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.language.simple; 018 019 import org.apache.camel.Exchange; 020 import org.apache.camel.Expression; 021 import org.apache.camel.Predicate; 022 import org.apache.camel.builder.ExpressionBuilder; 023 import org.apache.camel.builder.PredicateBuilder; 024 import org.apache.camel.language.IllegalSyntaxException; 025 import org.apache.camel.spi.Language; 026 import org.apache.camel.util.ObjectHelper; 027 028 /** 029 * A <a href="http://activemq.apache.org/camel/simple.html>simple language</a> 030 * which maps simple property style notations to acces headers and bodies. 031 * Examples of supported expressions are <p/> 032 * <ul> 033 * <li>in.header.foo or header.foo to access an inbound header called 'foo'</li> 034 * <li>in.body or body to access the inbound body</li> 035 * <li>out.header.foo to access an outbound header called 'foo'</li> 036 * <li>out.body to access the inbound body</li> 037 * <li>property.foo to access the exchange property called 'foo'</li> 038 * <li>sys.foo to access the system property called 'foo'</li> 039 * </ul> 040 * 041 * @version $Revision: $ 042 */ 043 public class SimpleLanguage implements Language { 044 045 public Predicate<Exchange> createPredicate(String expression) { 046 return PredicateBuilder.toPredicate(createExpression(expression)); 047 } 048 049 public Expression<Exchange> createExpression(String expression) { 050 if (ObjectHelper.isEqualToAny(expression, "body", "in.body")) { 051 return ExpressionBuilder.bodyExpression(); 052 } else if (ObjectHelper.equals(expression, "out.body")) { 053 return ExpressionBuilder.outBodyExpression(); 054 } 055 String remainder = ifStartsWithReturnRemainder("in.header.", expression); 056 if (remainder == null) { 057 remainder = ifStartsWithReturnRemainder("header.", expression); 058 } 059 if (remainder != null) { 060 return ExpressionBuilder.headerExpression(remainder); 061 } 062 remainder = ifStartsWithReturnRemainder("out.header.", expression); 063 if (remainder != null) { 064 return ExpressionBuilder.outHeaderExpression(remainder); 065 } 066 remainder = ifStartsWithReturnRemainder("property.", expression); 067 if (remainder != null) { 068 return ExpressionBuilder.propertyExpression(remainder); 069 } 070 remainder = ifStartsWithReturnRemainder("sys.", expression); 071 if (remainder != null) { 072 return ExpressionBuilder.propertyExpression(remainder); 073 } 074 throw new IllegalSyntaxException(this, expression); 075 } 076 077 protected String ifStartsWithReturnRemainder(String prefix, String text) { 078 if (text.startsWith(prefix)) { 079 String remainder = text.substring(prefix.length()); 080 if (remainder.length() > 0) { 081 082 return remainder; 083 } 084 } 085 return null; 086 } 087 }