| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.camel.language.spel; |
| |
| import org.apache.camel.Exchange; |
| import org.apache.camel.ExpressionEvaluationException; |
| import org.apache.camel.impl.ExpressionSupport; |
| import org.apache.camel.spring.SpringCamelContext; |
| import org.springframework.context.ApplicationContext; |
| import org.springframework.context.expression.BeanFactoryResolver; |
| import org.springframework.expression.EvaluationContext; |
| import org.springframework.expression.Expression; |
| import org.springframework.expression.ParserContext; |
| import org.springframework.expression.common.TemplateParserContext; |
| import org.springframework.expression.spel.standard.SpelExpressionParser; |
| import org.springframework.expression.spel.support.StandardEvaluationContext; |
| |
| /** |
| * Class responsible for evaluating <a href="http://static.springsource.org |
| * /spring/docs/current/spring-framework-reference/html/expressions.html"> |
| * Spring Expression Language</a> in the context of Camel. |
| */ |
| public class SpelExpression extends ExpressionSupport { |
| |
| private final String expressionString; |
| private final Class<?> type; |
| |
| // SpelExpressionParser is thread-safe according to the docs |
| private final SpelExpressionParser expressionParser; |
| |
| public SpelExpression(String expressionString, Class<?> type) { |
| this.expressionString = expressionString; |
| this.type = type; |
| this.expressionParser = new SpelExpressionParser(); |
| } |
| |
| public static SpelExpression spel(String expression) { |
| return new SpelExpression(expression, Object.class); |
| } |
| |
| public <T> T evaluate(Exchange exchange, Class<T> tClass) { |
| try { |
| Expression expression = parseExpression(); |
| EvaluationContext evaluationContext = createEvaluationContext(exchange); |
| Object value = expression.getValue(evaluationContext); |
| // Let Camel handle the type conversion |
| return exchange.getContext().getTypeConverter().convertTo(tClass, value); |
| } catch (Exception e) { |
| throw new ExpressionEvaluationException(this, exchange, e); |
| } |
| } |
| |
| private EvaluationContext createEvaluationContext(Exchange exchange) { |
| StandardEvaluationContext evaluationContext = new StandardEvaluationContext(new RootObject(exchange)); |
| if (exchange.getContext() instanceof SpringCamelContext) { |
| // Support references (like @foo) in expressions to beans defined in the Registry/ApplicationContext |
| ApplicationContext applicationContext = ((SpringCamelContext) exchange.getContext()).getApplicationContext(); |
| evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext)); |
| } |
| return evaluationContext; |
| } |
| |
| private Expression parseExpression() { |
| // Support template parsing with #{ } delimiters |
| ParserContext parserContext = new TemplateParserContext(); |
| Expression expression = expressionParser.parseExpression(expressionString, parserContext); |
| return expression; |
| } |
| |
| public Class<?> getType() { |
| return type; |
| } |
| |
| protected String assertionFailureMessage(Exchange exchange) { |
| return expressionString; |
| } |
| |
| @Override |
| public String toString() { |
| return "SpelExpression[" + expressionString + "]"; |
| } |
| } |