |
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* |
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* Each key-value mapping is held in a Node. Because Node fields |
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* can contain special values, they are defined using plain Object |
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* we use intrinsics (sun.misc.Unsafe) operations. The lists of |
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* nodes within bins are always accurately traversable under |
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* volatile reads, so long as lookups check hash code and |
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* non-nullness of value before checking key equality. (All valid |
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* hash codes are nonnegative. Negative values are reserved for |
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* special forwarding nodes; see below.) |
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* non-nullness of value before checking key equality. |
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* |
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* We use the top two bits of Node hash fields for control |
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* purposes -- they are available anyway because of addressing |
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* constraints. As explained further below, these top bits are |
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* usd as follows: |
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* 00 - Normal |
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* 01 - Locked |
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* 11 - Locked and may have a thread waiting for lock |
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* 10 - Node is a forwarding node |
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* |
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* The lower 30 bits of each Node's hash field contain a |
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* transformation (for better randomization -- method "spread") of |
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* the key's hash code, except for forwarding nodes, for which the |
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* lower bits are zero (and so always have hash field == "MOVED"). |
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* |
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* Insertion (via put or putIfAbsent) of the first node in an |
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* empty bin is performed by just CASing it to the bin. This is |
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* on average by far the most common case for put operations. |
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* Other update operations (insert, delete, and replace) require |
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* locks. We do not want to waste the space required to associate |
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* a distinct lock object with each bin, so instead use the first |
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* node of a bin list itself as a lock, using plain "synchronized" |
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* locks. These save space and we can live with block-structured |
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* lock/unlock operations. Using the first node of a list as a |
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* lock does not by itself suffice though: When a node is locked, |
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* any update must first validate that it is still the first node, |
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* and retry if not. Because new nodes are always appended to |
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* lists, once a node is first in a bin, it remains first until |
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* deleted or the bin becomes invalidated. However, operations |
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* that only conditionally update can and sometimes do inspect |
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* nodes until the point of update. This is a converse of sorts to |
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* the lazy locking technique described by Herlihy & Shavit. |
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* by far the most common case for put operations. Other update |
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* operations (insert, delete, and replace) require locks. We do |
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* not want to waste the space required to associate a distinct |
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* lock object with each bin, so instead use the first node of a |
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* bin list itself as a lock. Blocking support for these locks |
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* relies on the builtin "synchronized" monitors. However, we |
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* also need a tryLock construction, so we overlay these by using |
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* bits of the Node hash field for lock control (see above), and |
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* so normally use builtin monitors only for blocking and |
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* signalling using wait/notifyAll constructions. See |
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* Node.tryAwaitLock. |
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* |
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* Using the first node of a list as a lock does not by itself |
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* suffice though: When a node is locked, any update must first |
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* validate that it is still the first node after locking it, and |
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* retry if not. Because new nodes are always appended to lists, |
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* once a node is first in a bin, it remains first until deleted |
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* or the bin becomes invalidated. However, operations that only |
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* conditionally update may inspect nodes until the point of |
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* update. This is a converse of sorts to the lazy locking |
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* technique described by Herlihy & Shavit. |
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* |
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* The main disadvantage of this approach is that most update |
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* The main disadvantage of per-bin locks is that other update |
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* operations on other nodes in a bin list protected by the same |
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* lock can stall, for example when user equals() or mapping |
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* functions take a long time. However, statistically, this is |
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* that these assumptions hold unless users define exactly the |
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* same value for too many hashCodes. |
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* |
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* The table is resized when occupancy exceeds a threshold. Only |
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* a single thread performs the resize (using field "resizing", to |
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* arrange exclusion), but the table otherwise remains usable for |
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* reads and updates. Resizing proceeds by transferring bins, one |
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* by one, from the table to the next table. Upon transfer, the |
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* old table bin contains only a special forwarding node (with |
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* negative hash field) that contains the next table as its |
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* key. On encountering a forwarding node, access and update |
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* operations restart, using the new table. To ensure concurrent |
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* readability of traversals, transfers must proceed from the last |
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* bin (table.length - 1) up towards the first. Upon seeing a |
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* forwarding node, traversals (see class InternalIterator) |
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* arrange to move to the new table for the rest of the traversal |
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* without revisiting nodes. This constrains bin transfers to a |
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* particular order, and so can block indefinitely waiting for the |
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* next lock, and other threads cannot help with the transfer. |
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* However, expected stalls are infrequent enough to not warrant |
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* the additional overhead of access and iteration schemes that |
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* could admit out-of-order or concurrent bin transfers. |
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* The table is resized when occupancy exceeds an occupancy |
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* threshold (nominally, 0.75, but see below). Only a single |
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* thread performs the resize (using field "sizeCtl", to arrange |
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* exclusion), but the table otherwise remains usable for reads |
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* and updates. Resizing proceeds by transferring bins, one by |
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* one, from the table to the next table. Because we are using |
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* power-of-two expansion, the elements from each bin must either |
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* stay at same index, or move with a power of two offset. We |
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* eliminate unnecessary node creation by catching cases where old |
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* nodes can be reused because their next fields won't change. On |
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* average, only about one-sixth of them need cloning when a table |
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* doubles. The nodes they replace will be garbage collectable as |
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* soon as they are no longer referenced by any reader thread that |
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* may be in the midst of concurrently traversing table. Upon |
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* transfer, the old table bin contains only a special forwarding |
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* node (with hash field "MOVED") that contains the next table as |
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* its key. On encountering a forwarding node, access and update |
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* operations restart, using the new table. |
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* |
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* Each bin transfer requires its bin lock. However, unlike other |
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* cases, a transfer can skip a bin if it fails to acquire its |
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* lock, and revisit it later. Method rebuild maintains a buffer |
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* of TRANSFER_BUFFER_SIZE bins that have been skipped because of |
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* failure to acquire a lock, and blocks only if none are |
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* available (i.e., only very rarely). The transfer operation |
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* must also ensure that all accessible bins in both the old and |
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* new table are usable by any traversal. When there are no lock |
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* acquisition failures, this is arranged simply by proceeding |
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* from the last bin (table.length - 1) up towards the first. |
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* Upon seeing a forwarding node, traversals (see class |
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* InternalIterator) arrange to move to the new table without |
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* revisiting nodes. However, when any node is skipped during a |
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* transfer, all earlier table bins may have become visible, so |
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* are initialized with a reverse-forwarding node back to the old |
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* table until the new ones are established. (This sometimes |
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* requires transiently locking a forwarding node, which is |
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* possible under the above encoding.) These more expensive |
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* mechanics trigger only when necessary. |
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* |
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* This traversal scheme also applies to partial traversals of |
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* The traversal scheme also applies to partial traversals of |
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* ranges of bins (via an alternate InternalIterator constructor) |
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* to support partitioned aggregate operations (that are not |
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* otherwise implemented yet). Also, read-only operations give up |
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* Lazy table initialization minimizes footprint until first use, |
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* and also avoids resizings when the first operation is from a |
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* putAll, constructor with map argument, or deserialization. |
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* These cases attempt to override the targetCapacity used in |
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* growTable. These harmlessly fail to take effect in cases of |
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* races with other ongoing resizings. Uses of the threshold and |
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* targetCapacity during attempted initializations or resizings |
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* are racy but fall back on checks to preserve correctness. |
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* These cases attempt to override the initial capacity settings, |
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* but harmlessly fail to take effect in cases of races. |
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* |
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* The element count is maintained using a LongAdder, which avoids |
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* contention on updates but can encounter cache thrashing if read |
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* is around 13%, meaning that only about 1 in 8 puts check |
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* threshold (and after resizing, many fewer do so). But this |
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* approximation has high variance for small table sizes, so we |
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* check on any collision for sizes <= 64. Further, to increase |
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* the probability that a resize occurs soon enough, we offset the |
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* threshold (see THRESHOLD_OFFSET) by the expected number of puts |
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* between checks. |
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* check on any collision for sizes <= 64. |
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* |
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* Maintaining API and serialization compatibility with previous |
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* versions of this class introduces several oddities. Mainly: We |
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* leave untouched but unused constructor arguments refering to |
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* concurrencyLevel. We also declare an unused "Segment" class |
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* that is instantiated in minimal form only when serializing. |
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* concurrencyLevel. We accept a loadFactor constructor argument, |
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* but apply it only to initial table capacity (which is the only |
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* time that we can guarantee to honor it.) We also declare an |
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* unused "Segment" class that is instantiated in minimal form |
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* only when serializing. |
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*/ |
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|
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/* ---------------- Constants -------------- */ |
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/** |
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* The largest possible table capacity. This value must be |
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* exactly 1<<30 to stay within Java array allocation and indexing |
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* bounds for power of two table sizes. |
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* bounds for power of two table sizes, and is further required |
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* because the top two bits of 32bit hash fields are used for |
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* control purposes. |
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*/ |
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private static final int MAXIMUM_CAPACITY = 1 << 30; |
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|
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private static final int DEFAULT_CAPACITY = 16; |
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|
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/** |
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* The largest possible (non-power of two) array size. |
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* Needed by toArray and related methods. |
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*/ |
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static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
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|
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/** |
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* The default concurrency level for this table. Unused but |
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* defined for compatibility with previous versions of this class. |
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*/ |
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private static final int DEFAULT_CONCURRENCY_LEVEL = 16; |
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|
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/** |
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* The load factor for this table. Overrides of this value in |
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* constructors affect only the initial table capacity. The |
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* actual floating point value isn't normally used, because it is |
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* simpler to rely on the expression {@code n - (n >>> 2)} for the |
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* associated resizing threshold. |
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* actual floating point value isn't normally used -- it is |
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* simpler to use expressions such as {@code n - (n >>> 2)} for |
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* the associated resizing threshold. |
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*/ |
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private static final float LOAD_FACTOR = 0.75f; |
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|
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/** |
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* The count value to offset thresholds to compensate for checking |
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* for the need to resize only when inserting into bins with two |
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* or more elements. See above for explanation. |
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* The buffer size for skipped bins during transfers. The |
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* value is arbitrary but should be large enough to avoid |
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* most locking stalls during resizes. |
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*/ |
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private static final int TRANSFER_BUFFER_SIZE = 32; |
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|
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/* |
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* Encodings for special uses of Node hash fields. See above for |
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* explanation. |
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*/ |
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private static final int THRESHOLD_OFFSET = 8; |
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static final int MOVED = 0x80000000; // hash field for fowarding nodes |
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static final int LOCKED = 0x40000000; // set/tested only as a bit |
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static final int WAITING = 0xc0000000; // both bits set/tested together |
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static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash |
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|
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/* ---------------- Fields -------------- */ |
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|
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/** |
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* The default concurrency level for this table. Unused except as |
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* a sizing hint, but defined for compatibility with previous |
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* versions of this class. |
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* The array of bins. Lazily initialized upon first insertion. |
345 |
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* Size is always a power of two. Accessed directly by iterators. |
346 |
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*/ |
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< |
private static final int DEFAULT_CONCURRENCY_LEVEL = 16; |
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transient volatile Node[] table; |
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|
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> |
/** |
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* The counter maintaining number of elements. |
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*/ |
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> |
private transient final LongAdder counter; |
353 |
> |
|
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> |
/** |
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> |
* Table initialization and resizing control. When negative, the |
356 |
> |
* table is being initialized or resized. Otherwise, when table is |
357 |
> |
* null, holds the initial table size to use upon creation, or 0 |
358 |
> |
* for default. After initialization, holds the next element count |
359 |
> |
* value upon which to resize the table. |
360 |
> |
*/ |
361 |
> |
private transient volatile int sizeCtl; |
362 |
> |
|
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> |
// views |
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> |
private transient KeySet<K,V> keySet; |
365 |
> |
private transient Values<K,V> values; |
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> |
private transient EntrySet<K,V> entrySet; |
367 |
> |
|
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> |
/** For serialization compatibility. Null unless serialized; see below */ |
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> |
private Segment<K,V>[] segments; |
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|
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/* ---------------- Nodes -------------- */ |
372 |
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|
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/** |
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* Key-value entry. Note that this is never exported out as a |
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* user-visible Map.Entry. Nodes with a negative hash field are |
376 |
< |
* special, and do not contain user keys or values. Otherwise, |
377 |
< |
* keys are never null, and null val fields indicate that a node |
378 |
< |
* is in the process of being deleted or created. For purposes of |
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< |
* read-only, access, a key may be read before a val, but can only |
380 |
< |
* be used after checking val. (For an update operation, when a |
381 |
< |
* lock is held on a node, order doesn't matter.) |
375 |
> |
* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry |
376 |
> |
* below). Nodes with a negative hash field are special, and do |
377 |
> |
* not contain user keys or values. Otherwise, keys are never |
378 |
> |
* null, and null val fields indicate that a node is in the |
379 |
> |
* process of being deleted or created. For purposes of read-only |
380 |
> |
* access, a key may be read before a val, but can only be used |
381 |
> |
* after checking val to be non-null. |
382 |
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*/ |
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|
static final class Node { |
384 |
< |
final int hash; |
384 |
> |
volatile int hash; |
385 |
|
final Object key; |
386 |
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volatile Object val; |
387 |
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volatile Node next; |
392 |
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this.val = val; |
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this.next = next; |
394 |
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} |
310 |
– |
} |
311 |
– |
|
312 |
– |
/** |
313 |
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* Sign bit of node hash value indicating to use table in node.key. |
314 |
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*/ |
315 |
– |
private static final int SIGN_BIT = 0x80000000; |
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|
396 |
< |
/* ---------------- Fields -------------- */ |
396 |
> |
/** CompareAndSet the hash field */ |
397 |
> |
final boolean casHash(int cmp, int val) { |
398 |
> |
return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val); |
399 |
> |
} |
400 |
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|
401 |
< |
/** |
402 |
< |
* The array of bins. Lazily initialized upon first insertion. |
403 |
< |
* Size is always a power of two. Accessed directly by iterators. |
322 |
< |
*/ |
323 |
< |
transient volatile Node[] table; |
401 |
> |
/** The number of spins before blocking for a lock */ |
402 |
> |
static final int MAX_SPINS = |
403 |
> |
Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1; |
404 |
|
|
405 |
< |
/** The counter maintaining number of elements. */ |
406 |
< |
private transient final LongAdder counter; |
407 |
< |
/** Nonzero when table is being initialized or resized. Updated via CAS. */ |
408 |
< |
private transient volatile int resizing; |
409 |
< |
/** The next element count value upon which to resize the table. */ |
410 |
< |
private transient int threshold; |
411 |
< |
/** The target capacity; volatile to cover initialization races. */ |
412 |
< |
private transient volatile int targetCapacity; |
405 |
> |
/** |
406 |
> |
* Spins a while if LOCKED bit set and this node is the first |
407 |
> |
* of its bin, and then sets WAITING bits on hash field and |
408 |
> |
* blocks (once) if they are still set. It is OK for this |
409 |
> |
* method to return even if lock is not available upon exit, |
410 |
> |
* which enables these simple single-wait mechanics. |
411 |
> |
* |
412 |
> |
* The corresponding signalling operation is performed within |
413 |
> |
* callers: Upon detecting that WAITING has been set when |
414 |
> |
* unlocking lock (via a failed CAS from non-waiting LOCKED |
415 |
> |
* state), unlockers acquire the sync lock and perform a |
416 |
> |
* notifyAll. |
417 |
> |
*/ |
418 |
> |
final void tryAwaitLock(Node[] tab, int i) { |
419 |
> |
if (tab != null && i >= 0 && i < tab.length) { // bounds check |
420 |
> |
int spins = MAX_SPINS, h; |
421 |
> |
while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) { |
422 |
> |
if (spins >= 0) { |
423 |
> |
if (--spins == MAX_SPINS >>> 1) |
424 |
> |
Thread.yield(); // heuristically yield mid-way |
425 |
> |
} |
426 |
> |
else if (casHash(h, h | WAITING)) { |
427 |
> |
synchronized(this) { |
428 |
> |
if (tabAt(tab, i) == this && |
429 |
> |
(hash & WAITING) == WAITING) { |
430 |
> |
try { |
431 |
> |
wait(); |
432 |
> |
} catch (InterruptedException ie) { |
433 |
> |
Thread.currentThread().interrupt(); |
434 |
> |
} |
435 |
> |
} |
436 |
> |
else |
437 |
> |
notifyAll(); // possibly won race vs signaller |
438 |
> |
} |
439 |
> |
break; |
440 |
> |
} |
441 |
> |
} |
442 |
> |
} |
443 |
> |
} |
444 |
|
|
445 |
< |
// views |
446 |
< |
private transient KeySet<K,V> keySet; |
447 |
< |
private transient Values<K,V> values; |
337 |
< |
private transient EntrySet<K,V> entrySet; |
445 |
> |
// Unsafe mechanics for casHash |
446 |
> |
private static final sun.misc.Unsafe UNSAFE; |
447 |
> |
private static final long hashOffset; |
448 |
|
|
449 |
< |
/** For serialization compatibility. Null unless serialized; see below */ |
450 |
< |
private Segment<K,V>[] segments; |
449 |
> |
static { |
450 |
> |
try { |
451 |
> |
UNSAFE = getUnsafe(); |
452 |
> |
Class<?> k = Node.class; |
453 |
> |
hashOffset = UNSAFE.objectFieldOffset |
454 |
> |
(k.getDeclaredField("hash")); |
455 |
> |
} catch (Exception e) { |
456 |
> |
throw new Error(e); |
457 |
> |
} |
458 |
> |
} |
459 |
> |
} |
460 |
|
|
461 |
|
/* ---------------- Table element access -------------- */ |
462 |
|
|
484 |
|
UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v); |
485 |
|
} |
486 |
|
|
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 |
– |
/** |
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 |
– |
|
487 |
|
/* ---------------- Internal access and update methods -------------- */ |
488 |
|
|
489 |
|
/** |
490 |
|
* Applies a supplemental hash function to a given hashCode, which |
491 |
|
* defends against poor quality hash functions. The result must |
492 |
< |
* be non-negative, and for reasonable performance must have good |
493 |
< |
* avalanche properties; i.e., that each bit of the argument |
494 |
< |
* affects each bit (except sign bit) of the result. |
492 |
> |
* be have the top 2 bits clear. For reasonable performance, this |
493 |
> |
* function must have good avalanche properties; i.e., that each |
494 |
> |
* bit of the argument affects each bit of the result. (Although |
495 |
> |
* we don't care about the unused top 2 bits.) |
496 |
|
*/ |
497 |
|
private static final int spread(int h) { |
498 |
|
// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/ |
500 |
|
h *= 0x85ebca6b; |
501 |
|
h ^= h >>> 13; |
502 |
|
h *= 0xc2b2ae35; |
503 |
< |
return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit |
503 |
> |
return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits |
504 |
|
} |
505 |
|
|
506 |
|
/** Implementation for get and containsKey */ |
507 |
|
private final Object internalGet(Object k) { |
508 |
|
int h = spread(k.hashCode()); |
509 |
|
retry: for (Node[] tab = table; tab != null;) { |
510 |
< |
Node e; Object ek, ev; int eh; // locals to read fields once |
510 |
> |
Node e; Object ek, ev; int eh; // locals to read fields once |
511 |
|
for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) { |
512 |
< |
if ((eh = e.hash) == h) { |
513 |
< |
if ((ev = e.val) != null && |
512 |
< |
((ek = e.key) == k || k.equals(ek))) |
513 |
< |
return ev; |
514 |
< |
} |
515 |
< |
else if (eh < 0) { // sign bit set |
516 |
< |
tab = (Node[])e.key; // bin was moved during resize |
512 |
> |
if ((eh = e.hash) == MOVED) { |
513 |
> |
tab = (Node[])e.key; // restart with new table |
514 |
|
continue retry; |
515 |
|
} |
516 |
+ |
if ((eh & HASH_BITS) == h && (ev = e.val) != null && |
517 |
+ |
((ek = e.key) == k || k.equals(ek))) |
518 |
+ |
return ev; |
519 |
|
} |
520 |
|
break; |
521 |
|
} |
527 |
|
int h = spread(k.hashCode()); |
528 |
|
Object oldVal = null; // previous value or null if none |
529 |
|
for (Node[] tab = table;;) { |
530 |
< |
Node e; int i; Object ek, ev; |
530 |
> |
int i; Node f; int fh; Object fk, fv; |
531 |
|
if (tab == null) |
532 |
< |
tab = growTable(); |
533 |
< |
else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
532 |
> |
tab = initTable(); |
533 |
> |
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
534 |
|
if (casTabAt(tab, i, null, new Node(h, k, v, null))) |
535 |
|
break; // no lock when adding to empty bin |
536 |
|
} |
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 |
< |
} |
537 |
> |
else if ((fh = f.hash) == MOVED) |
538 |
> |
tab = (Node[])f.key; |
539 |
> |
else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null && |
540 |
> |
((fk = f.key) == k || k.equals(fk))) { |
541 |
> |
oldVal = fv; // precheck 1st node for putIfAbsent |
542 |
> |
break; |
543 |
|
} |
544 |
< |
else { |
544 |
> |
else if ((fh & LOCKED) != 0) |
545 |
> |
f.tryAwaitLock(tab, i); |
546 |
> |
else if (f.casHash(fh, fh | LOCKED)) { |
547 |
|
boolean validated = false; |
548 |
|
boolean checkSize = false; |
549 |
< |
synchronized (e) { // lock the 1st node of bin list |
550 |
< |
if (tabAt(tab, i) == e) { |
549 |
> |
try { |
550 |
> |
if (tabAt(tab, i) == f) { |
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) { |
552 |
> |
for (Node e = f;;) { |
553 |
> |
Object ek, ev; |
554 |
> |
if ((e.hash & HASH_BITS) == h && |
555 |
> |
(ev = e.val) != null && |
556 |
> |
((ek = e.key) == k || k.equals(ek))) { |
557 |
|
oldVal = ev; |
558 |
|
if (replace) |
559 |
|
e.val = v; |
562 |
|
Node last = e; |
563 |
|
if ((e = e.next) == null) { |
564 |
|
last.next = new Node(h, k, v, null); |
565 |
< |
if (last != first || tab.length <= 64) |
565 |
> |
if (last != f || tab.length <= 64) |
566 |
|
checkSize = true; |
567 |
|
break; |
568 |
|
} |
569 |
|
} |
570 |
|
} |
571 |
+ |
} finally { // unlock and signal if needed |
572 |
+ |
if (!f.casHash(fh | LOCKED, fh)) { |
573 |
+ |
f.hash = fh; |
574 |
+ |
synchronized(f) { f.notifyAll(); }; |
575 |
+ |
} |
576 |
|
} |
577 |
|
if (validated) { |
578 |
+ |
int sc; |
579 |
|
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
580 |
< |
resizing == 0 && counter.sum() >= (long)threshold) |
580 |
> |
(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc) |
581 |
|
growTable(); |
582 |
|
break; |
583 |
|
} |
595 |
|
*/ |
596 |
|
private final Object internalReplace(Object k, Object v, Object cv) { |
597 |
|
int h = spread(k.hashCode()); |
598 |
+ |
Object oldVal = null; |
599 |
|
for (Node[] tab = table;;) { |
600 |
< |
Node e; int i; |
600 |
> |
Node f; int i, fh; |
601 |
|
if (tab == null || |
602 |
< |
(e = tabAt(tab, i = (tab.length - 1) & h)) == null) |
603 |
< |
return null; |
604 |
< |
else if (e.hash < 0) |
605 |
< |
tab = (Node[])e.key; |
606 |
< |
else { |
607 |
< |
Object oldVal = null; |
602 |
> |
(f = tabAt(tab, i = (tab.length - 1) & h)) == null) |
603 |
> |
break; |
604 |
> |
else if ((fh = f.hash) == MOVED) |
605 |
> |
tab = (Node[])f.key; |
606 |
> |
else if ((fh & HASH_BITS) != h && f.next == null) // precheck |
607 |
> |
break; // rules out possible existence |
608 |
> |
else if ((fh & LOCKED) != 0) |
609 |
> |
f.tryAwaitLock(tab, i); |
610 |
> |
else if (f.casHash(fh, fh | LOCKED)) { |
611 |
|
boolean validated = false; |
612 |
|
boolean deleted = false; |
613 |
< |
synchronized (e) { |
614 |
< |
if (tabAt(tab, i) == e) { |
613 |
> |
try { |
614 |
> |
if (tabAt(tab, i) == f) { |
615 |
|
validated = true; |
616 |
< |
Node pred = null; |
606 |
< |
do { |
616 |
> |
for (Node e = f, pred = null;;) { |
617 |
|
Object ek, ev; |
618 |
< |
if (e.hash == h && |
619 |
< |
((ek = e.key) == k || k.equals(ek)) && |
620 |
< |
((ev = e.val) != null)) { |
618 |
> |
if ((e.hash & HASH_BITS) == h && |
619 |
> |
((ev = e.val) != null) && |
620 |
> |
((ek = e.key) == k || k.equals(ek))) { |
621 |
|
if (cv == null || cv == ev || cv.equals(ev)) { |
622 |
|
oldVal = ev; |
623 |
|
if ((e.val = v) == null) { |
631 |
|
} |
632 |
|
break; |
633 |
|
} |
634 |
< |
} while ((e = (pred = e).next) != null); |
634 |
> |
pred = e; |
635 |
> |
if ((e = e.next) == null) |
636 |
> |
break; |
637 |
> |
} |
638 |
> |
} |
639 |
> |
} finally { |
640 |
> |
if (!f.casHash(fh | LOCKED, fh)) { |
641 |
> |
f.hash = fh; |
642 |
> |
synchronized(f) { f.notifyAll(); }; |
643 |
|
} |
644 |
|
} |
645 |
|
if (validated) { |
646 |
|
if (deleted) |
647 |
|
counter.decrement(); |
648 |
< |
return oldVal; |
648 |
> |
break; |
649 |
|
} |
650 |
|
} |
651 |
|
} |
652 |
+ |
return oldVal; |
653 |
|
} |
654 |
|
|
655 |
|
/** Implementation for computeIfAbsent and compute. Like put, but messier. */ |
656 |
+ |
// Todo: Somehow reinstate non-termination check |
657 |
|
@SuppressWarnings("unchecked") |
658 |
|
private final V internalCompute(K k, |
659 |
< |
MappingFunction<? super K, ? extends V> f, |
659 |
> |
MappingFunction<? super K, ? extends V> fn, |
660 |
|
boolean replace) { |
661 |
|
int h = spread(k.hashCode()); |
662 |
|
V val = null; |
663 |
|
boolean added = false; |
664 |
|
Node[] tab = table; |
665 |
|
outer:for (;;) { |
666 |
< |
Node e; int i; Object ek, ev; |
666 |
> |
Node f; int i, fh; Object fk, fv; |
667 |
|
if (tab == null) |
668 |
< |
tab = growTable(); |
669 |
< |
else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
670 |
< |
Node node = new Node(h, k, null, null); |
668 |
> |
tab = initTable(); |
669 |
> |
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { |
670 |
> |
Node node = new Node(fh = h | LOCKED, k, null, null); |
671 |
|
boolean validated = false; |
672 |
< |
synchronized (node) { // must lock while computing value |
673 |
< |
if (casTabAt(tab, i, null, node)) { |
674 |
< |
validated = true; |
675 |
< |
try { |
676 |
< |
val = f.map(k); |
677 |
< |
if (val != null) { |
678 |
< |
node.val = val; |
679 |
< |
added = true; |
680 |
< |
} |
681 |
< |
} finally { |
682 |
< |
if (!added) |
683 |
< |
setTabAt(tab, i, null); |
672 |
> |
if (casTabAt(tab, i, null, node)) { |
673 |
> |
validated = true; |
674 |
> |
try { |
675 |
> |
val = fn.map(k); |
676 |
> |
if (val != null) { |
677 |
> |
node.val = val; |
678 |
> |
added = true; |
679 |
> |
} |
680 |
> |
} finally { |
681 |
> |
if (!added) |
682 |
> |
setTabAt(tab, i, null); |
683 |
> |
if (!node.casHash(fh, h)) { |
684 |
> |
node.hash = h; |
685 |
> |
synchronized(node) { node.notifyAll(); }; |
686 |
|
} |
687 |
|
} |
688 |
|
} |
689 |
|
if (validated) |
690 |
|
break; |
691 |
|
} |
692 |
< |
else if (e.hash < 0) |
693 |
< |
tab = (Node[])e.key; |
694 |
< |
else if (!replace && e.hash == h && (ev = e.val) != null && |
695 |
< |
((ek = e.key) == k || k.equals(ek))) { |
696 |
< |
if (tabAt(tab, i) == e) { |
697 |
< |
val = (V)ev; |
692 |
> |
else if ((fh = f.hash) == MOVED) |
693 |
> |
tab = (Node[])f.key; |
694 |
> |
else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null && |
695 |
> |
((fk = f.key) == k || k.equals(fk))) { |
696 |
> |
if (tabAt(tab, i) == f) { |
697 |
> |
val = (V)fv; |
698 |
|
break; |
699 |
|
} |
700 |
|
} |
701 |
< |
else if (Thread.holdsLock(e)) |
702 |
< |
throw new IllegalStateException("Recursive map computation"); |
703 |
< |
else { |
701 |
> |
else if ((fh & LOCKED) != 0) |
702 |
> |
f.tryAwaitLock(tab, i); |
703 |
> |
else if (f.casHash(fh, fh | LOCKED)) { |
704 |
|
boolean validated = false; |
705 |
|
boolean checkSize = false; |
706 |
< |
synchronized (e) { |
707 |
< |
if (tabAt(tab, i) == e) { |
706 |
> |
try { |
707 |
> |
if (tabAt(tab, i) == f) { |
708 |
|
validated = true; |
709 |
< |
for (Node first = e;;) { |
710 |
< |
if (e.hash == h && |
711 |
< |
((ek = e.key) == k || k.equals(ek)) && |
712 |
< |
((ev = e.val) != null)) { |
713 |
< |
Object fv; |
714 |
< |
if (replace && (fv = f.map(k)) != null) |
715 |
< |
ev = e.val = fv; |
709 |
> |
for (Node e = f;;) { |
710 |
> |
Object ek, ev, v; |
711 |
> |
if ((e.hash & HASH_BITS) == h && |
712 |
> |
(ev = e.val) != null && |
713 |
> |
((ek = e.key) == k || k.equals(ek))) { |
714 |
> |
if (replace && (v = fn.map(k)) != null) |
715 |
> |
ev = e.val = v; |
716 |
|
val = (V)ev; |
717 |
|
break; |
718 |
|
} |
719 |
|
Node last = e; |
720 |
|
if ((e = e.next) == null) { |
721 |
< |
if ((val = f.map(k)) != null) { |
721 |
> |
if ((val = fn.map(k)) != null) { |
722 |
|
last.next = new Node(h, k, val, null); |
723 |
|
added = true; |
724 |
< |
if (last != first || tab.length <= 64) |
724 |
> |
if (last != f || tab.length <= 64) |
725 |
|
checkSize = true; |
726 |
|
} |
727 |
|
break; |
728 |
|
} |
729 |
|
} |
730 |
|
} |
731 |
+ |
} finally { |
732 |
+ |
if (!f.casHash(fh | LOCKED, fh)) { |
733 |
+ |
f.hash = fh; |
734 |
+ |
synchronized(f) { f.notifyAll(); }; |
735 |
+ |
} |
736 |
|
} |
737 |
|
if (validated) { |
738 |
+ |
int sc; |
739 |
|
if (checkSize && tab.length < MAXIMUM_CAPACITY && |
740 |
< |
resizing == 0 && counter.sum() >= (long)threshold) |
740 |
> |
(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc) |
741 |
|
growTable(); |
742 |
|
break; |
743 |
|
} |
756 |
|
int i = 0; |
757 |
|
Node[] tab = table; |
758 |
|
while (tab != null && i < tab.length) { |
759 |
< |
Node e = tabAt(tab, i); |
760 |
< |
if (e == null) |
759 |
> |
int fh; |
760 |
> |
Node f = tabAt(tab, i); |
761 |
> |
if (f == null) |
762 |
|
++i; |
763 |
< |
else if (e.hash < 0) |
764 |
< |
tab = (Node[])e.key; |
765 |
< |
else { |
763 |
> |
else if ((fh = f.hash) == MOVED) |
764 |
> |
tab = (Node[])f.key; |
765 |
> |
else if ((fh & LOCKED) != 0) |
766 |
> |
f.tryAwaitLock(tab, i); |
767 |
> |
else if (f.casHash(fh, fh | LOCKED)) { |
768 |
|
boolean validated = false; |
769 |
< |
synchronized (e) { |
770 |
< |
if (tabAt(tab, i) == e) { |
769 |
> |
try { |
770 |
> |
if (tabAt(tab, i) == f) { |
771 |
|
validated = true; |
772 |
< |
Node en; |
742 |
< |
do { |
743 |
< |
en = e.next; |
772 |
> |
for (Node e = f; e != null; e = e.next) { |
773 |
|
if (e.val != null) { // currently always true |
774 |
|
e.val = null; |
775 |
|
--delta; |
776 |
|
} |
777 |
< |
} while ((e = en) != null); |
777 |
> |
} |
778 |
|
setTabAt(tab, i, null); |
779 |
|
} |
780 |
+ |
} finally { |
781 |
+ |
if (!f.casHash(fh | LOCKED, fh)) { |
782 |
+ |
f.hash = fh; |
783 |
+ |
synchronized(f) { f.notifyAll(); }; |
784 |
+ |
} |
785 |
|
} |
786 |
|
if (validated) |
787 |
|
++i; |
790 |
|
counter.add(delta); |
791 |
|
} |
792 |
|
|
793 |
+ |
/* ----------------Table Initialization and Resizing -------------- */ |
794 |
+ |
|
795 |
+ |
/** |
796 |
+ |
* Returns a power of two table size for the given desired capacity. |
797 |
+ |
* See Hackers Delight, sec 3.2 |
798 |
+ |
*/ |
799 |
+ |
private static final int tableSizeFor(int c) { |
800 |
+ |
int n = c - 1; |
801 |
+ |
n |= n >>> 1; |
802 |
+ |
n |= n >>> 2; |
803 |
+ |
n |= n >>> 4; |
804 |
+ |
n |= n >>> 8; |
805 |
+ |
n |= n >>> 16; |
806 |
+ |
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; |
807 |
+ |
} |
808 |
+ |
|
809 |
+ |
/** |
810 |
+ |
* Initializes table, using the size recorded in sizeCtl. |
811 |
+ |
*/ |
812 |
+ |
private final Node[] initTable() { |
813 |
+ |
Node[] tab; int sc; |
814 |
+ |
while ((tab = table) == null) { |
815 |
+ |
if ((sc = sizeCtl) < 0) |
816 |
+ |
Thread.yield(); // lost initialization race; just spin |
817 |
+ |
else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
818 |
+ |
try { |
819 |
+ |
if ((tab = table) == null) { |
820 |
+ |
int n = (sc > 0) ? sc : DEFAULT_CAPACITY; |
821 |
+ |
tab = table = new Node[n]; |
822 |
+ |
sc = n - (n >>> 2) - 1; |
823 |
+ |
} |
824 |
+ |
} finally { |
825 |
+ |
sizeCtl = sc; |
826 |
+ |
} |
827 |
+ |
break; |
828 |
+ |
} |
829 |
+ |
} |
830 |
+ |
return tab; |
831 |
+ |
} |
832 |
+ |
|
833 |
+ |
/** |
834 |
+ |
* If not already resizing, creates next table and transfers bins. |
835 |
+ |
* Rechecks occupancy after a transfer to see if another resize is |
836 |
+ |
* already needed because resizings are lagging additions. |
837 |
+ |
*/ |
838 |
+ |
private final void growTable() { |
839 |
+ |
int sc = sizeCtl; |
840 |
+ |
if (sc >= 0 && UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
841 |
+ |
try { |
842 |
+ |
Node[] tab; int n; |
843 |
+ |
while ((tab = table) != null && |
844 |
+ |
(n = tab.length) > 0 && n < MAXIMUM_CAPACITY && |
845 |
+ |
counter.sum() >= (long)sc) { |
846 |
+ |
table = rebuild(tab); |
847 |
+ |
sc = (n << 1) - (n >>> 1) - 1; |
848 |
+ |
} |
849 |
+ |
} finally { |
850 |
+ |
sizeCtl = sc; |
851 |
+ |
} |
852 |
+ |
} |
853 |
+ |
} |
854 |
+ |
|
855 |
+ |
/* |
856 |
+ |
* Moves and/or copies the nodes in each bin to new table. See |
857 |
+ |
* above for explanation. |
858 |
+ |
* |
859 |
+ |
* @return the new table |
860 |
+ |
*/ |
861 |
+ |
private static final Node[] rebuild(Node[] tab) { |
862 |
+ |
int n = tab.length; |
863 |
+ |
Node[] nextTab = new Node[n << 1]; |
864 |
+ |
Node fwd = new Node(MOVED, nextTab, null, null); |
865 |
+ |
int[] buffer = null; // holds bins to revisit; null until needed |
866 |
+ |
Node rev = null; // reverse forwarder; null until needed |
867 |
+ |
int nbuffered = 0; // the number of bins in buffer list |
868 |
+ |
int bufferIndex = 0; // buffer index of current buffered bin |
869 |
+ |
int bin = n - 1; // current non-buffered bin or -1 if none |
870 |
+ |
|
871 |
+ |
for (int i = bin;;) { // start upwards sweep |
872 |
+ |
int fh; Node f; |
873 |
+ |
if ((f = tabAt(tab, i)) == null) { |
874 |
+ |
if (bin >= 0) { // no lock needed (or available) |
875 |
+ |
if (!casTabAt(tab, i, f, fwd)) |
876 |
+ |
continue; |
877 |
+ |
} |
878 |
+ |
else { // transiently use a locked forwarding node |
879 |
+ |
Node g = new Node(MOVED|LOCKED, nextTab, null, null); |
880 |
+ |
if (!casTabAt(tab, i, f, g)) |
881 |
+ |
continue; |
882 |
+ |
setTabAt(nextTab, i, null); |
883 |
+ |
setTabAt(nextTab, i + n, null); |
884 |
+ |
setTabAt(tab, i, fwd); |
885 |
+ |
if (!g.casHash(MOVED|LOCKED, MOVED)) { |
886 |
+ |
g.hash = MOVED; |
887 |
+ |
synchronized(g) { g.notifyAll(); } |
888 |
+ |
} |
889 |
+ |
} |
890 |
+ |
} |
891 |
+ |
else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) { |
892 |
+ |
boolean validated = false; |
893 |
+ |
try { // split to lo and hi lists; copying as needed |
894 |
+ |
if (tabAt(tab, i) == f) { |
895 |
+ |
validated = true; |
896 |
+ |
Node e = f, lastRun = f; |
897 |
+ |
Node lo = null, hi = null; |
898 |
+ |
int runBit = e.hash & n; |
899 |
+ |
for (Node p = e.next; p != null; p = p.next) { |
900 |
+ |
int b = p.hash & n; |
901 |
+ |
if (b != runBit) { |
902 |
+ |
runBit = b; |
903 |
+ |
lastRun = p; |
904 |
+ |
} |
905 |
+ |
} |
906 |
+ |
if (runBit == 0) |
907 |
+ |
lo = lastRun; |
908 |
+ |
else |
909 |
+ |
hi = lastRun; |
910 |
+ |
for (Node p = e; p != lastRun; p = p.next) { |
911 |
+ |
int ph = p.hash & HASH_BITS; |
912 |
+ |
Object pk = p.key, pv = p.val; |
913 |
+ |
if ((ph & n) == 0) |
914 |
+ |
lo = new Node(ph, pk, pv, lo); |
915 |
+ |
else |
916 |
+ |
hi = new Node(ph, pk, pv, hi); |
917 |
+ |
} |
918 |
+ |
setTabAt(nextTab, i, lo); |
919 |
+ |
setTabAt(nextTab, i + n, hi); |
920 |
+ |
setTabAt(tab, i, fwd); |
921 |
+ |
} |
922 |
+ |
} finally { |
923 |
+ |
if (!f.casHash(fh | LOCKED, fh)) { |
924 |
+ |
f.hash = fh; |
925 |
+ |
synchronized(f) { f.notifyAll(); }; |
926 |
+ |
} |
927 |
+ |
} |
928 |
+ |
if (!validated) |
929 |
+ |
continue; |
930 |
+ |
} |
931 |
+ |
else { |
932 |
+ |
if (buffer == null) // initialize buffer for revisits |
933 |
+ |
buffer = new int[TRANSFER_BUFFER_SIZE]; |
934 |
+ |
if (bin < 0 && bufferIndex > 0) { |
935 |
+ |
int j = buffer[--bufferIndex]; |
936 |
+ |
buffer[bufferIndex] = i; |
937 |
+ |
i = j; // swap with another bin |
938 |
+ |
continue; |
939 |
+ |
} |
940 |
+ |
if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) { |
941 |
+ |
f.tryAwaitLock(tab, i); |
942 |
+ |
continue; // no other options -- block |
943 |
+ |
} |
944 |
+ |
if (rev == null) // initialize reverse-forwarder |
945 |
+ |
rev = new Node(MOVED, tab, null, null); |
946 |
+ |
if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0) |
947 |
+ |
continue; // recheck before adding to list |
948 |
+ |
buffer[nbuffered++] = i; |
949 |
+ |
setTabAt(nextTab, i, rev); // install place-holders |
950 |
+ |
setTabAt(nextTab, i + n, rev); |
951 |
+ |
} |
952 |
+ |
|
953 |
+ |
if (bin > 0) |
954 |
+ |
i = --bin; |
955 |
+ |
else if (buffer != null && nbuffered > 0) { |
956 |
+ |
bin = -1; |
957 |
+ |
i = buffer[bufferIndex = --nbuffered]; |
958 |
+ |
} |
959 |
+ |
else |
960 |
+ |
return nextTab; |
961 |
+ |
} |
962 |
+ |
} |
963 |
+ |
|
964 |
|
/* ----------------Table Traversal -------------- */ |
965 |
|
|
966 |
|
/** |
976 |
|
* valid. |
977 |
|
* |
978 |
|
* Internal traversals directly access these fields, as in: |
979 |
< |
* {@code while (it.next != null) { process(nextKey); it.advance(); }} |
979 |
> |
* {@code while (it.next != null) { process(it.nextKey); it.advance(); }} |
980 |
|
* |
981 |
|
* Exported iterators (subclasses of ViewIterator) extract key, |
982 |
|
* value, or key-value pairs as return values of Iterator.next(), |
1035 |
|
final void advance() { |
1036 |
|
Node e = last = next; |
1037 |
|
outer: do { |
1038 |
< |
if (e != null) // pass used or skipped node |
1038 |
> |
if (e != null) // advance past used/skipped node |
1039 |
|
e = e.next; |
1040 |
< |
while (e == null) { // get to next non-null bin |
1041 |
< |
Node[] t; int b, i, n; // checks must use locals |
1040 |
> |
while (e == null) { // get to next non-null bin |
1041 |
> |
Node[] t; int b, i, n; // checks must use locals |
1042 |
|
if ((b = baseIndex) >= baseLimit || (i = index) < 0 || |
1043 |
|
(t = tab) == null || i >= (n = t.length)) |
1044 |
|
break outer; |
1045 |
< |
else if ((e = tabAt(t, i)) != null && e.hash < 0) |
1046 |
< |
tab = (Node[])e.key; // restarts due to null val |
1047 |
< |
else // visit upper slots if present |
1045 |
> |
else if ((e = tabAt(t, i)) != null && e.hash == MOVED) |
1046 |
> |
tab = (Node[])e.key; // restarts due to null val |
1047 |
> |
else // visit upper slots if present |
1048 |
|
index = (i += baseSize) < n ? i : (baseIndex = b + 1); |
1049 |
|
} |
1050 |
|
nextKey = e.key; |
1051 |
< |
} while ((nextVal = e.val) == null); // skip deleted or special nodes |
1051 |
> |
} while ((nextVal = e.val) == null);// skip deleted or special nodes |
1052 |
|
next = e; |
1053 |
|
} |
1054 |
|
} |
1060 |
|
*/ |
1061 |
|
public ConcurrentHashMapV8() { |
1062 |
|
this.counter = new LongAdder(); |
858 |
– |
this.targetCapacity = DEFAULT_CAPACITY; |
1063 |
|
} |
1064 |
|
|
1065 |
|
/** |
1079 |
|
MAXIMUM_CAPACITY : |
1080 |
|
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); |
1081 |
|
this.counter = new LongAdder(); |
1082 |
< |
this.targetCapacity = cap; |
1082 |
> |
this.sizeCtl = cap; |
1083 |
|
} |
1084 |
|
|
1085 |
|
/** |
1089 |
|
*/ |
1090 |
|
public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) { |
1091 |
|
this.counter = new LongAdder(); |
1092 |
< |
this.targetCapacity = DEFAULT_CAPACITY; |
1092 |
> |
this.sizeCtl = DEFAULT_CAPACITY; |
1093 |
|
putAll(m); |
1094 |
|
} |
1095 |
|
|
1140 |
|
int cap = ((size >= (long)MAXIMUM_CAPACITY) ? |
1141 |
|
MAXIMUM_CAPACITY: tableSizeFor((int)size)); |
1142 |
|
this.counter = new LongAdder(); |
1143 |
< |
this.targetCapacity = cap; |
1143 |
> |
this.sizeCtl = cap; |
1144 |
|
} |
1145 |
|
|
1146 |
|
/** |
1160 |
|
(int)n); |
1161 |
|
} |
1162 |
|
|
1163 |
+ |
final long longSize() { // accurate version of size needed for views |
1164 |
+ |
long n = counter.sum(); |
1165 |
+ |
return (n < 0L) ? 0L : n; |
1166 |
+ |
} |
1167 |
+ |
|
1168 |
|
/** |
1169 |
|
* Returns the value to which the specified key is mapped, |
1170 |
|
* or {@code null} if this map contains no mapping for the key. |
1285 |
|
if (m == null) |
1286 |
|
throw new NullPointerException(); |
1287 |
|
/* |
1288 |
< |
* If uninitialized, try to adjust targetCapacity to |
1080 |
< |
* accommodate the given number of elements. |
1288 |
> |
* If uninitialized, try to preallocate big enough table |
1289 |
|
*/ |
1290 |
|
if (table == null) { |
1291 |
|
int size = m.size(); |
1292 |
< |
int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : |
1292 |
> |
int n = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : |
1293 |
|
tableSizeFor(size + (size >>> 1) + 1); |
1294 |
< |
if (cap > targetCapacity) |
1295 |
< |
targetCapacity = cap; |
1294 |
> |
int sc = sizeCtl; |
1295 |
> |
if (n < sc) |
1296 |
> |
n = sc; |
1297 |
> |
if (sc >= 0 && |
1298 |
> |
UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
1299 |
> |
try { |
1300 |
> |
if (table == null) { |
1301 |
> |
table = new Node[n]; |
1302 |
> |
sc = n - (n >>> 2) - 1; |
1303 |
> |
} |
1304 |
> |
} finally { |
1305 |
> |
sizeCtl = sc; |
1306 |
> |
} |
1307 |
> |
} |
1308 |
> |
} |
1309 |
> |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { |
1310 |
> |
Object ek = e.getKey(), ev = e.getValue(); |
1311 |
> |
if (ek == null || ev == null) |
1312 |
> |
throw new NullPointerException(); |
1313 |
> |
internalPut(ek, ev, true); |
1314 |
|
} |
1089 |
– |
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) |
1090 |
– |
put(e.getKey(), e.getValue()); |
1315 |
|
} |
1316 |
|
|
1317 |
|
/** |
1686 |
|
Object k = nextKey; |
1687 |
|
Object v = nextVal; |
1688 |
|
advance(); |
1689 |
< |
return new WriteThroughEntry<K,V>(map, (K)k, (V)v); |
1689 |
> |
return new WriteThroughEntry<K,V>((K)k, (V)v, map); |
1690 |
> |
} |
1691 |
> |
} |
1692 |
> |
|
1693 |
> |
static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V> |
1694 |
> |
implements Iterator<Map.Entry<K,V>> { |
1695 |
> |
SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); } |
1696 |
> |
|
1697 |
> |
@SuppressWarnings("unchecked") |
1698 |
> |
public final Map.Entry<K,V> next() { |
1699 |
> |
if (next == null) |
1700 |
> |
throw new NoSuchElementException(); |
1701 |
> |
Object k = nextKey; |
1702 |
> |
Object v = nextVal; |
1703 |
> |
advance(); |
1704 |
> |
return new SnapshotEntry<K,V>((K)k, (V)v); |
1705 |
|
} |
1706 |
|
} |
1707 |
|
|
1708 |
|
/** |
1709 |
< |
* Custom Entry class used by EntryIterator.next(), that relays |
1471 |
< |
* setValue changes to the underlying map. |
1709 |
> |
* Base of writeThrough and Snapshot entry classes |
1710 |
|
*/ |
1711 |
< |
static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> { |
1474 |
< |
final ConcurrentHashMapV8<K, V> map; |
1711 |
> |
static abstract class MapEntry<K,V> implements Map.Entry<K, V> { |
1712 |
|
final K key; // non-null |
1713 |
|
V val; // non-null |
1714 |
< |
WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) { |
1478 |
< |
this.map = map; this.key = key; this.val = val; |
1479 |
< |
} |
1480 |
< |
|
1714 |
> |
MapEntry(K key, V val) { this.key = key; this.val = val; } |
1715 |
|
public final K getKey() { return key; } |
1716 |
|
public final V getValue() { return val; } |
1717 |
|
public final int hashCode() { return key.hashCode() ^ val.hashCode(); } |
1726 |
|
(v == val || v.equals(val))); |
1727 |
|
} |
1728 |
|
|
1729 |
+ |
public abstract V setValue(V value); |
1730 |
+ |
} |
1731 |
+ |
|
1732 |
+ |
/** |
1733 |
+ |
* Entry used by EntryIterator.next(), that relays setValue |
1734 |
+ |
* changes to the underlying map. |
1735 |
+ |
*/ |
1736 |
+ |
static final class WriteThroughEntry<K,V> extends MapEntry<K,V> |
1737 |
+ |
implements Map.Entry<K, V> { |
1738 |
+ |
final ConcurrentHashMapV8<K, V> map; |
1739 |
+ |
WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) { |
1740 |
+ |
super(key, val); |
1741 |
+ |
this.map = map; |
1742 |
+ |
} |
1743 |
+ |
|
1744 |
|
/** |
1745 |
|
* Sets our entry's value and writes through to the map. The |
1746 |
|
* value to return is somewhat arbitrary here. Since a |
1759 |
|
} |
1760 |
|
} |
1761 |
|
|
1762 |
+ |
/** |
1763 |
+ |
* Internal version of entry, that doesn't write though changes |
1764 |
+ |
*/ |
1765 |
+ |
static final class SnapshotEntry<K,V> extends MapEntry<K,V> |
1766 |
+ |
implements Map.Entry<K, V> { |
1767 |
+ |
SnapshotEntry(K key, V val) { super(key, val); } |
1768 |
+ |
public final V setValue(V value) { // only locally update |
1769 |
+ |
if (value == null) throw new NullPointerException(); |
1770 |
+ |
V v = val; |
1771 |
+ |
val = value; |
1772 |
+ |
return v; |
1773 |
+ |
} |
1774 |
+ |
} |
1775 |
+ |
|
1776 |
|
/* ----------------Views -------------- */ |
1777 |
|
|
1778 |
< |
/* |
1779 |
< |
* These currently just extend java.util.AbstractX classes, but |
1780 |
< |
* may need a new custom base to support partitioned traversal. |
1778 |
> |
/** |
1779 |
> |
* Base class for views. This is done mainly to allow adding |
1780 |
> |
* customized parallel traversals (not yet implemented.) |
1781 |
|
*/ |
1782 |
< |
|
1520 |
< |
static final class KeySet<K,V> extends AbstractSet<K> { |
1782 |
> |
static abstract class MapView<K, V> { |
1783 |
|
final ConcurrentHashMapV8<K, V> map; |
1784 |
< |
KeySet(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1523 |
< |
|
1784 |
> |
MapView(ConcurrentHashMapV8<K, V> map) { this.map = map; } |
1785 |
|
public final int size() { return map.size(); } |
1786 |
|
public final boolean isEmpty() { return map.isEmpty(); } |
1787 |
|
public final void clear() { map.clear(); } |
1788 |
+ |
|
1789 |
+ |
// implementations below rely on concrete classes supplying these |
1790 |
+ |
abstract Iterator<?> iter(); |
1791 |
+ |
abstract public boolean contains(Object o); |
1792 |
+ |
abstract public boolean remove(Object o); |
1793 |
+ |
|
1794 |
+ |
private static final String oomeMsg = "Required array size too large"; |
1795 |
+ |
|
1796 |
+ |
public final Object[] toArray() { |
1797 |
+ |
long sz = map.longSize(); |
1798 |
+ |
if (sz > (long)(MAX_ARRAY_SIZE)) |
1799 |
+ |
throw new OutOfMemoryError(oomeMsg); |
1800 |
+ |
int n = (int)sz; |
1801 |
+ |
Object[] r = new Object[n]; |
1802 |
+ |
int i = 0; |
1803 |
+ |
Iterator<?> it = iter(); |
1804 |
+ |
while (it.hasNext()) { |
1805 |
+ |
if (i == n) { |
1806 |
+ |
if (n >= MAX_ARRAY_SIZE) |
1807 |
+ |
throw new OutOfMemoryError(oomeMsg); |
1808 |
+ |
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) |
1809 |
+ |
n = MAX_ARRAY_SIZE; |
1810 |
+ |
else |
1811 |
+ |
n += (n >>> 1) + 1; |
1812 |
+ |
r = Arrays.copyOf(r, n); |
1813 |
+ |
} |
1814 |
+ |
r[i++] = it.next(); |
1815 |
+ |
} |
1816 |
+ |
return (i == n) ? r : Arrays.copyOf(r, i); |
1817 |
+ |
} |
1818 |
+ |
|
1819 |
+ |
@SuppressWarnings("unchecked") |
1820 |
+ |
public final <T> T[] toArray(T[] a) { |
1821 |
+ |
long sz = map.longSize(); |
1822 |
+ |
if (sz > (long)(MAX_ARRAY_SIZE)) |
1823 |
+ |
throw new OutOfMemoryError(oomeMsg); |
1824 |
+ |
int m = (int)sz; |
1825 |
+ |
T[] r = (a.length >= m) ? a : |
1826 |
+ |
(T[])java.lang.reflect.Array |
1827 |
+ |
.newInstance(a.getClass().getComponentType(), m); |
1828 |
+ |
int n = r.length; |
1829 |
+ |
int i = 0; |
1830 |
+ |
Iterator<?> it = iter(); |
1831 |
+ |
while (it.hasNext()) { |
1832 |
+ |
if (i == n) { |
1833 |
+ |
if (n >= MAX_ARRAY_SIZE) |
1834 |
+ |
throw new OutOfMemoryError(oomeMsg); |
1835 |
+ |
if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) |
1836 |
+ |
n = MAX_ARRAY_SIZE; |
1837 |
+ |
else |
1838 |
+ |
n += (n >>> 1) + 1; |
1839 |
+ |
r = Arrays.copyOf(r, n); |
1840 |
+ |
} |
1841 |
+ |
r[i++] = (T)it.next(); |
1842 |
+ |
} |
1843 |
+ |
if (a == r && i < n) { |
1844 |
+ |
r[i] = null; // null-terminate |
1845 |
+ |
return r; |
1846 |
+ |
} |
1847 |
+ |
return (i == n) ? r : Arrays.copyOf(r, i); |
1848 |
+ |
} |
1849 |
+ |
|
1850 |
+ |
public final int hashCode() { |
1851 |
+ |
int h = 0; |
1852 |
+ |
for (Iterator<?> it = iter(); it.hasNext();) |
1853 |
+ |
h += it.next().hashCode(); |
1854 |
+ |
return h; |
1855 |
+ |
} |
1856 |
+ |
|
1857 |
+ |
public final String toString() { |
1858 |
+ |
StringBuilder sb = new StringBuilder(); |
1859 |
+ |
sb.append('['); |
1860 |
+ |
Iterator<?> it = iter(); |
1861 |
+ |
if (it.hasNext()) { |
1862 |
+ |
for (;;) { |
1863 |
+ |
Object e = it.next(); |
1864 |
+ |
sb.append(e == this ? "(this Collection)" : e); |
1865 |
+ |
if (!it.hasNext()) |
1866 |
+ |
break; |
1867 |
+ |
sb.append(',').append(' '); |
1868 |
+ |
} |
1869 |
+ |
} |
1870 |
+ |
return sb.append(']').toString(); |
1871 |
+ |
} |
1872 |
+ |
|
1873 |
+ |
public final boolean containsAll(Collection<?> c) { |
1874 |
+ |
if (c != this) { |
1875 |
+ |
for (Iterator<?> it = c.iterator(); it.hasNext();) { |
1876 |
+ |
Object e = it.next(); |
1877 |
+ |
if (e == null || !contains(e)) |
1878 |
+ |
return false; |
1879 |
+ |
} |
1880 |
+ |
} |
1881 |
+ |
return true; |
1882 |
+ |
} |
1883 |
+ |
|
1884 |
+ |
public final boolean removeAll(Collection c) { |
1885 |
+ |
boolean modified = false; |
1886 |
+ |
for (Iterator<?> it = iter(); it.hasNext();) { |
1887 |
+ |
if (c.contains(it.next())) { |
1888 |
+ |
it.remove(); |
1889 |
+ |
modified = true; |
1890 |
+ |
} |
1891 |
+ |
} |
1892 |
+ |
return modified; |
1893 |
+ |
} |
1894 |
+ |
|
1895 |
+ |
public final boolean retainAll(Collection<?> c) { |
1896 |
+ |
boolean modified = false; |
1897 |
+ |
for (Iterator<?> it = iter(); it.hasNext();) { |
1898 |
+ |
if (!c.contains(it.next())) { |
1899 |
+ |
it.remove(); |
1900 |
+ |
modified = true; |
1901 |
+ |
} |
1902 |
+ |
} |
1903 |
+ |
return modified; |
1904 |
+ |
} |
1905 |
+ |
|
1906 |
+ |
} |
1907 |
+ |
|
1908 |
+ |
static final class KeySet<K,V> extends MapView<K,V> implements Set<K> { |
1909 |
+ |
KeySet(ConcurrentHashMapV8<K, V> map) { super(map); } |
1910 |
|
public final boolean contains(Object o) { return map.containsKey(o); } |
1911 |
|
public final boolean remove(Object o) { return map.remove(o) != null; } |
1912 |
+ |
|
1913 |
|
public final Iterator<K> iterator() { |
1914 |
|
return new KeyIterator<K,V>(map); |
1915 |
|
} |
1916 |
+ |
final Iterator<?> iter() { |
1917 |
+ |
return new KeyIterator<K,V>(map); |
1918 |
+ |
} |
1919 |
+ |
public final boolean add(K e) { |
1920 |
+ |
throw new UnsupportedOperationException(); |
1921 |
+ |
} |
1922 |
+ |
public final boolean addAll(Collection<? extends K> c) { |
1923 |
+ |
throw new UnsupportedOperationException(); |
1924 |
+ |
} |
1925 |
+ |
public boolean equals(Object o) { |
1926 |
+ |
Set<?> c; |
1927 |
+ |
return ((o instanceof Set) && |
1928 |
+ |
((c = (Set<?>)o) == this || |
1929 |
+ |
(containsAll(c) && c.containsAll(this)))); |
1930 |
+ |
} |
1931 |
|
} |
1932 |
|
|
1933 |
< |
static final class Values<K,V> extends AbstractCollection<V> { |
1934 |
< |
final ConcurrentHashMapV8<K, V> map; |
1935 |
< |
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(); } |
1933 |
> |
static final class Values<K,V> extends MapView<K,V> |
1934 |
> |
implements Collection<V> { |
1935 |
> |
Values(ConcurrentHashMapV8<K, V> map) { super(map); } |
1936 |
|
public final boolean contains(Object o) { return map.containsValue(o); } |
1937 |
+ |
|
1938 |
+ |
public final boolean remove(Object o) { |
1939 |
+ |
if (o != null) { |
1940 |
+ |
Iterator<V> it = new ValueIterator<K,V>(map); |
1941 |
+ |
while (it.hasNext()) { |
1942 |
+ |
if (o.equals(it.next())) { |
1943 |
+ |
it.remove(); |
1944 |
+ |
return true; |
1945 |
+ |
} |
1946 |
+ |
} |
1947 |
+ |
} |
1948 |
+ |
return false; |
1949 |
+ |
} |
1950 |
|
public final Iterator<V> iterator() { |
1951 |
|
return new ValueIterator<K,V>(map); |
1952 |
|
} |
1953 |
+ |
final Iterator<?> iter() { |
1954 |
+ |
return new ValueIterator<K,V>(map); |
1955 |
+ |
} |
1956 |
+ |
public final boolean add(V e) { |
1957 |
+ |
throw new UnsupportedOperationException(); |
1958 |
+ |
} |
1959 |
+ |
public final boolean addAll(Collection<? extends V> c) { |
1960 |
+ |
throw new UnsupportedOperationException(); |
1961 |
+ |
} |
1962 |
|
} |
1963 |
|
|
1964 |
< |
static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> { |
1965 |
< |
final ConcurrentHashMapV8<K, V> map; |
1966 |
< |
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 |
< |
} |
1964 |
> |
static final class EntrySet<K,V> extends MapView<K,V> |
1965 |
> |
implements Set<Map.Entry<K,V>> { |
1966 |
> |
EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); } |
1967 |
|
|
1968 |
|
public final boolean contains(Object o) { |
1969 |
|
Object k, v, r; Map.Entry<?,?> e; |
1981 |
|
(v = e.getValue()) != null && |
1982 |
|
map.remove(k, v)); |
1983 |
|
} |
1984 |
+ |
|
1985 |
+ |
public final Iterator<Map.Entry<K,V>> iterator() { |
1986 |
+ |
return new EntryIterator<K,V>(map); |
1987 |
+ |
} |
1988 |
+ |
final Iterator<?> iter() { |
1989 |
+ |
return new SnapshotEntryIterator<K,V>(map); |
1990 |
+ |
} |
1991 |
+ |
public final boolean add(Entry<K,V> e) { |
1992 |
+ |
throw new UnsupportedOperationException(); |
1993 |
+ |
} |
1994 |
+ |
public final boolean addAll(Collection<? extends Entry<K,V>> c) { |
1995 |
+ |
throw new UnsupportedOperationException(); |
1996 |
+ |
} |
1997 |
+ |
public boolean equals(Object o) { |
1998 |
+ |
Set<?> c; |
1999 |
+ |
return ((o instanceof Set) && |
2000 |
+ |
((c = (Set<?>)o) == this || |
2001 |
+ |
(containsAll(c) && c.containsAll(this)))); |
2002 |
+ |
} |
2003 |
|
} |
2004 |
|
|
2005 |
|
/* ---------------- Serialization Support -------------- */ |
2055 |
|
this.segments = null; // unneeded |
2056 |
|
// initialize transient final field |
2057 |
|
UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder()); |
1629 |
– |
this.targetCapacity = DEFAULT_CAPACITY; |
2058 |
|
|
2059 |
|
// Create all nodes, then place in table once size is known |
2060 |
|
long size = 0L; |
2071 |
|
} |
2072 |
|
if (p != null) { |
2073 |
|
boolean init = false; |
2074 |
< |
if (resizing == 0 && |
2075 |
< |
UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) { |
2074 |
> |
int n; |
2075 |
> |
if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) |
2076 |
> |
n = MAXIMUM_CAPACITY; |
2077 |
> |
else { |
2078 |
> |
int sz = (int)size; |
2079 |
> |
n = tableSizeFor(sz + (sz >>> 1) + 1); |
2080 |
> |
} |
2081 |
> |
int sc = sizeCtl; |
2082 |
> |
if (n > sc && |
2083 |
> |
UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) { |
2084 |
|
try { |
2085 |
|
if (table == null) { |
2086 |
|
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; |
2087 |
|
Node[] tab = new Node[n]; |
2088 |
|
int mask = n - 1; |
2089 |
|
while (p != null) { |
2095 |
|
} |
2096 |
|
table = tab; |
2097 |
|
counter.add(size); |
2098 |
+ |
sc = n - (n >>> 2) - 1; |
2099 |
|
} |
2100 |
|
} finally { |
2101 |
< |
resizing = 0; |
2101 |
> |
sizeCtl = sc; |
2102 |
|
} |
2103 |
|
} |
2104 |
|
if (!init) { // Can only happen if unsafely published. |
2113 |
|
// Unsafe mechanics |
2114 |
|
private static final sun.misc.Unsafe UNSAFE; |
2115 |
|
private static final long counterOffset; |
2116 |
< |
private static final long resizingOffset; |
2116 |
> |
private static final long sizeCtlOffset; |
2117 |
|
private static final long ABASE; |
2118 |
|
private static final int ASHIFT; |
2119 |
|
|
2124 |
|
Class<?> k = ConcurrentHashMapV8.class; |
2125 |
|
counterOffset = UNSAFE.objectFieldOffset |
2126 |
|
(k.getDeclaredField("counter")); |
2127 |
< |
resizingOffset = UNSAFE.objectFieldOffset |
2128 |
< |
(k.getDeclaredField("resizing")); |
2127 |
> |
sizeCtlOffset = UNSAFE.objectFieldOffset |
2128 |
> |
(k.getDeclaredField("sizeCtl")); |
2129 |
|
Class<?> sc = Node[].class; |
2130 |
|
ABASE = UNSAFE.arrayBaseOffset(sc); |
2131 |
|
ss = UNSAFE.arrayIndexScale(sc); |