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.builder.ExpressionBuilder;
022 import org.apache.camel.language.IllegalSyntaxException;
023 import org.apache.camel.util.ObjectHelper;
024
025 /**
026 * A <a href="http://activemq.apache.org/camel/simple.html">simple language</a>
027 * which maps simple property style notations to access headers and bodies.
028 * Examples of supported expressions are:
029 * <ul>
030 * <li>id to access the inbound message Id</li>
031 * <li>in.body or body to access the inbound body</li>
032 * <li>out.body to access the inbound body</li>
033 * <li>in.header.foo or header.foo to access an inbound header called 'foo'</li>
034 * <li>out.header.foo to access an outbound header called 'foo'</li>
035 * <li>property.foo to access the exchange property called 'foo'</li>
036 * <li>sys.foo to access the system property called 'foo'</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: 698848 $
047 */
048 public class SimpleLanguage extends AbstractSimpleLanguage {
049
050 public static Expression simple(String expression) {
051 SimpleLanguage language = new SimpleLanguage();
052 return language.createExpression(expression);
053 }
054
055 protected Expression<Exchange> 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 }
063
064 // in header expression
065 String remainder = ifStartsWithReturnRemainder("in.header.", expression);
066 if (remainder == null) {
067 remainder = ifStartsWithReturnRemainder("header.", expression);
068 }
069 if (remainder == null) {
070 remainder = ifStartsWithReturnRemainder("headers.", expression);
071 }
072 if (remainder == null) {
073 remainder = ifStartsWithReturnRemainder("in.headers.", expression);
074 }
075 if (remainder != null) {
076 return ExpressionBuilder.headerExpression(remainder);
077 }
078
079 // out header expression
080 remainder = ifStartsWithReturnRemainder("out.header.", expression);
081 if (remainder == null) {
082 remainder = ifStartsWithReturnRemainder("out.headers.", expression);
083 }
084 if (remainder != null) {
085 return ExpressionBuilder.outHeaderExpression(remainder);
086 }
087
088 // property
089 remainder = ifStartsWithReturnRemainder("property.", expression);
090 if (remainder != null) {
091 return ExpressionBuilder.propertyExpression(remainder);
092 }
093
094 // system property
095 remainder = ifStartsWithReturnRemainder("sys.", expression);
096 if (remainder != null) {
097 return ExpressionBuilder.systemProperty(remainder);
098 }
099
100 // date: prefix
101 remainder = ifStartsWithReturnRemainder("date:", expression);
102 if (remainder != null) {
103 String[] parts = remainder.split(":");
104 if (parts.length != 2) {
105 throw new IllegalSyntaxException(this, expression + " ${date:command:pattern} is the correct syntax.");
106 }
107 String command = parts[0];
108 String pattern = parts[1];
109 return ExpressionBuilder.dateExpression(command, pattern);
110 }
111
112 // bean: prefix
113 remainder = ifStartsWithReturnRemainder("bean:", expression);
114 if (remainder != null) {
115 return ExpressionBuilder.beanExpression(remainder);
116 }
117
118 throw new IllegalSyntaxException(this, expression);
119 }
120
121 }