001 /** 002 * 003 * Copyright 2004 Hiram Chirino 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 **/ 018 package org.activemq.filter; 019 020 import javax.jms.JMSException; 021 import javax.jms.Message; 022 023 /** 024 * A filter performing a comparison of two objects 025 * 026 * @version $Revision: 1.1.1.1 $ 027 */ 028 public abstract class LogicExpression extends BinaryExpression implements BooleanExpression { 029 030 public static BooleanExpression createOR(BooleanExpression lvalue, BooleanExpression rvalue) { 031 return new LogicExpression(lvalue, rvalue) { 032 033 public Object evaluate(Message message) throws JMSException { 034 035 Boolean lv = (Boolean) left.evaluate(message); 036 // Can we do an OR shortcut?? 037 if (lv !=null && lv.booleanValue()) { 038 return Boolean.TRUE; 039 } 040 041 Boolean rv = (Boolean) right.evaluate(message); 042 return rv==null ? null : rv; 043 } 044 045 public String getExpressionSymbol() { 046 return "OR"; 047 } 048 }; 049 } 050 051 public static BooleanExpression createAND(BooleanExpression lvalue, BooleanExpression rvalue) { 052 return new LogicExpression(lvalue, rvalue) { 053 054 public Object evaluate(Message message) throws JMSException { 055 056 Boolean lv = (Boolean) left.evaluate(message); 057 058 // Can we do an AND shortcut?? 059 if( lv==null ) 060 return null; 061 if (!lv.booleanValue()) { 062 return Boolean.FALSE; 063 } 064 065 Boolean rv = (Boolean) right.evaluate(message); 066 return rv==null ? null : rv; 067 } 068 069 public String getExpressionSymbol() { 070 return "AND"; 071 } 072 }; 073 } 074 075 /** 076 * @param left 077 * @param right 078 */ 079 public LogicExpression(BooleanExpression left, BooleanExpression right) { 080 super(left, right); 081 } 082 083 abstract public Object evaluate(Message message) throws JMSException; 084 085 086 }