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    
021    /**
022     * A helper class for developers wishing to implement an {@link org.apache.camel.Expression}
023     * using Java code with a minimum amount of code to write so that the developer only needs
024     * to implement one of the {@link #evaluate(org.apache.camel.Exchange, Class)} or
025     * {@link #evaluate(org.apache.camel.Exchange)} methods.
026     *
027     * @version 
028     */
029    public abstract class ExpressionAdapter extends ExpressionSupport {
030    
031        protected String assertionFailureMessage(Exchange exchange) {
032            return toString();
033        }
034    
035        public <T> T evaluate(Exchange exchange, Class<T> type) {
036            Object value = evaluate(exchange);
037            return exchange.getContext().getTypeConverter().convertTo(type, exchange, value);
038        }
039    
040    }