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
021 * href="http://activemq.apache.org/camel/predicate.html">predicate</a> on the
022 * message exchange to support things like <a
023 * href="http://activemq.apache.org/camel/scripting-languages.html">scripting
024 * languages</a>, <a href="http://activemq.apache.org/camel/xquery.html">XQuery</a>
025 * or <a href="http://activemq.apache.org/camel/sql.html">SQL</a> as well as
026 * any arbitrary Java expression.
027 *
028 * @version $Revision: 630591 $
029 */
030 public interface Predicate<E> {
031
032 /**
033 * Evaluates the predicate on the message exchange and returns true if this
034 * exchange matches the predicate
035 *
036 * @param exchange the message exchange
037 * @return true if the predicate matches
038 */
039 boolean matches(E exchange);
040
041 /**
042 * Allows this predicate to be used nicely in testing to generate a nicely
043 * formatted exception and message if this predicate does not match for the
044 * given exchange.
045 *
046 * @param text the description to use in the exception message
047 * @param exchange the exchange to evaluate the expression on
048 * @throws AssertionError if the predicate does not match
049 */
050 void assertMatches(String text, E exchange) throws AssertionError;
051
052 }