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com.tangosol.coherence.rest.util.aggregator
Class DefaultAggregatorFactory

java.lang.Object
com.tangosol.coherence.rest.util.aggregator.DefaultAggregatorFactory

All Implemented Interfaces:

AggregatorFactory

public class DefaultAggregatorFactory

extends java.lang.Object

implements AggregatorFactory

The default implementation of AggregatorFactory.

This AggregatorFactory implementation is used for aggregators that accept a single ValueExtractor argument in the constructor and require no additional configuration.

Author:

vp 2011.07.07, ic 2011.07.14

Constructor Summary

DefaultAggregatorFactory(java.lang.Class clzAggr)
Construct a DefaultAggregatorFactory instance.

Method Summary

protected InvocableMap.EntryAggregator	createAggregator(ValueExtractor extractor) Create and initialize a new aggregator instance.
InvocableMap.EntryAggregator	getAggregator(java.lang.String[] asArgs) Return an aggregator instantiated by calling an aggregator class constructor.
protected java.lang.reflect.Constructor	getConstructor(java.lang.reflect.Constructor[] aCtors) Search the given constructors for a constructor that accepts a single ValueExtractor parameter.

Constructor Detail

DefaultAggregatorFactory

public DefaultAggregatorFactory(java.lang.Class clzAggr)

Construct a DefaultAggregatorFactory instance.

Parameters:

clzAggr - the aggregator class

Method Detail

getAggregator

public InvocableMap.EntryAggregator getAggregator(java.lang.String[] asArgs)

Return an aggregator instantiated by calling an aggregator class constructor. The invoked constructor is matched using the following rules:

• If the argument array is empty and a constructor that accepts a single ValueExtractor parameter exists, it will be invoked with an IdentityExtractor instance.
• If the argument array is empty and a constructor that accepts a single ValueExtractor parameter does not exists, the default constructor is invoked.
• If the argument array size is 1 and a constructor that accepts a single ValueExtractor parameter exists, it will be invoked with an MVEL-based ValueExtractor implementation.
• If none of the above rules are matched, an exception is thrown.

Specified by:

getAggregator in interface AggregatorFactory

Parameters:

asArgs - aggregator configuration arguments

Returns:

an aggregator instance

Throws:

java.lang.IllegalArgumentException - if an appropriate constructor cannot be found

createAggregator

protected InvocableMap.EntryAggregator createAggregator(ValueExtractor extractor)

Create and initialize a new aggregator instance.

Parameters:

extractor - ValueExtractor to use for a constructor parameter

Returns:

an aggregator instance

getConstructor

protected java.lang.reflect.Constructor getConstructor(java.lang.reflect.Constructor[] aCtors)

Search the given constructors for a constructor that accepts a single ValueExtractor parameter. If found, return the constructor; otherwise return the public default constructor, if available.

Parameters:

aCtors - constructor array

Returns:

constructor that accepts a single ValueExtractor parameter or, if such a constructor is not found, the public default constructor if available

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