SegmentedHashMap (Java API Reference for Oracle® Coherence Community Edition)

java.lang.Object
- com.tangosol.util.Base
- - com.tangosol.util.SegmentedHashMap

All Implemented Interfaces:

Map

Direct Known Subclasses:

SegmentedConcurrentMap
```
public class SegmentedHashMap
extends Base
implements Map
```
An implementation of java.util.Map that is optimized for heavy concurrent use.
Retrieval and update operations to the map (e.g. get, put) are non-blocking and uncontended and will reflect some state of the map. Insert and remove operations to the map (e.g. put, remove) do require internal locking.
The entries in the map are internally segmented so as to permit a high level of concurrent "locked" operations without contention.
Retrievals and updates that run concurrently with bulk operations (e.g. putAll, clear may reflect insertion or removal of only some entries. Iterators on the Map may also reflect concurrent updates made since the Iterator was created. However, Iterators will not throw ConcurrentModificationException.

Since:

Coherence 3.5

Author:

rhl 2008.12.01

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`SegmentedHashMap.ContainsValueAction` Action support for containsValue().
`protected static class`	`SegmentedHashMap.Entry` A map entry (key-value pair).
`protected static interface`	`SegmentedHashMap.EntryAction` An EntryAction encapsulates a logical action to be executed in the context of a key (that may or may not exist in the map).
`protected static class`	`SegmentedHashMap.EntryActionAdapter` EntryActionAdapter is a convenience class that provides default implementations for the EntryAction and IterableEntryAction interface methods.
`protected class`	`SegmentedHashMap.EntrySet` A set of entries backed by this map.
`protected class`	`SegmentedHashMap.GetEntryAction` Action support for getEntryInternal.
`protected class`	`SegmentedHashMap.InsertAction` Action support for insert.
`protected static interface`	`SegmentedHashMap.IterableEntryAction` IterableEntryAction is an EntryAction that is suitable for applying to all keys in a map.
`protected class`	`SegmentedHashMap.KeySet` A set of entries backed by this map.
`protected class`	`SegmentedHashMap.RemoveAction` Action support for remove().
`protected static class`	`SegmentedHashMap.Segment` Segment metadata.
`protected class`	`SegmentedHashMap.ValuesCollection` A collection of values backed by this map.

Nested classes/interfaces inherited from class com.tangosol.util.Base
Base.LoggingWriter, Base.StackFrame

Field Summary

Fields
Modifier and Type	Field and Description
`protected static int`	`BIGGEST_MODULO` Biggest possible modulo.
`static float`	`DEFAULT_GROWTHRATE` Using the default growth rate, the bucket array will grow by a factor of four.
`static int`	`DEFAULT_INITIALSIZE` Default initial size provides a prime modulo and is large enough that resize is not immediate.
`static float`	`DEFAULT_LOADFACTOR` The default load factor is 100%, which means that the hash map will not resize until there is (on average) one entry in every bucket.
`protected static long`	`LOCK_ALL_PENDING` The bit-mask used to indicate that a lock-all is pending.
`protected static int`	`LOCK_ALL_PENDING_IDX` The mutex number used to indicate that a lock-all is pending.
`protected static int`	`LOCK_COUNT` The number of segment-locks.
`protected static long`	`LOCKS_ALL` The lock representation used to indicate that all mutexes are locked.
`protected static long`	`LOCKS_NONE` The lock representation used to indicate that no locks are set.
`protected SegmentedHashMap.ContainsValueAction`	`m_actionContainsValue` The singleton action for containsValue support.
`protected SegmentedHashMap.GetEntryAction`	`m_actionGetEntry` The singleton action for getEntryInternal support.
`protected SegmentedHashMap.InsertAction`	`m_actionInsert` The singleton action for insert support.
`protected SegmentedHashMap.RemoveAction`	`m_actionRemove` The singleton action for remove support.
`protected SegmentedHashMap.Entry[]`	`m_aeBucket` The array of hash buckets.
`protected SegmentedHashMap.Segment[]`	`m_aSegment` An array of the control-structures for the Map's segments.
`protected AtomicLong`	`m_atomicLocks` The "segment-locks".
`protected SegmentedHashMap.ValuesCollection`	`m_colValues` The collection of values backed by this map.
`protected int`	`m_cSegmentCapacity` The capacity of each segment (the point at which we should resize).
`protected float`	`m_flGrowthRate` The rate of growth as a fraction of the current number of buckets, 0 < n, such that the hash map grows to bucketcount * (1 + growth-rate).
`protected float`	`m_flLoadFactor` The determining factor for the hash map capacity given a certain number of buckets, such that capacity = bucketcount * loadfactor.
`protected Object`	`m_oIterActive` A holder for active Iterator(s): either WeakReference(<Iterator>) or WeakHashMap(<Iterator> null)
`protected SegmentedHashMap.EntrySet`	`m_setEntries` The set of entries backed by this map.
`protected SegmentedHashMap.KeySet`	`m_setKeys` The set of keys backed by this map.
`protected static int`	`MIN_SEGMENT_CAPACITY` The minimum segment capacity.
`protected static Object`	`NO_VALUE` Object to be used as a value representing that the Entry object is "synthetic" and while logically associated with a key, does not represent a key-value mapping in the Map.
`protected static int[]`	`PRIME_MODULO` A list of possible modulos to use.
`protected static int`	`PUTALL_THRESHOLD` Size threshold used by the putAll operation.
`protected Object`	`RESIZING` When resizing completes, a notification is issued against this object.
`protected static int`	`SEGMENT_COUNT` The number of segments to partition the hash buckets into.
`protected static int`	`SEGMENT_LOCK_MAX_SPIN` Maximum number of times to spin while trying to acquire a segment lock before waiting.

Fields inherited from class com.tangosol.util.Base
LOG_ALWAYS, LOG_DEBUG, LOG_ERR, LOG_INFO, LOG_MAX, LOG_MIN, LOG_QUIET, LOG_WARN, POWER_0, POWER_G, POWER_K, POWER_M, POWER_T, UNIT_D, UNIT_H, UNIT_M, UNIT_MS, UNIT_NS, UNIT_S, UNIT_US

Constructor Summary

Constructors
Constructor and Description
`SegmentedHashMap()` Default constructor.
`SegmentedHashMap(int cInitialBuckets, float flLoadFactor, float flGrowthRate)` Construct a thread-safe hash map using the specified settings.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Removes all mappings from this map.
`boolean`	`containsKey(Object oKey)` Returns `true` iff this map contains a mapping for the specified key.
`boolean`	`containsValue(Object oValue)` Returns `true` if this map maps one or more keys to the specified value.
`protected void`	`contendForSegment(int nSegment)` Wait for a segment to be unlocked.
`protected void`	`ensureLoadFactor(SegmentedHashMap.Segment segment)` Check whether or not the specified segment is overloaded and if so, grow the bucket array (which suggests with high probability that the per-segment load will decrease).
`protected static SegmentedHashMap.Entry`	`entryFromBucket(SegmentedHashMap.Entry[] aeBucket, int nBucket)` Return the first non-synthetic Entry object contained by in the specified bucket.
`Set`	`entrySet()` Returns a set view of the mappings contained in this map.
`boolean`	`equals(Object oThat)` Compares the specified object with this map for equality.
`Object`	`get(Object oKey)` Returns the value to which this map maps the specified key.
`protected int`	`getBucketIndex(int nHash, int cBuckets)` Calculate the bucket number for a particular hash code.
`protected SegmentedHashMap.ContainsValueAction`	`getContainsValueAction()` Return the registered action for containsValue().
`Map.Entry`	`getEntry(Object key)` Locate an Entry in the this map based on its key.
`protected SegmentedHashMap.Entry`	`getEntryInternal(Object oKey)` Locate an Entry in the hash map based on its key.
`protected SegmentedHashMap.Entry`	`getEntryInternal(Object oKey, boolean fSynthetic)` Locate an Entry in the hash map based on its key.
`protected SegmentedHashMap.GetEntryAction`	`getGetEntryAction()` Return the registered action for getEntryInternal.
`protected SegmentedHashMap.InsertAction`	`getInsertAction()` Return the registered action for insert.
`protected SegmentedHashMap.RemoveAction`	`getRemoveAction()` Return the registered action for remove().
`protected SegmentedHashMap.Segment`	`getSegmentForKey(Object oKey)` Return the Segment object for the specified key.
`protected int`	`getSegmentIndex(int nBucket)` Calculate the segment index for the the specified bucket.
`protected SegmentedHashMap.Entry[]`	`getStableBucketArray()` Get the bucket array, or if a resize is occurring, wait for the resize to complete and return the new bucket array.
`protected void`	`grow()` Resize the bucket array, rehashing all Entries.
`protected void`	`grow(int cNew)` Resize the bucket array to the specified size, rehashing all Entries.
`int`	`hashCode()` Returns the hash code value for this Map.
`protected void`	`initializeActions()` Initialize the EntryAction's for this map.
`protected SegmentedHashMap.ContainsValueAction`	`instantiateContainsValueAction()` Factory for ContainsValueAction
`protected SegmentedHashMap.Entry`	`instantiateEntry(Object oKey, Object oValue, int nHash)` Factory for Entry.
`protected SegmentedHashMap.EntrySet`	`instantiateEntrySet()` Factory for EntrySet
`protected SegmentedHashMap.GetEntryAction`	`instantiateGetEntryAction()` Factory for GetEntryAction
`protected SegmentedHashMap.InsertAction`	`instantiateInsertAction()` Factory for InsertAction
`protected SegmentedHashMap.KeySet`	`instantiateKeySet()` Factory for KeySet.
`protected SegmentedHashMap.RemoveAction`	`instantiateRemoveAction()` Factory for RemoveAction
`protected SegmentedHashMap.ValuesCollection`	`instantiateValuesCollection()` Factory for ValuesCollection.
`protected Object`	`invokeOnAllKeys(Object oContext, boolean fLock, SegmentedHashMap.IterableEntryAction actionEntry)` Perform an action on all Entries in the map.
`protected Object`	`invokeOnKey(Object oKey, Object oContext, boolean fLock, SegmentedHashMap.EntryAction action)` Perform an action on the specified key.
`protected boolean`	`isActiveIterator()` Determine if there are any active Iterators, which may mean that they are in the middle of iterating over the Map.
`boolean`	`isEmpty()` Returns `true` if this map contains no key-value mappings.
`protected void`	`iteratorActivated(Iterator iter)` Register the activation of an Iterator.
`Set`	`keySet()` Returns a Set view of the keys contained in this map.
`protected void`	`lockAllBuckets()` Lock everything.
`protected boolean`	`lockAllBuckets(int nBucketAlreadyLocked)` Lock everything, assuming that the segment for the specified bucket has already been locked.
`protected boolean`	`lockAllSegments(long lLocksHeld)` Lock all segments except for the specified segments that have already been locked by the calling thread.
`protected boolean`	`lockBucket(int nBucket)` Attempt to lock the segment corresponding to the specified bucket.
`protected boolean`	`lockSegment(int nSegment, boolean fBlock)` Attempt to lock the specified segment.
`Object`	`put(Object oKey, Object oValue)` Associates the specified value with the specified key in this map.
`void`	`putAll(Map mapOther)` Copies all of the mappings from the specified map to this map.
`protected Object`	`putInternal(Object oKey, Object oValue)` Associates the specified value with the specified key in this map.
`protected Object`	`putInternal(Object oKey, Object oValue, boolean fOnlyIfAbsent)` Associates the specified value with the specified key in this map.
`void`	`releaseIterator(Iterator iter)` Release the (formerly-active) Iterator.
`Object`	`remove(Object oKey)` Removes the mapping for this key from this map if present.
`protected Object`	`removeInternal(Object oKey, SegmentedHashMap.EntryAction actionRemove, Object oContext)` Removes the mapping for this key from this map if present.
`protected void`	`setContainsValueAction(SegmentedHashMap.ContainsValueAction action)` Specify the action for containsValue().
`protected void`	`setGetEntryAction(SegmentedHashMap.GetEntryAction action)` Specify the action for getEntryInternal.
`protected void`	`setInsertAction(SegmentedHashMap.InsertAction action)` Specify the action for insert.
`protected void`	`setRemoveAction(SegmentedHashMap.RemoveAction action)` Specify the action for remove().
`int`	`size()` Returns the number of key-value mappings in this map.
`protected Object[]`	`toArrayInternal(SegmentedHashMap.IterableEntryAction action, Object[] a)` Apply the specified toArray() action to the entries in the map.
`String`	`toString()` Returns a String representation of this map.
`protected void`	`unlockAllBuckets()` Unlock everything.
`protected void`	`unlockAllBuckets(int nBucketLeaveLocked)` Unlock everything, leaving only the segment for the specified bucket locked.
`protected void`	`unlockAllSegments(long lLocksKeep)` Unlock all segments, except the segment-locks indicated by the specified bit-vector.
`protected void`	`unlockBucket(int nBucket)` Unlock the segment corresponding to the specified bucket that was previously locked using the `lockBucket(int)` method.
`protected void`	`unlockSegment(int nSegment)` Unlock the specified segment previously locked using the `lockSegment(int, boolean)` method.
`Collection`	`values()` Returns a collection view of the values contained in this map.

Methods inherited from class com.tangosol.util.Base
azzert, azzert, azzert, azzertFailed, breakLines, breakLines, capitalize, checkNotEmpty, checkNotNull, checkRange, computeSafeWaitTime, decimalValue, dup, dup, ensureBigDecimal, ensureClassLoader, ensureRuntimeException, ensureRuntimeException, equals, equalsDeep, err, err, err, err, err, escape, formatDateTime, getCallerStackFrame, getCommonMonitor, getCommonMonitor, getCommonMonitor, getContextClassLoader, getContextClassLoader, getDeepMessage, getErr, getLastSafeTimeMillis, getLog, getMaxDecDigits, getMaxHexDigits, getOriginalException, getOut, getProcessRandom, getRandom, getRandomBinary, getRandomBinary, getRandomString, getSafeTimeMillis, getStackFrame, getStackFrames, getStackTrace, getStackTrace, getThreadFactory, getTimeZone, getUpTimeMillis, hashCode, hexValue, indentString, indentString, isDecimal, isHex, isLogEcho, isOctal, log, log, log, log, log, makeInteger, makeLong, makeThread, mod, mod, octalValue, out, out, out, out, out, pad, parseBandwidth, parseBandwidth, parseDelimitedString, parseHex, parseHex, parseMemorySize, parseMemorySize, parsePercentage, parseTime, parseTime, parseTimeNanos, parseTimeNanos, printStackTrace, randomize, randomize, randomize, randomize, read, read, read, read, read, read, read, replace, setErr, setLog, setLogEcho, setOut, sleep, toBandwidthString, toBandwidthString, toCharEscape, toCrc, toCrc, toCrc, toCrc, toCrc, toDecString, toDelimitedString, toDelimitedString, toDelimitedString, toDelimitedString, toHex, toHex, toHexDump, toHexEscape, toHexEscape, toHexEscape, toHexEscape, toHexString, toMemorySizeString, toMemorySizeString, toQuotedCharEscape, toQuotedStringEscape, toSqlString, toString, toString, toStringEscape, toUnicodeEscape, trace, trace, trace, trace, trace, trace, trace, trace, trace, truncateString, truncateString, wait

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map
compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

- Field Detail
  - PRIME_MODULO
```
protected static final int[] PRIME_MODULO
```
    A list of possible modulos to use.
  - DEFAULT_INITIALSIZE
```
public static final int DEFAULT_INITIALSIZE
```
    Default initial size provides a prime modulo and is large enough that resize is not immediate. (A hash map probably uses less than 128 bytes initially.)
  - BIGGEST_MODULO
```
protected static final int BIGGEST_MODULO
```
    Biggest possible modulo.
  - DEFAULT_LOADFACTOR
```
public static final float DEFAULT_LOADFACTOR
```
    The default load factor is 100%, which means that the hash map will not resize until there is (on average) one entry in every bucket. The cost of scanning a linked list in a particular bucket is very low, so there is little reason for having this value below 1.0, and the goal is constant order access, so assuming a perfect hash this will provide the optimal access speed relative to size.
    
    See Also:
    
    Constant Field Values
  - DEFAULT_GROWTHRATE
```
public static final float DEFAULT_GROWTHRATE
```
    Using the default growth rate, the bucket array will grow by a factor of four. The relatively high growth rate helps to ensure less resize operations, an important consideration in a high-concurrency map.
    
    See Also:
    
    Constant Field Values
  - MIN_SEGMENT_CAPACITY
```
protected static final int MIN_SEGMENT_CAPACITY
```
    The minimum segment capacity.
    
    See Also:
    
    Constant Field Values
  - SEGMENT_COUNT
```
protected static final int SEGMENT_COUNT
```
    The number of segments to partition the hash buckets into. There is a single lock for each segment. This number is specially chosen as 61 is the largest prime number smaller than 64 (the size of the datatype used to represent the lock).
    
    See Also:
    
    Constant Field Values
  - LOCK_COUNT
```
protected static final int LOCK_COUNT
```
    The number of segment-locks. Each segment has its own lock and there is a global "intention" lock.
    
    See Also:
    
    Constant Field Values
  - LOCKS_NONE
```
protected static final long LOCKS_NONE
```
    The lock representation used to indicate that no locks are set.
    
    See Also:
    
    Constant Field Values
  - LOCKS_ALL
```
protected static final long LOCKS_ALL
```
    The lock representation used to indicate that all mutexes are locked.
    
    See Also:
    
    Constant Field Values
  - LOCK_ALL_PENDING_IDX
```
protected static final int LOCK_ALL_PENDING_IDX
```
    The mutex number used to indicate that a lock-all is pending.
    
    See Also:
    
    Constant Field Values
  - LOCK_ALL_PENDING
```
protected static final long LOCK_ALL_PENDING
```
    The bit-mask used to indicate that a lock-all is pending.
    
    See Also:
    
    Constant Field Values
  - SEGMENT_LOCK_MAX_SPIN
```
protected static final int SEGMENT_LOCK_MAX_SPIN
```
    Maximum number of times to spin while trying to acquire a segment lock before waiting.
    
    See Also:
    
    Constant Field Values
  - PUTALL_THRESHOLD
```
protected static final int PUTALL_THRESHOLD
```
    Size threshold used by the putAll operation.
    
    See Also:
    
    Constant Field Values
  - NO_VALUE
```
protected static final Object NO_VALUE
```
    Object to be used as a value representing that the Entry object is "synthetic" and while logically associated with a key, does not represent a key-value mapping in the Map.
  - RESIZING
```
protected final Object RESIZING
```
    When resizing completes, a notification is issued against this object.
  - m_atomicLocks
```
protected final AtomicLong m_atomicLocks
```
    The "segment-locks". This AtomicCounter is actually used just as an "Atomic Long" value, with each of the first 61 bits being used to represent a segment-lock. In this case, the number of "buckets" is fixed to 61 (the largest prime smaller than 64).
  - m_aSegment
```
protected final SegmentedHashMap.Segment[] m_aSegment
```
    An array of the control-structures for the Map's segments.
  - m_aeBucket
```
protected volatile SegmentedHashMap.Entry[] m_aeBucket
```
    The array of hash buckets. This field is declared volatile in order to reduce synchronization.
  - m_cSegmentCapacity
```
protected int m_cSegmentCapacity
```
    The capacity of each segment (the point at which we should resize).
  - m_flLoadFactor
```
protected final float m_flLoadFactor
```
    The determining factor for the hash map capacity given a certain number of buckets, such that capacity = bucketcount * loadfactor.
  - m_flGrowthRate
```
protected final float m_flGrowthRate
```
    The rate of growth as a fraction of the current number of buckets, 0 < n, such that the hash map grows to bucketcount * (1 + growth-rate).
  - m_setEntries
```
protected SegmentedHashMap.EntrySet m_setEntries
```
    The set of entries backed by this map.
  - m_setKeys
```
protected SegmentedHashMap.KeySet m_setKeys
```
    The set of keys backed by this map.
  - m_colValues
```
protected SegmentedHashMap.ValuesCollection m_colValues
```
    The collection of values backed by this map.
  - m_oIterActive
```
protected Object m_oIterActive
```
    A holder for active Iterator(s): either WeakReference(<Iterator>) or WeakHashMap(<Iterator> null)
  - m_actionGetEntry
```
protected SegmentedHashMap.GetEntryAction m_actionGetEntry
```
    The singleton action for getEntryInternal support.
  - m_actionInsert
```
protected SegmentedHashMap.InsertAction m_actionInsert
```
    The singleton action for insert support.
  - m_actionRemove
```
protected SegmentedHashMap.RemoveAction m_actionRemove
```
    The singleton action for remove support.
  - m_actionContainsValue
```
protected SegmentedHashMap.ContainsValueAction m_actionContainsValue
```
    The singleton action for containsValue support.
- Constructor Detail
  - SegmentedHashMap
```
public SegmentedHashMap()
```
    Default constructor.
  - SegmentedHashMap
```
public SegmentedHashMap(int cInitialBuckets,
                        float flLoadFactor,
                        float flGrowthRate)
```
    Construct a thread-safe hash map using the specified settings.
    
    Parameters:
    
    cInitialBuckets - the initial number of hash buckets, 0 < n
    
    flLoadFactor - the acceptable load factor before resizing occurs, 0 < n, such that a load factor of 1.0 causes resizing when the number of entries exceeds the number of buckets
    
    flGrowthRate - the rate of bucket growth when a resize occurs, 0 < n, such that a growth rate of 1.0 will double the number of buckets: bucketcount = bucketcount * (1 + growthrate)
- Method Detail
  - getInsertAction
```
protected SegmentedHashMap.InsertAction getInsertAction()
```
    Return the registered action for insert.
    
    Returns:
    
    the registered action for insert
  - setInsertAction
```
protected void setInsertAction(SegmentedHashMap.InsertAction action)
```
    Specify the action for insert.
    
    Parameters:
    
    action - the action for insert
  - getGetEntryAction
```
protected SegmentedHashMap.GetEntryAction getGetEntryAction()
```
    Return the registered action for getEntryInternal.
    
    Returns:
    
    the registered action for getEntryInternal
  - setGetEntryAction
```
protected void setGetEntryAction(SegmentedHashMap.GetEntryAction action)
```
    Specify the action for getEntryInternal.
    
    Parameters:
    
    action - the action for getEntryInternal
  - getRemoveAction
```
protected SegmentedHashMap.RemoveAction getRemoveAction()
```
    Return the registered action for remove().
    
    Returns:
    
    the registered action for remove()
  - setRemoveAction
```
protected void setRemoveAction(SegmentedHashMap.RemoveAction action)
```
    Specify the action for remove().
    
    Parameters:
    
    action - the action for remove()
  - getContainsValueAction
```
protected SegmentedHashMap.ContainsValueAction getContainsValueAction()
```
    Return the registered action for containsValue().
    
    Returns:
    
    the registered action for containsValue()
  - setContainsValueAction
```
protected void setContainsValueAction(SegmentedHashMap.ContainsValueAction action)
```
    Specify the action for containsValue().
    
    Parameters:
    
    action - the action for containsValue()
  - equals
```
public boolean equals(Object oThat)
```
    Compares the specified object with this map for equality. Returns true if the given object is also a map and the two maps represent the same mappings. More formally, two maps t1 and t2 represent the same mappings if t1.keySet().equals(t2.keySet()) and for every key k in t1.keySet(), (t1.get(k)==null ? t2.get(k)==null : t1.get(k).equals(t2.get(k))). This ensures that the equals method works properly across different implementations of the map interface.
    
    Specified by:
    
    equals in interface Map
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    oThat - object to be compared for equality with this Map
    
    Returns:
    
    true if the specified object is equal to this Map
  - hashCode
```
public int hashCode()
```
    Returns the hash code value for this Map. The hash code of a Map is defined to be the sum of the hash codes of each entry in the Map's entrySet() view. This ensures that t1.equals(t2) implies that t1.hashCode()==t2.hashCode() for any two maps t1 and t2, as required by the general contract of Object.hashCode.
    
    Specified by:
    
    hashCode in interface Map
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    the hash code value for this Map
  - toString
```
public String toString()
```
    Returns a String representation of this map.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a String representation of this map
  - size
```
public int size()
```
    Returns the number of key-value mappings in this map.
    Note: Unlike some Map implementations, the size() operation on this map may be relatively expensive.
    
    Specified by:
    
    size in interface Map
    
    Returns:
    
    the number of key-value mappings in this map
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this map contains no key-value mappings.
    
    Specified by:
    
    isEmpty in interface Map
    
    Returns:
    
    true if this map contains no key-value mappings
  - containsKey
```
public boolean containsKey(Object oKey)
```
    Returns true iff this map contains a mapping for the specified key.
    
    Specified by:
    
    containsKey in interface Map
    
    Parameters:
    
    oKey - key whose presence in this map is to be tested
    
    Returns:
    
    true iff this map contains a mapping for the specified key
  - containsValue
```
public boolean containsValue(Object oValue)
```
    Returns true if this map maps one or more keys to the specified value.
    
    Specified by:
    
    containsValue in interface Map
    
    Parameters:
    
    oValue - value whose presence in this map is to be tested
    
    Returns:
    
    true if this map maps one or more keys to the specified value
  - get
```
public Object get(Object oKey)
```
    Returns the value to which this map maps the specified key. Returns null if the map contains no mapping for this key. A return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.
    
    Specified by:
    
    get in interface Map
    
    Parameters:
    
    oKey - key whose associated value is to be returned
    
    Returns:
    
    the value to which this map maps the specified key, or null if the map contains no mapping for this key
  - getEntry
```
public Map.Entry getEntry(Object key)
```
    Locate an Entry in the this map based on its key.
    
    Parameters:
    
    key - the key object to search for
    
    Returns:
    
    the Entry or null if the entry does not exist
  - put
```
public Object put(Object oKey,
                  Object oValue)
```
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.
    
    Specified by:
    
    put in interface Map
    
    Parameters:
    
    oKey - key with which the specified value is to be associated
    
    oValue - value to be associated with the specified key
    
    Returns:
    
    previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key
  - putAll
```
public void putAll(Map mapOther)
```
    Copies all of the mappings from the specified map to this map. putAll is semantically equivalent to:
```
 for (Iterator iter = mapOther.entrySet().iterator(); iter.hasNext(); )
     {
     Map.Entry entry = (Map.Entry) iter.next();
     put(entry.getKey(), entry.getValue());
     }
 
```
    Specified by:
    
    putAll in interface Map
    
    Parameters:
    
    mapOther - mappings to be stored in this map
  - remove
```
public Object remove(Object oKey)
```
    Removes the mapping for this key from this map if present.
    
    Specified by:
    
    remove in interface Map
    
    Parameters:
    
    oKey - key whose mapping is to be removed from the map
    
    Returns:
    
    previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key
  - clear
```
public void clear()
```
    Removes all mappings from this map.
    
    Specified by:
    
    clear in interface Map
  - entrySet
```
public Set entrySet()
```
    Returns a set view of the mappings contained in this map. Each element in the returned set is a Map.Entry. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.
    
    Specified by:
    
    entrySet in interface Map
    
    Returns:
    
    a set view of the mappings contained in this map.
  - keySet
```
public Set keySet()
```
    Returns a Set view of the keys contained in this map. The Set is backed by the map, so changes to the map are reflected in the Set, and vice-versa. (If the map is modified while an iteration over the Set is in progress, the results of the iteration are undefined.) The Set supports element removal, which removes the corresponding entry from the map, via the Iterator.remove, Set.remove, removeAll retainAll, and clear operations. It does not support the add or addAll operations.
    
    Specified by:
    
    keySet in interface Map
    
    Returns:
    
    a Set view of the keys contained in this map
  - values
```
public Collection values()
```
    Returns a collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.
    
    Specified by:
    
    values in interface Map
    
    Returns:
    
    a collection view of the values contained in this map
  - initializeActions
```
protected void initializeActions()
```
    Initialize the EntryAction's for this map.
  - getEntryInternal
```
protected SegmentedHashMap.Entry getEntryInternal(Object oKey)
```
    Locate an Entry in the hash map based on its key.
    
    Parameters:
    
    oKey - the key object to search for
    
    Returns:
    
    the Entry or null
  - getEntryInternal
```
protected SegmentedHashMap.Entry getEntryInternal(Object oKey,
                                                  boolean fSynthetic)
```
    Locate an Entry in the hash map based on its key.
    
    Parameters:
    
    oKey - the key object to search for
    
    fSynthetic - include synthetic Entry objects representing keys that are not contained in the map
    
    Returns:
    
    the Entry or null
  - putInternal
```
protected Object putInternal(Object oKey,
                             Object oValue)
```
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.
    
    Parameters:
    
    oKey - key with which the specified value is to be associated
    
    oValue - value to be associated with the specified key
    
    Returns:
    
    previous value associated with specified key, or NO_VALUE if there was no mapping for key. A null return indicates that the map previously associated null with the specified key
  - putInternal
```
protected Object putInternal(Object oKey,
                             Object oValue,
                             boolean fOnlyIfAbsent)
```
    Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.
    
    Parameters:
    
    oKey - key with which the specified value is to be associated
    
    oValue - value to be associated with the specified key
    
    fOnlyIfAbsent - if true, perform a logical insert only; no action if the key already exists
    
    Returns:
    
    previous value associated with specified key, or NO_VALUE if there was no mapping for key. A null return indicates that the map previously associated null with the specified key
  - removeInternal
```
protected Object removeInternal(Object oKey,
                                SegmentedHashMap.EntryAction actionRemove,
                                Object oContext)
```
    Removes the mapping for this key from this map if present.
    
    Parameters:
    
    oKey - key whose mapping is to be removed from the map
    
    actionRemove - the EntryAction to apply
    
    oContext - the context for the remove action
    
    Returns:
    
    previous value associated with specified key, or NO_VALUE if there was no mapping for key. A null return indicates that the map previously associated null with the specified key.
  - toArrayInternal
```
protected Object[] toArrayInternal(SegmentedHashMap.IterableEntryAction action,
                                   Object[] a)
```
    Apply the specified toArray() action to the entries in the map. The toArray() action is not applied under any segment lock and is expected to accept a List instance as a context.
    
    Parameters:
    
    action - the toArray() action
    
    a - the array into which the elements of the Collection are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose
    
    Returns:
    
    an array containing the elements returned by the specified action
    
    Throws:
    
    ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of the elements returned by the specified action
  - ensureLoadFactor
```
protected void ensureLoadFactor(SegmentedHashMap.Segment segment)
```
    Check whether or not the specified segment is overloaded and if so, grow the bucket array (which suggests with high probability that the per-segment load will decrease).
    
    Parameters:
    
    segment - the segment to ensure the load-factor for
  - grow
```
protected void grow()
```
    Resize the bucket array, rehashing all Entries.
    Note: caller of this method is expected to hold locks on all segments of the map while making this call.
  - grow
```
protected void grow(int cNew)
```
    Resize the bucket array to the specified size, rehashing all Entries.
    Note: caller of this method is expected to hold locks on all segments of the map while making this call.
    
    Parameters:
    
    cNew - the minimum size to attempt to grow to
  - invokeOnAllKeys
```
protected Object invokeOnAllKeys(Object oContext,
                                 boolean fLock,
                                 SegmentedHashMap.IterableEntryAction actionEntry)
```
    Perform an action on all Entries in the map. The action is provided as an EntryAction and (if the fLock is specified) it are invoked while holding the locks for all segments.
    The semantics of invokeOnAllKeys are equivalent to:
```
 for (Iterator iter = entrySet().iterator(); iter.hasNext(); )
     {
     Entry entry = (Entry) iter.next();
     actionEntry.invokeFound(...);
     }
 return oContext;
 
```
    Except that if fLock is specified, it is performed atomically while holding all segment-locks.
    Parameters:
    
    oContext - opaque context for the specified action
    
    fLock - true if all segment-locks should be acquired before invoking the specified action
    
    actionEntry - the action to perform for each entry
    
    Returns:
    
    the specified opaque context
  - invokeOnKey
```
protected Object invokeOnKey(Object oKey,
                             Object oContext,
                             boolean fLock,
                             SegmentedHashMap.EntryAction action)
```
    Perform an action on the specified key. The action operation is provided as an EntryAction and (if fLock is specified), is invoked while holding the appropriate segment lock for the key.
    The semantics of invokeOnKey are equivalent to:
```
 Object oResult;
 if (containsKey(oKey))
     {
     oResult = action.invokeFound(...);
     }
 else
     {
     oResult = action.invokeNotFound(...);
     }
 return oResult;
 
```
    Except that if fLock is specified, it is performed atomically while holding the segment-lock.
    Parameters:
    
    oKey - the key to act on
    
    oContext - opaque context for the specified action
    
    fLock - true iff the segment should be locked before invoking the specified action
    
    action - the action to invoke
    
    Returns:
    
    the result of performing the action
  - getBucketIndex
```
protected int getBucketIndex(int nHash,
                             int cBuckets)
```
    Calculate the bucket number for a particular hash code.
    
    Parameters:
    
    nHash - the hash code
    
    cBuckets - the number of buckets
    
    Returns:
    
    the bucket index for the specified hash code
  - getSegmentIndex
```
protected int getSegmentIndex(int nBucket)
```
    Calculate the segment index for the the specified bucket.
    
    Parameters:
    
    nBucket - the bucket number
    
    Returns:
    
    the segment index
  - getSegmentForKey
```
protected SegmentedHashMap.Segment getSegmentForKey(Object oKey)
```
    Return the Segment object for the specified key.
    
    Parameters:
    
    oKey - the key
    
    Returns:
    
    the Segment for the specified key
  - getStableBucketArray
```
protected SegmentedHashMap.Entry[] getStableBucketArray()
```
    Get the bucket array, or if a resize is occurring, wait for the resize to complete and return the new bucket array.
    
    Returns:
    
    the latest bucket array
  - iteratorActivated
```
protected void iteratorActivated(Iterator iter)
```
    Register the activation of an Iterator.
    Note: The map will not grow while there are any active iterators.
    
    Parameters:
    
    iter - the activated iterator
  - releaseIterator
```
public void releaseIterator(Iterator iter)
```
    Release the (formerly-active) Iterator.
    Note: This method could be used to accelerate the destruction of unexhausted iterators.
    
    Parameters:
    
    iter - the iterator to be released
  - isActiveIterator
```
protected boolean isActiveIterator()
```
    Determine if there are any active Iterators, which may mean that they are in the middle of iterating over the Map.
    
    Returns:
    
    true iff there is at least one active Iterator
  - lockBucket
```
protected boolean lockBucket(int nBucket)
```
    Attempt to lock the segment corresponding to the specified bucket.
    
    Parameters:
    
    nBucket - the bucket index
    
    Returns:
    
    true iff the segment was successfully locked
  - lockSegment
```
protected boolean lockSegment(int nSegment,
                              boolean fBlock)
```
    Attempt to lock the specified segment.
    
    Parameters:
    
    nSegment - the segment to lock
    
    fBlock - should we block on trying to lock the segment
    
    Returns:
    
    true iff the segment was successfully locked
  - unlockBucket
```
protected void unlockBucket(int nBucket)
```
    Unlock the segment corresponding to the specified bucket that was previously locked using the lockBucket(int) method.
    
    Parameters:
    
    nBucket - the bucket to unlock
  - unlockSegment
```
protected void unlockSegment(int nSegment)
```
    Unlock the specified segment previously locked using the lockSegment(int, boolean) method.
    
    Parameters:
    
    nSegment - the segment to unlock
  - contendForSegment
```
protected void contendForSegment(int nSegment)
```
    Wait for a segment to be unlocked.
    
    Parameters:
    
    nSegment - the segment-lock to be waited for
  - lockAllBuckets
```
protected void lockAllBuckets()
```
    Lock everything. This method will not return until the lock is placed. It must not be called on a thread that could already hold a lock.
  - lockAllBuckets
```
protected boolean lockAllBuckets(int nBucketAlreadyLocked)
```
    Lock everything, assuming that the segment for the specified bucket has already been locked.
    
    Parameters:
    
    nBucketAlreadyLocked - the bucket that was already locked.
    
    Returns:
    
    false if the operation failed because another thread was also trying to lock everything (indicating potential deadlock)
  - unlockAllBuckets
```
protected void unlockAllBuckets()
```
    Unlock everything.
  - unlockAllBuckets
```
protected void unlockAllBuckets(int nBucketLeaveLocked)
```
    Unlock everything, leaving only the segment for the specified bucket locked.
    
    Parameters:
    
    nBucketLeaveLocked - the bucket that was already locked
  - lockAllSegments
```
protected boolean lockAllSegments(long lLocksHeld)
```
    Lock all segments except for the specified segments that have already been locked by the calling thread.
    
    Parameters:
    
    lLocksHeld - the bit-mask representing all segment-locks that the calling thread already holds
    
    Returns:
    
    false if the operation failed because another thread was also trying to lock everything (indicating potential deadlock)
  - unlockAllSegments
```
protected void unlockAllSegments(long lLocksKeep)
```
    Unlock all segments, except the segment-locks indicated by the specified bit-vector. This method must only be called by a thread if that thread has successfully called lockAllSegments(long).
    
    Parameters:
    
    lLocksKeep - the segment-locks to keep locked
  - instantiateGetEntryAction
```
protected SegmentedHashMap.GetEntryAction instantiateGetEntryAction()
```
    Factory for GetEntryAction
    
    Returns:
    
    a GetEntryAction
  - instantiateInsertAction
```
protected SegmentedHashMap.InsertAction instantiateInsertAction()
```
    Factory for InsertAction
    
    Returns:
    
    an InsertAction
  - instantiateRemoveAction
```
protected SegmentedHashMap.RemoveAction instantiateRemoveAction()
```
    Factory for RemoveAction
    
    Returns:
    
    a RemoveAction
  - instantiateContainsValueAction
```
protected SegmentedHashMap.ContainsValueAction instantiateContainsValueAction()
```
    Factory for ContainsValueAction
    
    Returns:
    
    a ContainsValueAction
  - instantiateEntry
```
protected SegmentedHashMap.Entry instantiateEntry(Object oKey,
                                                  Object oValue,
                                                  int nHash)
```
    Factory for Entry.
    
    Parameters:
    
    oKey - the key
    
    oValue - the value
    
    nHash - the hashCode value of the key
    
    Returns:
    
    a new instance of the Entry class (or a subclass thereof)
  - entryFromBucket
```
protected static SegmentedHashMap.Entry entryFromBucket(SegmentedHashMap.Entry[] aeBucket,
                                                        int nBucket)
```
    Return the first non-synthetic Entry object contained by in the specified bucket.
    
    Parameters:
    
    aeBucket - the array of hash buckets
    
    nBucket - the bucket index
    
    Returns:
    
    the first non-synthetic Entry in the specified bucket or null
  - instantiateEntrySet
```
protected SegmentedHashMap.EntrySet instantiateEntrySet()
```
    Factory for EntrySet
    
    Returns:
    
    a new instance of the EntrySet class (or a subclass thereof)
  - instantiateKeySet
```
protected SegmentedHashMap.KeySet instantiateKeySet()
```
    Factory for KeySet.
    
    Returns:
    
    a new instance of the KeySet class (or subclass thereof)
  - instantiateValuesCollection
```
protected SegmentedHashMap.ValuesCollection instantiateValuesCollection()
```
    Factory for ValuesCollection.
    
    Returns:
    
    a new instance of the ValuesCollection class (or subclass thereof)

Class SegmentedHashMap

Nested Class Summary

Nested classes/interfaces inherited from class com.tangosol.util.Base

Field Summary

Fields inherited from class com.tangosol.util.Base

Constructor Summary

Method Summary

Methods inherited from class com.tangosol.util.Base

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Map

Field Detail

PRIME_MODULO

DEFAULT_INITIALSIZE

BIGGEST_MODULO

DEFAULT_LOADFACTOR

DEFAULT_GROWTHRATE

MIN_SEGMENT_CAPACITY

SEGMENT_COUNT

LOCK_COUNT

LOCKS_NONE

LOCKS_ALL

LOCK_ALL_PENDING_IDX

LOCK_ALL_PENDING

SEGMENT_LOCK_MAX_SPIN

PUTALL_THRESHOLD

NO_VALUE

RESIZING

m_atomicLocks

m_aSegment

m_aeBucket

m_cSegmentCapacity

m_flLoadFactor

m_flGrowthRate

m_setEntries

m_setKeys

m_colValues

m_oIterActive

m_actionGetEntry

m_actionInsert

m_actionRemove

m_actionContainsValue

Constructor Detail

SegmentedHashMap

SegmentedHashMap

Method Detail

getInsertAction

setInsertAction

getGetEntryAction

setGetEntryAction

getRemoveAction

setRemoveAction

getContainsValueAction

setContainsValueAction

equals

hashCode

toString

size

isEmpty

containsKey

containsValue

get

getEntry

put

putAll

remove

clear

entrySet

keySet

values

initializeActions

getEntryInternal

getEntryInternal

putInternal

putInternal

removeInternal

toArrayInternal

ensureLoadFactor

grow

grow

invokeOnAllKeys