Package 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 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 Details

    • DefaultAggregatorFactory

      public DefaultAggregatorFactory(Class clzAggr)
      Construct a DefaultAggregatorFactory instance.
      Parameters:
      clzAggr - the aggregator class

  • Method Details

    • getAggregator

      public InvocableMap.EntryAggregator getAggregator(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:
      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 Constructor getConstructor(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