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; 018 019 /** 020 * Evaluates a binary <a href="http://activemq.apache.org/camel/predicate.html">predicate</a> 021 * on the message exchange to support things like 022 * <a href="http://activemq.apache.org/camel/scripting-languages.html">scripting languages</a>, 023 * <a href="http://activemq.apache.org/camel/xquery.html">XQuery</a> 024 * or <a href="http://activemq.apache.org/camel/sql.html">SQL</a> as well 025 * as any arbitrary Java expression. 026 * 027 * @version $Revision: 532316 $ 028 */ 029 public interface Predicate<E> { 030 031 /** 032 * Evaluates the predicate on the message exchange and returns true 033 * if this exchange matches the predicate 034 * 035 * @param exchange the message exchange 036 * @return true if the predicate matches 037 */ 038 boolean matches(E exchange); 039 040 /** 041 * Allows this predicate to be used nicely in testing to generate 042 * a nicely formatted exception and message if this predicate does not 043 * match for the given exchange. 044 * 045 * @param text the description to use in the exception message 046 * @param exchange the exchange to evaluate the expression on 047 * @throws AssertionError if the predicate does not match 048 */ 049 void assertMatches(String text, E exchange) throws AssertionError; 050 051 }