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package bboss.org.apache.velocity.runtime.parser.node;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import bboss.org.apache.velocity.context.InternalContextAdapter;
import bboss.org.apache.velocity.exception.MethodInvocationException;
import bboss.org.apache.velocity.runtime.parser.Parser;
import bboss.org.apache.velocity.util.TemplateNumber;
/**
* Handles arg1 == arg2
*
* This operator requires that the LHS and RHS are both of the
* same Class OR both are subclasses of java.lang.Number
*
* @author Will Glass-Husain
* @author Peter Romianowski
* @version $Id: ASTEQNode.java 691048 2008-09-01 20:26:11Z nbubna $
*/
public class ASTEQNode extends SimpleNode
{
/**
* @param id
*/
public ASTEQNode(int id)
{
super(id);
}
/**
* @param p
* @param id
*/
public ASTEQNode(Parser p, int id)
{
super(p, id);
}
/**
* @see bboss.org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(bboss.org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
*/
public Object jjtAccept(ParserVisitor visitor, Object data)
{
return visitor.visit(this, data);
}
/**
* Calculates the value of the logical expression
*
* arg1 == arg2
*
* All class types are supported. Uses equals() to
* determine equivalence. This should work as we represent
* with the types we already support, and anything else that
* implements equals() to mean more than identical references.
*
*
* @param context internal context used to evaluate the LHS and RHS
* @return true if equivalent, false if not equivalent,
* false if not compatible arguments, or false
* if either LHS or RHS is null
* @throws MethodInvocationException
*/
public boolean evaluate(InternalContextAdapter context)
throws MethodInvocationException
{
Object left = jjtGetChild(0).value(context);
Object right = jjtGetChild(1).value(context);
/*
* convert to Number if applicable
*/
if (left instanceof TemplateNumber)
{
left = ( (TemplateNumber) left).getAsNumber();
}
if (right instanceof TemplateNumber)
{
right = ( (TemplateNumber) right).getAsNumber();
}
/*
* If comparing Numbers we do not care about the Class.
*/
if (left instanceof Number && right instanceof Number)
{
return MathUtils.compare( (Number)left, (Number)right) == 0;
}
/**
* if both are not null, then assume that if one class
* is a subclass of the other that we should use the equals operator
*/
if (left != null && right != null &&
(left.getClass().isAssignableFrom(right.getClass()) ||
right.getClass().isAssignableFrom(left.getClass())))
{
return left.equals( right );
}
/*
* Ok, time to compare string values
*/
left = (left == null) ? null : left.toString();
right = (right == null) ? null: right.toString();
if (left == null && right == null)
{
if (log.isDebugEnabled())
{
log.debug("Both right (" + getLiteral(false) + " and left "
+ getLiteral(true) + " sides of '==' operation returned null."
+ "If references, they may not be in the context."
+ getLocation(context));
}
return true;
}
else if (left == null || right == null)
{
if (log.isDebugEnabled())
{
log.debug((left == null ? "Left" : "Right")
+ " side (" + getLiteral(left == null)
+ ") of '==' operation has null value. If it is a "
+ "reference, it may not be in the context or its "
+ "toString() returned null. " + getLocation(context));
}
return false;
}
else
{
return left.equals(right);
}
}
private String getLiteral(boolean left)
{
return jjtGetChild(left ? 0 : 1).literal();
}
/**
* @see bboss.org.apache.velocity.runtime.parser.node.SimpleNode#value(bboss.org.apache.velocity.context.InternalContextAdapter)
*/
public Object value(InternalContextAdapter context)
throws MethodInvocationException
{
return evaluate(context) ? Boolean.TRUE : Boolean.FALSE;
}
}