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.support;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Expression;
021    import org.apache.camel.Predicate;
022    import org.apache.camel.util.ObjectHelper;
023    
024    /**
025     * A useful base class for {@link Predicate} and {@link Expression} implementations
026     *
027     * @version 
028     */
029    public abstract class ExpressionSupport implements Expression, Predicate {
030    
031        public boolean matches(Exchange exchange) {
032            Object value = evaluate(exchange, Object.class);
033            return ObjectHelper.evaluateValuePredicate(value);
034        }
035    
036        public Object evaluate(Exchange exchange) {
037            return evaluate(exchange, Object.class);
038        }
039    
040        public void assertMatches(String text, Exchange exchange) {
041            if (!matches(exchange)) {
042                throw new AssertionError(text + " " + assertionFailureMessage(exchange) + " for exchange: " + exchange);
043            }
044        }
045    
046        protected abstract String assertionFailureMessage(Exchange exchange);
047    }