001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. 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 package org.apache.camel.builder; 018 019 import org.apache.camel.BinaryPredicate; 020 import org.apache.camel.Exchange; 021 import org.apache.camel.Expression; 022 import org.apache.camel.Predicate; 023 024 import static org.apache.camel.util.ObjectHelper.notNull; 025 026 /** 027 * A useful base class for {@link Predicate} implementations 028 * 029 * @version $Revision: 1003810 $ 030 */ 031 public abstract class BinaryPredicateSupport implements BinaryPredicate { 032 033 private final Expression left; 034 private final Expression right; 035 private Object lastLeftValue; 036 private Object lastRightValue; 037 038 protected BinaryPredicateSupport(Expression left, Expression right) { 039 notNull(left, "left"); 040 notNull(right, "right"); 041 042 this.left = left; 043 this.right = right; 044 } 045 046 @Override 047 public String toString() { 048 return left + " " + getOperationText() + " " + right; 049 } 050 051 public boolean matches(Exchange exchange) { 052 // must be thread safe and store result in local objects 053 Object leftValue = left.evaluate(exchange, Object.class); 054 Object rightValue = right.evaluate(exchange, Object.class); 055 // remember last result (may not be thread safe) 056 lastRightValue = rightValue; 057 lastLeftValue = leftValue; 058 return matches(exchange, leftValue, rightValue); 059 } 060 061 protected abstract boolean matches(Exchange exchange, Object leftValue, Object rightValue); 062 063 protected abstract String getOperationText(); 064 065 public Expression getRight() { 066 return right; 067 } 068 069 public Expression getLeft() { 070 return left; 071 } 072 073 public String getOperator() { 074 return getOperationText(); 075 } 076 077 public Object getRightValue() { 078 return lastRightValue; 079 } 080 081 public Object getLeftValue() { 082 return lastLeftValue; 083 } 084 }