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com.tangosol.util.processor
Class UpdaterProcessor

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

All Implemented Interfaces:

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

public class UpdaterProcessor

extends AbstractProcessor

implements ExternalizableLite, PortableObject

UpdaterProcessor is an EntryProcessor implementations that updates an attribute of an object cached in an InvocableMap. A common usage pattern is:

   cache.invoke(oKey, new UpdaterProcessor(updater, oValue));
 

which is functionally equivalent to the following operation:

   Object oTarget = cache.get(oKey);
   updater.update(oTarget, oValue);
   cache.put(oKey, oTarget);
 

The major difference is that for clustered caches using the UpdaterProcessor allows avoiding explicit concurrency control and could significantly reduce the amount of network traffic.

Author:

gg 2006.07.25

Field Summary

protected java.lang.Object	m_oValue A value to update the entry's value with.
protected ValueUpdater	m_updater The underlying ValueUpdater.

Constructor Summary

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

UpdaterProcessor(java.lang.String sMethod, java.lang.Object oValue)
Construct an UpdaterProcessor for a given method name.

UpdaterProcessor(ValueUpdater updater, java.lang.Object oValue)
Construct an UpdaterProcessor based on the specified ValueUpdater.

Method Summary

boolean	equals(java.lang.Object o) Compare the UpdaterProcessor with another object to determine equality.
int	hashCode() Determine a hash value for the UpdaterProcessor object according to the general Object.hashCode() contract.
java.lang.Object	process(InvocableMap.Entry entry) Process a Map.Entry object.
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 UpdaterProcessor.
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.

Methods inherited from class com.tangosol.util.processor.AbstractProcessor

processAll

Field Detail

m_updater

protected ValueUpdater m_updater

The underlying ValueUpdater.

m_oValue

protected java.lang.Object m_oValue

A value to update the entry's value with.

Constructor Detail

UpdaterProcessor

public UpdaterProcessor()

Default constructor (necessary for the ExternalizableLite interface).

UpdaterProcessor

public UpdaterProcessor(ValueUpdater updater,
                        java.lang.Object oValue)

Construct an UpdaterProcessor based on the specified ValueUpdater.

Parameters:

updater - a ValueUpdater object; passing null will simpy replace the entry's value with the specified one instead of updating it

oValue - the value to update the target entry with

UpdaterProcessor

public UpdaterProcessor(java.lang.String sMethod,
                        java.lang.Object oValue)

Construct an UpdaterProcessor for a given method name. The method must have a single parameter of a Java type compatible with the specified value type.

Parameters:

sMethod - a method name to make a ReflectionUpdater for; this parameter can also be a dot-delimited sequence of method names which would result in using a CompositeUpdater

oValue - the value to update the target entry 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

equals

public boolean equals(java.lang.Object o)

Compare the UpdaterProcessor with another object to determine equality.

Returns:

true iff this UpdaterProcessor and the passed object are equivalent UpdaterProcessor

hashCode

public int hashCode()

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

Returns:

an integer hash value for this UpdaterProcessor object

toString

public java.lang.String toString()

Return a human-readable description for this UpdaterProcessor.

Returns:

a String description of the UpdaterProcessor

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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