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.IsSingleton;
021 import org.apache.camel.Predicate;
022 import org.apache.camel.builder.ExpressionBuilder;
023 import org.apache.camel.spi.Language;
024 import org.apache.camel.util.ObjectHelper;
025
026 /**
027 * A <a href="http://camel.apache.org/simple.html">simple language</a>
028 * which maps simple property style notations to access headers and bodies.
029 * Examples of supported expressions are:
030 * <ul>
031 * <li>exchangeId to access the exchange id</li>
032 * <li>id to access the inbound message id</li>
033 * <li>in.body or body to access the inbound body</li>
034 * <li>in.body.OGNL or body.OGNL to access the inbound body using an OGNL expression</li>
035 * <li>mandatoryBodyAs(<classname>) to convert the in body to the given type, will throw exception if not possible to convert</li>
036 * <li>bodyAs(<classname>) to convert the in body to the given type, will return null if not possible to convert</li>
037 * <li>headerAs(<key>, <classname>) to convert the in header to the given type, will return null if not possible to convert</li>
038 * <li>out.body to access the inbound body</li>
039 * <li>in.header.foo or header.foo to access an inbound header called 'foo'</li>
040 * <li>in.header.foo[bar] or header.foo[bar] to access an inbound header called 'foo' as a Map and lookup the map with 'bar' as key</li>
041 * <li>in.header.foo.OGNL or header.OGNL to access an inbound header called 'foo' using an OGNL expression</li>
042 * <li>out.header.foo to access an outbound header called 'foo'</li>
043 * <li>property.foo to access the exchange property called 'foo'</li>
044 * <li>property.foo.OGNL to access the exchange property called 'foo' using an OGNL expression</li>
045 * <li>sys.foo to access the system property called 'foo'</li>
046 * <li>sysenv.foo to access the system environment called 'foo'</li>
047 * <li>exception.messsage to access the exception message</li>
048 * <li>threadName to access the current thread name</li>
049 * <li>date:<command>:<pattern> for date formatting using the {@link java.text.SimpleDateFormat} patterns.
050 * Supported commands are: <tt>now</tt> for current timestamp,
051 * <tt>in.header.xxx</tt> or <tt>header.xxx</tt> to use the Date object in the in header.
052 * <tt>out.header.xxx</tt> to use the Date object in the out header.
053 * </li>
054 * <li>bean:<bean expression> to invoke a bean using the
055 * {@link org.apache.camel.language.bean.BeanLanguage BeanLanguage}</li>
056 * <li>properties:<[locations]>:<key> for using property placeholders using the
057 * {@link org.apache.camel.component.properties.PropertiesComponent}.
058 * The locations parameter is optional and you can enter multiple locations separated with comma.
059 * </li>
060 * </ul>
061 * <p/>
062 * The simple language supports OGNL notation when accessing either body or header.
063 * <p/>
064 * The simple language now also includes file language out of the box which means the following expression is also
065 * supported:
066 * <ul>
067 * <li><tt>file:name</tt> to access the file name (is relative, see note below))</li>
068 * <li><tt>file:name.noext</tt> to access the file name with no extension</li>
069 * <li><tt>file:name.ext</tt> to access the file extension</li>
070 * <li><tt>file:ext</tt> to access the file extension</li>
071 * <li><tt>file:onlyname</tt> to access the file name (no paths)</li>
072 * <li><tt>file:onlyname.noext</tt> to access the file name (no paths) with no extension </li>
073 * <li><tt>file:parent</tt> to access the parent file name</li>
074 * <li><tt>file:path</tt> to access the file path name</li>
075 * <li><tt>file:absolute</tt> is the file regarded as absolute or relative</li>
076 * <li><tt>file:absolute.path</tt> to access the absolute file path name</li>
077 * <li><tt>file:length</tt> to access the file length as a Long type</li>
078 * <li><tt>file:size</tt> to access the file length as a Long type</li>
079 * <li><tt>file:modified</tt> to access the file last modified as a Date type</li>
080 * <li><tt>date:<command>:<pattern></tt> for date formatting using the {@link java.text.SimpleDateFormat} patterns.
081 * Additional Supported commands are: <tt>file</tt> for the last modified timestamp of the file.
082 * All the commands from {@link SimpleLanguage} is also available.
083 * </li>
084 * </ul>
085 * The <b>relative</b> file is the filename with the starting directory clipped, as opposed to <b>path</b> that will
086 * return the full path including the starting directory.
087 * <br/>
088 * The <b>only</b> file is the filename only with all paths clipped.
089 *
090 */
091 public class SimpleLanguage implements Language, IsSingleton {
092
093 // singleton for expressions without a result type
094 private static final SimpleLanguage SIMPLE = new SimpleLanguage();
095
096 protected Class<?> resultType;
097 protected boolean allowEscape = true;
098
099 /**
100 * Default constructor.
101 */
102 public SimpleLanguage() {
103 }
104
105 public Class<?> getResultType() {
106 return resultType;
107 }
108
109 public void setResultType(Class<?> resultType) {
110 this.resultType = resultType;
111 }
112
113 public boolean isAllowEscape() {
114 return allowEscape;
115 }
116
117 public void setAllowEscape(boolean allowEscape) {
118 this.allowEscape = allowEscape;
119 }
120
121 @Override
122 public boolean isSingleton() {
123 // we cannot be singleton as we have state
124 return false;
125 }
126
127 public Predicate createPredicate(String expression) {
128 ObjectHelper.notNull(expression, "expression");
129
130 // support old simple language syntax
131 @SuppressWarnings("deprecation")
132 Predicate answer = SimpleBackwardsCompatibleParser.parsePredicate(expression, allowEscape);
133 if (answer == null) {
134 // use the new parser
135 SimplePredicateParser parser = new SimplePredicateParser(expression, allowEscape);
136 answer = parser.parsePredicate();
137 }
138 return answer;
139 }
140
141 public Expression createExpression(String expression) {
142 ObjectHelper.notNull(expression, "expression");
143
144 // support old simple language syntax
145 @SuppressWarnings("deprecation")
146 Expression answer = SimpleBackwardsCompatibleParser.parseExpression(expression, allowEscape);
147 if (answer == null) {
148 // use the new parser
149 SimpleExpressionParser parser = new SimpleExpressionParser(expression, allowEscape);
150 answer = parser.parseExpression();
151 }
152 if (resultType != null) {
153 answer = ExpressionBuilder.convertToExpression(answer, resultType);
154 }
155 return answer;
156 }
157
158 public static Expression simple(String expression) {
159 return SIMPLE.createExpression(expression);
160 }
161
162 public static Expression simple(String expression, Class<?> resultType) {
163 SimpleLanguage answer = new SimpleLanguage();
164 answer.setResultType(resultType);
165 return answer.createExpression(expression);
166 }
167
168 /**
169 * Change the start tokens used for functions.
170 * <p/>
171 * This can be used to alter the function tokens to avoid clashes with other
172 * frameworks etc.
173 * <p/>
174 * The default start tokens is <tt>${</tt> and <tt>$simple{</tt>.
175 *
176 * @param startToken new start token(s) to be used for functions
177 */
178 public static void changeFunctionStartToken(String... startToken) {
179 SimpleTokenizer.changeFunctionStartToken(startToken);
180 }
181
182 /**
183 * Change the end tokens used for functions.
184 * <p/>
185 * This can be used to alter the function tokens to avoid clashes with other
186 * frameworks etc.
187 * <p/>
188 * The default end token is <tt>}</tt>
189 *
190 * @param endToken new end token(s) to be used for functions
191 */
192 public static void changeFunctionEndToken(String... endToken) {
193 SimpleTokenizer.changeFunctionEndToken(endToken);
194 }
195
196 /**
197 * Change the start token used for functions.
198 * <p/>
199 * This can be used to alter the function tokens to avoid clashes with other
200 * frameworks etc.
201 * <p/>
202 * The default start tokens is <tt>${</tt> and <tt>$simple{</tt>.
203 *
204 * @param startToken new start token to be used for functions
205 */
206 public void setFunctionStartToken(String startToken) {
207 changeFunctionStartToken(startToken);
208 }
209
210 /**
211 * Change the end token used for functions.
212 * <p/>
213 * This can be used to alter the function tokens to avoid clashes with other
214 * frameworks etc.
215 * <p/>
216 * The default end token is <tt>}</tt>
217 *
218 * @param endToken new end token to be used for functions
219 */
220 public void setFunctionEndToken(String endToken) {
221 changeFunctionEndToken(endToken);
222 }
223 }