net.sf.jec.namedop
Class GroupByOperator

java.lang.Object
  net.sf.jec.Operator
      net.sf.jec.namedop.GroupOperator
          net.sf.jec.namedop.GroupByOperator

public class GroupByOperator

extends GroupOperator

GroupByOperator returns a Map containing keyed groups of elements. If the context object is a collection, the collection will be divided into groups and keyed in the Map. If the context object is a Map, the operation will be recursive on each map entry, so it is possible to group a group.

Author:

mballesteros

Field Summary

Fields inherited from class net.sf.jec.Operator

argOps, nestedOp, showFunctionString

Constructor Summary

GroupByOperator()
Creates a new SumOperator

Method Summary

protected java.lang.Object	directMap(java.lang.Object rootCtx, java.lang.Object ctx) Returns the associated value to the given context and root context
java.lang.String	toExpressionString() Returns an expression String representation for this operator
java.lang.String	toFunctionString() Returns a function representation String for this operator

Methods inherited from class net.sf.jec.namedop.GroupOperator

applyToGroup

Methods inherited from class net.sf.jec.Operator

apply, setArgumentOperators, setNestedOperator, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GroupByOperator

public GroupByOperator()

Creates a new SumOperator

Method Detail

toFunctionString

public java.lang.String toFunctionString()

Returns a function representation String for this operator

Specified by:

toFunctionString in class Operator

toExpressionString

public java.lang.String toExpressionString()

Returns an expression String representation for this operator

Specified by:

toExpressionString in class Operator

directMap

protected java.lang.Object directMap(java.lang.Object rootCtx,
                                     java.lang.Object ctx)
                              throws EvaluationException

Returns the associated value to the given context and root context

Specified by:

directMap in class Operator

Parameters:

rootCtx - The root context, needed for operators that require expression evaluation from root point. Example: Indexer operators

ctx - The current context where the operator will work over

Throws:

EvaluationException