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.Expression;
020 import org.apache.camel.ExpressionIllegalSyntaxException;
021 import org.apache.camel.builder.ExpressionBuilder;
022 import org.apache.camel.util.ObjectHelper;
023
024 /**
025 * A <a href="http://camel.apache.org/simple.html">simple language</a>
026 * which maps simple property style notations to access headers and bodies.
027 * Examples of supported expressions are:
028 * <ul>
029 * <li>id to access the inbound message id</li>
030 * <li>in.body or body to access the inbound body</li>
031 * <li>out.body to access the inbound body</li>
032 * <li>in.header.foo or header.foo to access an inbound header called 'foo'</li>
033 * <li>out.header.foo to access an outbound header called 'foo'</li>
034 * <li>property.foo to access the exchange property called 'foo'</li>
035 * <li>sys.foo to access the system property called 'foo'</li>
036 * <li>exception.messsage to access the exception message</li>
037 * <li>date:<command>:<pattern> for date formatting using the {@link java.text.SimpleDateFormat} patterns.
038 * Supported commands are: <tt>now</tt> for current timestamp,
039 * <tt>in.header.xxx</tt> or <tt>header.xxx</tt> to use the Date object in the in header.
040 * <tt>out.header.xxx</tt> to use the Date object in the out header.
041 * </li>
042 * <li>bean:<bean expression> to invoke a bean using the
043 * {@link org.apache.camel.language.bean.BeanLanguage BeanLanguage}</li>
044 * </ul>
045 *
046 * @version $Revision: 752893 $
047 */
048 public class SimpleLanguage extends SimpleLanguageSupport {
049
050 public static Expression simple(String expression) {
051 SimpleLanguage language = new SimpleLanguage();
052 return language.createExpression(expression);
053 }
054
055 protected Expression createSimpleExpression(String expression) {
056 if (ObjectHelper.isEqualToAny(expression, "body", "in.body")) {
057 return ExpressionBuilder.bodyExpression();
058 } else if (ObjectHelper.equal(expression, "out.body")) {
059 return ExpressionBuilder.outBodyExpression();
060 } else if (ObjectHelper.equal(expression, "id")) {
061 return ExpressionBuilder.messageIdExpression();
062 } else if (ObjectHelper.equal(expression, "exception.message")) {
063 return ExpressionBuilder.exchangeExceptionMessageExpression();
064 }
065
066 // in header expression
067 String remainder = ifStartsWithReturnRemainder("in.header.", expression);
068 if (remainder == null) {
069 remainder = ifStartsWithReturnRemainder("header.", expression);
070 }
071 if (remainder == null) {
072 remainder = ifStartsWithReturnRemainder("headers.", expression);
073 }
074 if (remainder == null) {
075 remainder = ifStartsWithReturnRemainder("in.headers.", expression);
076 }
077 if (remainder != null) {
078 return ExpressionBuilder.headerExpression(remainder);
079 }
080
081 // out header expression
082 remainder = ifStartsWithReturnRemainder("out.header.", expression);
083 if (remainder == null) {
084 remainder = ifStartsWithReturnRemainder("out.headers.", expression);
085 }
086 if (remainder != null) {
087 return ExpressionBuilder.outHeaderExpression(remainder);
088 }
089
090 // property
091 remainder = ifStartsWithReturnRemainder("property.", expression);
092 if (remainder != null) {
093 return ExpressionBuilder.propertyExpression(remainder);
094 }
095
096 // system property
097 remainder = ifStartsWithReturnRemainder("sys.", expression);
098 if (remainder != null) {
099 return ExpressionBuilder.systemPropertyExpression(remainder);
100 }
101
102 // date: prefix
103 remainder = ifStartsWithReturnRemainder("date:", expression);
104 if (remainder != null) {
105 String[] parts = remainder.split(":");
106 if (parts.length != 2) {
107 throw new ExpressionIllegalSyntaxException("Valid syntax: ${date:command:pattern} was: " + expression);
108 }
109 String command = parts[0];
110 String pattern = parts[1];
111 return ExpressionBuilder.dateExpression(command, pattern);
112 }
113
114 // bean: prefix
115 remainder = ifStartsWithReturnRemainder("bean:", expression);
116 if (remainder != null) {
117 return ExpressionBuilder.beanExpression(remainder);
118 }
119
120 throw new ExpressionIllegalSyntaxException(expression);
121 }
122
123 public boolean isSingleton() {
124 return true;
125 }
126 }