org.apache.openjpa.kernel.exps
Class IsEmptyExpression

java.lang.Object
  extended by org.apache.openjpa.kernel.exps.Exp
      extended by org.apache.openjpa.kernel.exps.IsEmptyExpression
All Implemented Interfaces:
Serializable, Expression

 class IsEmptyExpression
extends Exp

Expression to test for an empty Collection.

Author:
Abe White

Constructor Summary
IsEmptyExpression(Val val)
          Constructor.
 
Method Summary
 void acceptVisit(ExpressionVisitor visitor)
          Accept a visit from a tree visitor.
protected  boolean eval(Collection candidates, StoreContext ctx, Object[] params)
          Evaluate the expression for the given group.
protected  boolean eval(Object candidate, Object orig, StoreContext ctx, Object[] params)
          Evaluate the expression for the given context candidate and original candidate.
 
Methods inherited from class org.apache.openjpa.kernel.exps.Exp
evaluate, evaluate
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

IsEmptyExpression

public IsEmptyExpression(Val val)
Constructor. Provide collection/map value to test.

Method Detail

eval

protected boolean eval(Object candidate,
                       Object orig,
                       StoreContext ctx,
                       Object[] params)
Description copied from class: Exp
Evaluate the expression for the given context candidate and original candidate.

Overrides:
eval in class Exp

eval

protected boolean eval(Collection candidates,
                       StoreContext ctx,
                       Object[] params)
Description copied from class: Exp
Evaluate the expression for the given group.

Overrides:
eval in class Exp

acceptVisit

public void acceptVisit(ExpressionVisitor visitor)
Description copied from interface: Expression
Accept a visit from a tree visitor.

Specified by:
acceptVisit in interface Expression
Overrides:
acceptVisit in class Exp


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