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 */ 017package org.apache.camel.support; 018 019import 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 */ 029public 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 if (Object.class == type) { 038 // do not use type converter if type is Object (optimize) 039 return (T) value; 040 } 041 return exchange.getContext().getTypeConverter().convertTo(type, exchange, value); 042 } 043 044}