org.jbpm.jpdl.el.impl.ConditionalExpression Maven / Gradle / Ivy
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* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
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* Represents a conditional expression. I've decided not to produce an
* abstract base "TernaryOperatorExpression" class since (a) future ternary
* operators are unlikely and (b) it's not clear that there would be a
* meaningful way to abstract them. (For instance, would they all be right-
* associative? Would they all have two fixed operator symbols?)
*
* @author Shawn Bayern
**/
public class ConditionalExpression
extends Expression
{
//-------------------------------------
// Properties
//-------------------------------------
// property condition
Expression mCondition;
public Expression getCondition ()
{ return mCondition; }
public void setCondition (Expression pCondition)
{ mCondition = pCondition; }
//-------------------------------------
// property trueBranch
Expression mTrueBranch;
public Expression getTrueBranch ()
{ return mTrueBranch; }
public void setTrueBranch (Expression pTrueBranch)
{ mTrueBranch = pTrueBranch; }
//-------------------------------------
// property falseBranch
Expression mFalseBranch;
public Expression getFalseBranch ()
{ return mFalseBranch; }
public void setFalseBranch (Expression pFalseBranch)
{ mFalseBranch = pFalseBranch; }
//-------------------------------------
/**
*
* Constructor
**/
public ConditionalExpression (Expression pCondition,
Expression pTrueBranch,
Expression pFalseBranch)
{
mCondition = pCondition;
mTrueBranch = pTrueBranch;
mFalseBranch = pFalseBranch;
}
//-------------------------------------
// Expression methods
//-------------------------------------
/**
*
* Returns the expression in the expression language syntax
**/
public String getExpressionString ()
{
return
"( " + mCondition.getExpressionString() + " ? " +
mTrueBranch.getExpressionString() + " : " +
mFalseBranch.getExpressionString() + " )";
}
//-------------------------------------
/**
*
* Evaluates the conditional expression and returns the literal result
**/
public Object evaluate (VariableResolver vr,
FunctionMapper f,
Logger l)
throws ELException
{
// first, evaluate the condition (and coerce the result to a boolean value)
boolean condition =
Coercions.coerceToBoolean(
mCondition.evaluate(vr, f, l), l).booleanValue();
// then, use this boolean to branch appropriately
if (condition)
return mTrueBranch.evaluate(vr, f, l);
else
return mFalseBranch.evaluate(vr, f, l);
}
//-------------------------------------
}