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 }