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com.tangosol.util.processor
Class ConditionalPutAll

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.processor.AbstractProcessor
com.tangosol.util.processor.ConditionalPutAll

All Implemented Interfaces:

ExternalizableLite, PortableObject, InvocableMap.EntryProcessor, java.io.Serializable

public class ConditionalPutAll

extends AbstractProcessor

implements ExternalizableLite, PortableObject

ConditionalPutAll is an EntryProcessor that performs a Entry.setValue operation for multiple entries that satisfy the specified condition.

Consider such methods of the ConcurrentMap interface as replace(key, value) and putIfAbsent(key, value). While the regular put(key, value) method has the "multi-put" flavor putAll(map), there are no analogous "bulk" operations for those ConcurrentMap methods. The ConditionalPutAll processor provides the corresponding functionality when used in conjunction with the invokeAll(keys, processor) API. For example, the replaceAll(map) method could be implemented as:

   filter = PresentFilter.INSTANCE;
   cache.invokeAll(map.keySet(), new ConditionalPutAll(filter, map));
 

and the putAllIfAbsent(map) could be done by inverting the filter:

   filter = new NotFilter(PresentFilter.INSTANCE);
 

Obviously, using more specific, fine-tuned filters may provide additional flexibility and efficiency allowing the multi-put operations to be performed conditionally on values of specific attributes (or even calculations) instead of a simple existence check.

Since:

Coherence 3.2

Author:

gg 2006.04.28

Field Summary

protected Filter	m_filter The underlying filter.
protected java.util.Map	m_map Specifies the map of new values.

Constructor Summary

ConditionalPutAll()
Default constructor (necessary for the ExternalizableLite interface).

ConditionalPutAll(Filter filter, java.util.Map map)
Construct a ConditionalPutAll processor that updates an entry with a new value if and only if the filter applied to the entry evaluates to true.

Method Summary

boolean	equals(java.lang.Object o) Compare the ConditionalPutAll with another object to determine equality.
int	hashCode() Determine a hash value for the ConditionalPutAll object according to the general Object.hashCode() contract.
java.lang.Object	process(InvocableMap.Entry entry) Process a Map.Entry object.
java.util.Map	processAll(java.util.Set setEntries) Process a Set of InvocableMap.Entry objects.
void	readExternal(java.io.DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
java.lang.String	toString() Return a human-readable description for this ConditionalPutAll.
void	writeExternal(java.io.DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Field Detail

m_filter

protected Filter m_filter

The underlying filter.

m_map

protected java.util.Map m_map

Specifies the map of new values.

Constructor Detail

ConditionalPutAll

public ConditionalPutAll()

Default constructor (necessary for the ExternalizableLite interface).

ConditionalPutAll

public ConditionalPutAll(Filter filter,
                         java.util.Map map)

Construct a ConditionalPutAll processor that updates an entry with a new value if and only if the filter applied to the entry evaluates to true. The new value is extracted from the specified map based on the entry's key.

Parameters:

filter - the filter to evaluate all supplied entries

map - a map of values to update entries with

Method Detail

process

public java.lang.Object process(InvocableMap.Entry entry)

Process a Map.Entry object.

Specified by:

process in interface InvocableMap.EntryProcessor

Parameters:

entry - the Entry to process Note: if this method throws an exception, all modifications to the supplied entry or any other entries retrieved via the BackingMapContext.getBackingMapEntry(java.lang.Object) API will be rolled back leaving all underlying values unchanged.

Returns:

the result of the processing, if any

processAll

public java.util.Map processAll(java.util.Set setEntries)

Process a Set of InvocableMap.Entry objects. This method is semantically equivalent to:

   Map mapResults = new ListMap();
   for (Iterator iter = setEntries.iterator(); iter.hasNext(); )
       {
       Entry entry = (Entry) iter.next();
       mapResults.put(entry.getKey(), process(entry));
       }
   return mapResults;
 

Note: if processAll() call throws an exception, only the entries that were removed from the setEntries would be considered successfully processed and the corresponding changes made to the underlying Map; changes made to the remaining entries or any other entries obtained from BackingMapContext.getBackingMapEntry(java.lang.Object) will not be processed.

Specified by:

processAll in interface InvocableMap.EntryProcessor

Overrides:

processAll in class AbstractProcessor

Parameters:

setEntries - a Set of InvocableMap.Entry objects to process

Returns:

a Map containing the results of the processing, up to one entry for each InvocableMap.Entry that was processed, keyed by the keys of the Map that were processed, with a corresponding value being the result of the processing for each key

equals

public boolean equals(java.lang.Object o)

Compare the ConditionalPutAll with another object to determine equality.

Returns:

true iff this ConditionalPutAll and the passed object are equivalent ConditionalPutAll

hashCode

public int hashCode()

Determine a hash value for the ConditionalPutAll object according to the general Object.hashCode() contract.

Returns:

an integer hash value for this ConditionalPutAll object

toString

public java.lang.String toString()

Return a human-readable description for this ConditionalPutAll.

Returns:

a String description of the ConditionalPutAll

readExternal

public void readExternal(java.io.DataInput in)
                  throws java.io.IOException

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

java.io.IOException - if an I/O exception occurs

java.io.NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(java.io.DataOutput out)
                   throws java.io.IOException

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

java.io.IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws java.io.IOException

Restore the contents of a user type instance by reading its state using the specified PofReader object.

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

java.io.IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws java.io.IOException

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

java.io.IOException - if an I/O error occurs

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