Oracle® Coherence Java API Reference
v3.5

E14977-01

com.tangosol.util.aggregator
Class Count

java.lang.Object
  extended by com.tangosol.util.Base
      extended by com.tangosol.util.aggregator.Count
All Implemented Interfaces:
ExternalizableLite, PortableObject, InvocableMap.EntryAggregator, InvocableMap.ParallelAwareAggregator, java.io.Serializable

public class Count
extends Base
implements InvocableMap.ParallelAwareAggregator, ExternalizableLite, PortableObject

Calculates a number of values in an entry set.

Since:
Coherence 3.1
Author:
gg 2005.09.05

Constructor Summary
Count()
          Default constructor (necessary for the ExternalizableLite interface).
 
Method Summary
 java.lang.Object aggregate(java.util.Set setEntries)
          Process a set of InvocableMap.Entry objects in order to produce an aggregated result.
 java.lang.Object aggregateResults(java.util.Collection collResults)
          Aggregate the results of the parallel aggregations.
 InvocableMap.EntryAggregator getParallelAggregator()
          Get an aggregator that can take the place of this aggregator in situations in which the InvocableMap can aggregate in parallel.
 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.
 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.
 

Constructor Detail

Count

public Count()
Default constructor (necessary for the ExternalizableLite interface).

Method Detail

aggregate

public java.lang.Object aggregate(java.util.Set setEntries)
Process a set of InvocableMap.Entry objects in order to produce an aggregated result.

Specified by:
aggregate in interface InvocableMap.EntryAggregator
Parameters:
setEntries - a Set of read-only InvocableMap.Entry objects to aggregate
Returns:
the aggregated result from processing the entries

getParallelAggregator

public InvocableMap.EntryAggregator getParallelAggregator()
Get an aggregator that can take the place of this aggregator in situations in which the InvocableMap can aggregate in parallel.

Specified by:
getParallelAggregator in interface InvocableMap.ParallelAwareAggregator
Returns:
the aggregator that will be run in parallel

aggregateResults

public java.lang.Object aggregateResults(java.util.Collection collResults)
Aggregate the results of the parallel aggregations.

Specified by:
aggregateResults in interface InvocableMap.ParallelAwareAggregator
Parameters:
collResults - the parallel aggregation results
Returns:
the aggregation of the parallel aggregation results

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

Oracle® Coherence Java API Reference
v3.5

E14977-01

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