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 }