Oracle® Coherence Java API Reference
v3.5

E14977-01

com.tangosol.util
Class InvocableMapHelper.SimpleEntry

java.lang.Object
  extended by com.tangosol.util.Base
      extended by com.tangosol.util.InvocableMapHelper.SimpleEntry
All Implemented Interfaces:
InvocableMap.Entry, QueryMap.Entry, java.util.Map.Entry
Enclosing class:
InvocableMapHelper

public static class InvocableMapHelper.SimpleEntry
extends Base
implements InvocableMap.Entry

Simple implementation of the InvocableMap.Entry interface. This assumes that the underlying Map content does not change while a reference to the SimpleEntry is alive and may cache the entry's value to avoid an extra map lookup.


Field Summary
protected  java.util.Map m_map
          The map.
 
Constructor Summary
InvocableMapHelper.SimpleEntry(java.util.Map map, java.lang.Object oKey, boolean fReadOnly)
          Construct a SimpleEntry for a given map and a key.
InvocableMapHelper.SimpleEntry(java.lang.Object oKey, java.lang.Object oValue)
          Construct a SimpleEntry for a given key and value.
 
Method Summary
protected  void checkMutable()
          Verify that this SimpleEntry is mutable.
 boolean equals(java.lang.Object o)
          Compare this SimpleEntry with another object for equality.
 java.lang.Object extract(ValueExtractor extractor)
          Extract a value out of the Entry's value.
 java.lang.Object getKey()
          Return the key corresponding to this entry.
 java.lang.Object getValue()
          Return the value corresponding to this entry.
 int hashCode()
          Return a hash code value for the SimpleEntry object.
 boolean isPresent()
          Determine if this Entry exists in the Map.
 void remove(boolean fSynthetic)
          Remove this Entry from the Map if it is present in the Map.
 java.lang.Object setValue(java.lang.Object oValue)
          Store the value corresponding to this entry.
 void setValue(java.lang.Object oValue, boolean fSynthetic)
          Store the value corresponding to this entry.
 java.lang.String toString()
          Provide a human-readable representation of the SimpleEntry object.
 void update(ValueUpdater updater, java.lang.Object oValue)
          Update the Entry's value.
 

Field Detail

m_map

protected java.util.Map m_map
The map.

Constructor Detail

InvocableMapHelper.SimpleEntry

public InvocableMapHelper.SimpleEntry(java.util.Map map,
                                      java.lang.Object oKey,
                                      boolean fReadOnly)
Construct a SimpleEntry for a given map and a key.

Parameters:
map - the parent Map for this entry
oKey - the entry's key
fReadOnly - if true, the entry will be marked as read-only, preventing the setValue() and remove() methods from modifying the underlying map's content

InvocableMapHelper.SimpleEntry

public InvocableMapHelper.SimpleEntry(java.lang.Object oKey,
                                      java.lang.Object oValue)
Construct a SimpleEntry for a given key and value. The entry will be marked as read-only.

Parameters:
oKey - the entry's key
oValue - the entry's value
Method Detail

getKey

public java.lang.Object getKey()
Return the key corresponding to this entry. The resultant key does not necessarily exist within the containing Map, which is to say that InvocableMap.this.containsKey(getKey()) could return false. To test for the presence of this key within the Map, use InvocableMap.Entry.isPresent(), and to create the entry for the key, use InvocableMap.Entry.setValue(java.lang.Object).

Specified by:
getKey in interface InvocableMap.Entry
Specified by:
getKey in interface java.util.Map.Entry
Returns:
the key corresponding to this entry; may be null if the underlying Map supports null keys

getValue

public java.lang.Object getValue()
Return the value corresponding to this entry. If the entry does not exist, then the value will be null. To differentiate between a null value and a non-existent entry, use InvocableMap.Entry.isPresent().

Note: any modifications to the value retrieved using this method are not guaranteed to persist unless followed by a InvocableMap.Entry.setValue(java.lang.Object) or InvocableMap.Entry.update(com.tangosol.util.ValueUpdater, java.lang.Object) call.

Specified by:
getValue in interface InvocableMap.Entry
Specified by:
getValue in interface java.util.Map.Entry
Returns:
the value corresponding to this entry; may be null if the value is null or if the Entry does not exist in the Map

setValue

public java.lang.Object setValue(java.lang.Object oValue)
Store the value corresponding to this entry. If the entry does not exist, then the entry will be created by invoking this method, even with a null value (assuming the Map supports null values).

Specified by:
setValue in interface InvocableMap.Entry
Specified by:
setValue in interface java.util.Map.Entry
Parameters:
oValue - the new value for this Entry
Returns:
the previous value of this Entry, or null if the Entry did not exist

setValue

public void setValue(java.lang.Object oValue,
                     boolean fSynthetic)
Store the value corresponding to this entry. If the entry does not exist, then the entry will be created by invoking this method, even with a null value (assuming the Map supports null values).

Unlike the other form of setValue, this form does not return the previous value, and as a result may be significantly less expensive (in terms of cost of execution) for certain Map implementations.

Specified by:
setValue in interface InvocableMap.Entry
Parameters:
oValue - the new value for this Entry
fSynthetic - pass true only if the insertion into or modification of the Map should be treated as a synthetic event

extract

public java.lang.Object extract(ValueExtractor extractor)
Extract a value out of the Entry's value. Calling this method is semantically equivalent to extractor.extract(entry.getValue()), but this method may be significantly less expensive. For example, the resultant value may be obtained from a forward index, avoiding a potential object de-serialization.

Specified by:
extract in interface QueryMap.Entry
Parameters:
extractor - a ValueExtractor to apply to the Entry's value
Returns:
the extracted value

update

public void update(ValueUpdater updater,
                   java.lang.Object oValue)
Update the Entry's value. Calling this method is semantically equivalent to:
   Object oTarget = entry.getValue();
   updater.update(oTarget, oValue);
   entry.setValue(oTarget, false);
 
The benefit of using this method is that it may allow the Entry implementation to significantly optimize the operation, such as for purposes of delta updates and backup maintenance.

Specified by:
update in interface InvocableMap.Entry
Parameters:
updater - a ValueUpdater used to modify the Entry's value
oValue - the new value for this Entry

isPresent

public boolean isPresent()
Determine if this Entry exists in the Map. If the Entry is not present, it can be created by calling InvocableMap.Entry.setValue(java.lang.Object) or InvocableMap.Entry.setValue(java.lang.Object). If the Entry is present, it can be destroyed by calling InvocableMap.Entry.remove(boolean).

Specified by:
isPresent in interface InvocableMap.Entry
Returns:
true iff this Entry is existent in the containing Map

remove

public void remove(boolean fSynthetic)
Remove this Entry from the Map if it is present in the Map.

This method supports both the operation corresponding to Map.remove(java.lang.Object) as well as synthetic operations such as eviction. If the containing Map does not differentiate between the two, then this method will always be identical to InvocableMap.this.remove(getKey()).

Specified by:
remove in interface InvocableMap.Entry
Parameters:
fSynthetic - pass true only if the removal from the Map should be treated as a synthetic event

equals

public boolean equals(java.lang.Object o)
Compare this SimpleEntry with another object for equality.

Specified by:
equals in interface java.util.Map.Entry
Parameters:
o - an object reference or null
Returns:
true iff the passed object reference is a SimpleEntry object with the same key

hashCode

public int hashCode()
Return a hash code value for the SimpleEntry object.

Specified by:
hashCode in interface java.util.Map.Entry

toString

public java.lang.String toString()
Provide a human-readable representation of the SimpleEntry object.

Returns:
a String representation of this SimpleEntry object

checkMutable

protected void checkMutable()
Verify that this SimpleEntry is mutable.


Oracle® Coherence Java API Reference
v3.5

E14977-01

Copyright © 2000, 2009, Oracle. All rights reserved.