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/**
*
* 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.
*/
package org.apache.qpid.filter;
//
// Based on like named file from r450141 of the Apache ActiveMQ project <http://www.activemq.org/site/home.html>
//
/**
* A filter performing a comparison of two objects
*/
public abstract class LogicExpression extends BinaryExpression implements BooleanExpression
{
public static BooleanExpression createOR(BooleanExpression lvalue, BooleanExpression rvalue)
{
return new OrExpression(lvalue, rvalue);
}
public static BooleanExpression createAND(BooleanExpression lvalue, BooleanExpression rvalue)
{
return new AndExpression(lvalue, rvalue);
}
/**
* @param left
* @param right
*/
public LogicExpression(BooleanExpression left, BooleanExpression right)
{
super(left, right);
}
public abstract Object evaluate(FilterableMessage message);
public boolean matches(FilterableMessage message)
{
Object object = evaluate(message);
return (object != null) && (object == Boolean.TRUE);
}
private static class OrExpression extends LogicExpression
{
public OrExpression(final BooleanExpression lvalue, final BooleanExpression rvalue)
{
super(lvalue, rvalue);
}
public Object evaluate(FilterableMessage message)
{
Boolean lv = (Boolean) getLeft().evaluate(message);
// Can we do an OR shortcut??
if ((lv != null) && lv.booleanValue())
{
return Boolean.TRUE;
}
Boolean rv = (Boolean) getRight().evaluate(message);
return (rv == null) ? null : rv;
}
public String getExpressionSymbol()
{
return "OR";
}
}
private static class AndExpression extends LogicExpression
{
public AndExpression(final BooleanExpression lvalue, final BooleanExpression rvalue)
{
super(lvalue, rvalue);
}
public Object evaluate(FilterableMessage message)
{
Boolean lv = (Boolean) getLeft().evaluate(message);
// Can we do an AND shortcut??
if (lv == null)
{
return null;
}
if (!lv.booleanValue())
{
return Boolean.FALSE;
}
Boolean rv = (Boolean) getRight().evaluate(message);
return (rv == null) ? null : rv;
}
public String getExpressionSymbol()
{
return "AND";
}
}
}
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