com.tangosol.util
Class WrapperObservableMap

java.lang.Object
  com.tangosol.util.Base
      com.tangosol.util.AbstractKeyBasedMap
          com.tangosol.util.AbstractKeySetBasedMap
              com.tangosol.util.WrapperObservableMap

All Implemented Interfaces:

ObservableMap, Map

Direct Known Subclasses:

WrapperConcurrentMap

public class WrapperObservableMap
extends AbstractKeySetBasedMap
implements ObservableMap

A simple implementation of ObservableMap interface built as a wrapper around any Map implementation. It also provides an implementation of CacheStatistics interface.

Note: as of Coherence 3.0 the CacheStatistics implementation has to be turned on explicitly by calling the setCollectStats(boolean) method.

Note: if the underlying (wrapped) Map is an ObservableMap by itself, as of Coherence 3.2 the WrapperObservableMap implementation does not translate events generated the wrapped map by default. The translation can be turned on explicitly by calling the setTranslateEvents(boolean) method.

Since:

Coherence 2.3

Author:

gg 2003.10.01

Nested Class Summary

protected class

WrapperObservableMap.InternalListener An internal MapListener that listens to the wrapped map.

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

AbstractKeySetBasedMap.EntrySet, AbstractKeySetBasedMap.KeyIterator, AbstractKeySetBasedMap.KeySet, AbstractKeySetBasedMap.ValuesCollection

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry

Field Summary

protected MapListener	m_listenerInternal The MapListener used to listen to the wrapped ObservableMap.
protected MapListenerSupport	m_listenerSupport The event listeners.
protected Map	m_map The (wrapped) map containing all the resources.
protected SimpleCacheStatistics	m_stats The CacheStatistics object maintained by this wrapper.

Constructor Summary

WrapperObservableMap(Map map)
Construct an ObservableMap wrapper base on the specified map.

Method Summary

void	addMapListener(MapListener listener) Add a standard map listener that will receive all events (inserts, updates, deletes) that occur against the map, with the key, old-value and new-value included.
void	addMapListener(MapListener listener, Filter filter, boolean fLite) Add a map listener that receives events based on a filter evaluation.
void	addMapListener(MapListener listener, Object oKey, boolean fLite) Add a map listener for a specific key.
void	clear() Clear all key/value mappings.
boolean	containsValue(Object oValue) Returns true if this Map maps one or more keys to the specified value.
protected void	dispatchEvent(MapEvent evt) Dispatch the passed event.
protected void	dispatchPendingEvent(Object oKey, int nId, Object oNewValue, boolean fSynthetic) Dispatch an event that has not yet occurred, allowing the cache to potentially avoid reading of the "original value" information.
Object	get(Object oKey) Returns the value to which this map maps the specified key.
CacheStatistics	getCacheStatistics() Return the CacheStatistics for this cache.
protected String	getDescription() Assemble a human-readable description.
protected Set	getInternalKeySet() Obtain a set of keys that are represented by this Map.
Map	getMap() Get the Map that is wrapped by this wrapper.
protected MapListenerSupport	getMapListenerSupport() Accessor for the MapListenerSupport for sub-classes.
protected boolean	hasListeners() Determine if the OverflowMap has any listeners at all.
protected MapListener	instantiateInternalListener() Instantiate a MapListener to listen to the wrapped map.
boolean	isCollectStats() Check whether or not statistics are collected by the wrapper.
protected boolean	isEventFabricator() Determine if this ObservableMap has to fabricate events itself.
protected boolean	isInternalKeySetIteratorMutable() Determine if this Iterator should remove an iterated item by calling remove on the internal key Set Iterator, or by calling removeBlind on the map itself.
protected static boolean	isSynthetic(MapEvent evt) Helper method to determine if an event is synthetic.
boolean	isTranslateEvents() Check whether or not an event source has to be translated by the wrapper.
Object	put(Object oKey, Object oValue) Associates the specified value with the specified key in this map.
void	putAll(Map map) Copies all of the mappings from the specified map to this map.
Object	remove(Object oKey) Removes the mapping for this key from this map if present.
protected boolean	removeBlind(Object oKey) Removes the mapping for this key from this map if present.
void	removeMapListener(MapListener listener) Remove a standard map listener that previously signed up for all events.
void	removeMapListener(MapListener listener, Filter filter) Remove a map listener that previously signed up for events based on a filter evaluation.
void	removeMapListener(MapListener listener, Object oKey) Remove a map listener that previously signed up for events about a specific key.
void	setCollectStats(boolean fCollectStats) Specify whether or not statistics are to be collected by the wrapper.
void	setTranslateEvents(boolean fTranslate) Specify whether or not an event source has to be translated by the wrapper.
String	toString() Returns a string representation of this Map.

Methods inherited from class com.tangosol.util.AbstractKeySetBasedMap

containsKey, instantiateEntrySet, instantiateKeyIterator, instantiateKeySet, instantiateValues, isEmpty, iterateKeys, size

Methods inherited from class com.tangosol.util.AbstractKeyBasedMap

clone, entrySet, equals, getAll, hashCode, keySet, values

Methods inherited from interface java.util.Map

containsKey, entrySet, equals, hashCode, isEmpty, keySet, size, values

Field Detail

m_map

protected Map m_map

The (wrapped) map containing all the resources.

m_listenerSupport

protected MapListenerSupport m_listenerSupport

The event listeners.

m_listenerInternal

protected MapListener m_listenerInternal

The MapListener used to listen to the wrapped ObservableMap.

m_stats

protected SimpleCacheStatistics m_stats

The CacheStatistics object maintained by this wrapper.

Constructor Detail

WrapperObservableMap

public WrapperObservableMap(Map map)

Construct an ObservableMap wrapper base on the specified map.

Note: it is assumed that while the WrapperObservableMap exists, there is no direct manipulation with the content of the wrapped map.

Parameters:

map - the Map that will be wrapped by this WrapperObservableMap

Method Detail

clear

public void clear()

Clear all key/value mappings.

Specified by:

clear in interface Map

Overrides:

clear in class AbstractKeyBasedMap

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

Overrides:

containsValue in class AbstractKeyBasedMap

Returns:

true if this Map maps one or more keys to the specified value, false otherwise

get

public Object get(Object oKey)

Returns the value to which this map maps the specified key.

Specified by:

get in interface Map

Specified by:

get in class AbstractKeyBasedMap

Parameters:

oKey - the key object

Returns:

the value to which this map maps the specified key, or null if the map contains no mapping for this key

put

public Object put(Object oKey,
                  Object oValue)

Associates the specified value with the specified key in this map.

Specified by:

put in interface Map

Overrides:

put in class AbstractKeyBasedMap

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

putAll

public void putAll(Map map)

Copies all of the mappings from the specified map to this map. The effect of this call is equivalent to that of calling AbstractKeyBasedMap.put(java.lang.Object, java.lang.Object) on this map once for each mapping in the passed map. The behavior of this operation is unspecified if the passed map is modified while the operation is in progress.

Specified by:

putAll in interface Map

Overrides:

putAll in class AbstractKeyBasedMap

Parameters:

map - the Map containing the key/value pairings to put into this Map

remove

public Object remove(Object oKey)

Removes the mapping for this key from this map if present. Expensive: updates both the underlying cache and the local cache.

Specified by:

remove in interface Map

Overrides:

remove in class AbstractKeyBasedMap

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, if the implementation supports null values.

getInternalKeySet

protected Set getInternalKeySet()

Obtain a set of keys that are represented by this Map.

The AbstractKeySetBasedMap only utilizes the internal key set as a read-only resource.

Specified by:

getInternalKeySet in class AbstractKeySetBasedMap

Returns:

an internal Set of keys that are contained by this Map

isInternalKeySetIteratorMutable

protected boolean isInternalKeySetIteratorMutable()

Determine if this Iterator should remove an iterated item by calling remove on the internal key Set Iterator, or by calling removeBlind on the map itself.

Overrides:

isInternalKeySetIteratorMutable in class AbstractKeySetBasedMap

Returns:

true to remove using the internal key Set Iterator or false to use the AbstractKeyBasedMap.removeBlind(Object) method

removeBlind

protected boolean removeBlind(Object oKey)

Removes the mapping for this key from this map if present. This method exists to allow sub-classes to optmiize remove functionalitly for situations in which the original value is not required.

Overrides:

removeBlind in class AbstractKeyBasedMap

Parameters:

oKey - key whose mapping is to be removed from the map

Returns:

true iff the Map changed as the result of this operation

addMapListener

public void addMapListener(MapListener listener)

Add a standard map listener that will receive all events (inserts, updates, deletes) that occur against the map, with the key, old-value and new-value included. This has the same result as the following call:

   addMapListener(listener, (Filter) null, false);
 

Specified by:

addMapListener in interface ObservableMap

Parameters:

listener - the MapEvent listener to add

removeMapListener

public void removeMapListener(MapListener listener)

Remove a standard map listener that previously signed up for all events. This has the same result as the following call:

   removeMapListener(listener, (Filter) null);
 

Specified by:

removeMapListener in interface ObservableMap

Parameters:

listener - the listener to remove

addMapListener

public void addMapListener(MapListener listener,
                           Object oKey,
                           boolean fLite)

Add a map listener for a specific key.

The listeners will receive MapEvent objects, but if fLite is passed as true, they might not contain the OldValue and NewValue properties.

To unregister the MapListener, use the ObservableMap.removeMapListener(MapListener, Object) method.

Specified by:

addMapListener in interface ObservableMap

Parameters:

listener - the MapEvent listener to add

oKey - the key that identifies the entry for which to raise events

fLite - true to indicate that the MapEvent objects do not have to include the OldValue and NewValue property values in order to allow optimizations

removeMapListener

public void removeMapListener(MapListener listener,
                              Object oKey)

Remove a map listener that previously signed up for events about a specific key.

Specified by:

removeMapListener in interface ObservableMap

Parameters:

listener - the listener to remove

oKey - the key that identifies the entry for which to raise events

addMapListener

public void addMapListener(MapListener listener,
                           Filter filter,
                           boolean fLite)

Add a map listener that receives events based on a filter evaluation.

The listeners will receive MapEvent objects, but if fLite is passed as true, they might not contain the OldValue and NewValue properties.

To unregister the MapListener, use the ObservableMap.removeMapListener(MapListener, Filter) method.

Specified by:

addMapListener in interface ObservableMap

Parameters:

listener - the MapEvent listener to add

filter - a filter that will be passed MapEvent objects to select from; a MapEvent will be delivered to the listener only if the filter evaluates to true for that MapEvent (see MapEventFilter); null is equivalent to a filter that alway returns true

fLite - true to indicate that the MapEvent objects do not have to include the OldValue and NewValue property values in order to allow optimizations

removeMapListener

public void removeMapListener(MapListener listener,
                              Filter filter)

Remove a map listener that previously signed up for events based on a filter evaluation.

Specified by:

removeMapListener in interface ObservableMap

Parameters:

listener - the listener to remove

filter - the filter that was passed into the corresponding addMapListener() call

getMap

public Map getMap()

Get the Map that is wrapped by this wrapper.

Note: direct modifications of the returned map may cause an unpredictable behavior of the wrapper map.

Returns:

the wrapped Map

getCacheStatistics

public CacheStatistics getCacheStatistics()

Return the CacheStatistics for this cache.

Returns:

a CacheStatistics object

isCollectStats

public boolean isCollectStats()

Check whether or not statistics are collected by the wrapper.

Returns:

true if this wrapper collects cache statistics; false otherwise

Since:

Coherence 3.0

setCollectStats

public void setCollectStats(boolean fCollectStats)

Specify whether or not statistics are to be collected by the wrapper.

Parameters:

fCollectStats - true if this wrapper should collect cache statistics; false otherwise

Since:

Coherence 3.0

isTranslateEvents

public boolean isTranslateEvents()

Check whether or not an event source has to be translated by the wrapper.

Note: this setting is only meaningful if the underlying map is an ObservableMap itself.

Returns:

true if this wrapper translates an event source; false otherwise

Since:

Coherence 3.3

setTranslateEvents

public void setTranslateEvents(boolean fTranslate)

Specify whether or not an event source has to be translated by the wrapper.

Note: this setting is only meaningful if the underlying map is an ObservableMap itself.

Parameters:

fTranslate - true if this wrapper should translate an event source; false otherwise

Since:

Coherence 3.3

getDescription

protected String getDescription()

Assemble a human-readable description.

Returns:

a description of this Map

toString

public String toString()

Returns a string representation of this Map. The string representation consists of a list of key-value mappings in the order returned by the Map's entrySet view's iterator, enclosed in braces ("{}"). Adjacent mappings are separated by the characters ", " (comma and space). Each key-value mapping is rendered as the key followed by an equals sign ("=") followed by the associated value. Keys and values are converted to strings as by String.valueOf(Object).

Overrides:

toString in class AbstractKeyBasedMap

Returns:

a String representation of this Map

getMapListenerSupport

protected MapListenerSupport getMapListenerSupport()

Accessor for the MapListenerSupport for sub-classes.

Returns:

the MapListenerSupport, or null if there are no listeners

hasListeners

protected boolean hasListeners()

Determine if the OverflowMap has any listeners at all.

Returns:

true iff this OverflowMap has at least one MapListener

isEventFabricator

protected boolean isEventFabricator()

Determine if this ObservableMap has to fabricate events itself.

Returns:

true if events are expected, but the wrapped Map does not generate any events itself

isSynthetic

protected static boolean isSynthetic(MapEvent evt)

Helper method to determine if an event is synthetic.

Parameters:

evt - a Map Event

Returns:

true if the event is a synthetic cache event

dispatchPendingEvent

protected void dispatchPendingEvent(Object oKey,
                                    int nId,
                                    Object oNewValue,
                                    boolean fSynthetic)

Dispatch an event that has not yet occurred, allowing the cache to potentially avoid reading of the "original value" information.

Parameters:

oKey - the key which the event is related to

nId - the event ID

oNewValue - the new value

fSynthetic - true if the event is synthetic

dispatchEvent

protected void dispatchEvent(MapEvent evt)

Dispatch the passed event.

Parameters:

evt - a CacheEvent object

instantiateInternalListener

protected MapListener instantiateInternalListener()

Instantiate a MapListener to listen to the wrapped map.

Returns:

an instance of MapListener