001 /** 002 * 003 * Licensed to the Apache Software Foundation (ASF) under one or more 004 * contributor license agreements. See the NOTICE file distributed with 005 * this work for additional information regarding copyright ownership. 006 * The ASF licenses this file to You under the Apache License, Version 2.0 007 * (the "License"); you may not use this file except in compliance with 008 * the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 package org.apache.camel.util; 019 020 import org.apache.camel.Exchange; 021 import org.apache.camel.Expression; 022 023 /** 024 * A collection of helper methods for working with expressions. 025 * 026 * @version $Revision: 1.1 $ 027 */ 028 public class ExpressionHelper { 029 030 /** 031 * Evaluates the given expression on the exchange as a String value 032 * 033 * @param expression the expression to evaluate 034 * @param exchange the exchange to use to evaluate the expression 035 * @return the result of the evaluation as a string. 036 */ 037 public static <E extends Exchange> String evaluateAsString(Expression<E> expression, E exchange) { 038 return evaluateAsType(expression, exchange, String.class); 039 } 040 041 /** 042 * Evaluates the given expression on the exchange, converting the result to the given type 043 * 044 * @param expression the expression to evaluate 045 * @param exchange the exchange to use to evaluate the expression 046 * @param resultType the type of the result that is required 047 * @return the result of the evaluation as the specified type. 048 */ 049 public static <T, E extends Exchange> T evaluateAsType(Expression<E> expression, E exchange, Class<T> resultType) { 050 Object value = expression.evaluate(exchange); 051 return exchange.getContext().getTypeConverter().convertTo(resultType, value); 052 } 053 }