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.Predicate;
021 import org.apache.camel.builder.ExpressionBuilder;
022 import org.apache.camel.support.LanguageSupport;
023 import org.apache.camel.util.ObjectHelper;
024 import org.apache.camel.util.PredicateToExpressionAdapter;
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 extends LanguageSupport {
092
093 // singleton for expressions without a result type
094 private static final SimpleLanguage SIMPLE = new SimpleLanguage();
095
096 protected boolean allowEscape = true;
097
098 /**
099 * Default constructor.
100 */
101 public SimpleLanguage() {
102 }
103
104 public Predicate createPredicate(String expression) {
105 ObjectHelper.notNull(expression, "expression");
106
107 expression = loadResource(expression);
108
109 // support old simple language syntax
110 @SuppressWarnings("deprecation")
111 Predicate answer = SimpleBackwardsCompatibleParser.parsePredicate(expression, allowEscape);
112 if (answer == null) {
113 // use the new parser
114 SimplePredicateParser parser = new SimplePredicateParser(expression, allowEscape);
115 answer = parser.parsePredicate();
116 }
117 return answer;
118 }
119
120 public Expression createExpression(String expression) {
121 ObjectHelper.notNull(expression, "expression");
122
123 expression = loadResource(expression);
124
125 // support old simple language syntax
126 @SuppressWarnings("deprecation")
127 Expression answer = SimpleBackwardsCompatibleParser.parseExpression(expression, allowEscape);
128 if (answer == null) {
129 // use the new parser
130 SimpleExpressionParser parser = new SimpleExpressionParser(expression, allowEscape);
131 answer = parser.parseExpression();
132 }
133 return answer;
134 }
135
136 /**
137 * Creates a new {@link Expression}.
138 * <p/>
139 * <b>Important:</b> If you need to use a predicate (function to return true|false) then use
140 * {@link #predicate(String)} instead.
141 */
142 public static Expression simple(String expression) {
143 return expression(expression);
144 }
145
146 /**
147 * Creates a new {@link Expression} (or {@link Predicate}
148 * if the resultType is a <tt>Boolean</tt>, or <tt>boolean</tt> type).
149 */
150 public static Expression simple(String expression, Class<?> resultType) {
151 SimpleLanguage answer = new SimpleLanguage();
152 if (resultType == Boolean.class || resultType == boolean.class) {
153 // if its a boolean as result then its a predicate
154 Predicate predicate = answer.createPredicate(expression);
155 return PredicateToExpressionAdapter.toExpression(predicate);
156 } else {
157 Expression exp = answer.createExpression(expression);
158 if (resultType != null) {
159 exp = ExpressionBuilder.convertToExpression(exp, resultType);
160 }
161 return exp;
162 }
163 }
164
165 /**
166 * Creates a new {@link Expression}.
167 * <p/>
168 * <b>Important:</b> If you need to use a predicate (function to return true|false) then use
169 * {@link #predicate(String)} instead.
170 */
171 public static Expression expression(String expression) {
172 return SIMPLE.createExpression(expression);
173 }
174
175 /**
176 * Creates a new {@link Predicate}.
177 */
178 public static Predicate predicate(String predicate) {
179 return SIMPLE.createPredicate(predicate);
180 }
181
182 /**
183 * Change the start 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 start tokens is <tt>${</tt> and <tt>$simple{</tt>.
189 *
190 * @param startToken new start token(s) to be used for functions
191 */
192 public static void changeFunctionStartToken(String... startToken) {
193 SimpleTokenizer.changeFunctionStartToken(startToken);
194 }
195
196 /**
197 * Change the end tokens 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 end token is <tt>}</tt>
203 *
204 * @param endToken new end token(s) to be used for functions
205 */
206 public static void changeFunctionEndToken(String... endToken) {
207 SimpleTokenizer.changeFunctionEndToken(endToken);
208 }
209
210 /**
211 * Change the start 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 start tokens is <tt>${</tt> and <tt>$simple{</tt>.
217 *
218 * @param startToken new start token to be used for functions
219 */
220 public void setFunctionStartToken(String startToken) {
221 changeFunctionStartToken(startToken);
222 }
223
224 /**
225 * Change the end token used for functions.
226 * <p/>
227 * This can be used to alter the function tokens to avoid clashes with other
228 * frameworks etc.
229 * <p/>
230 * The default end token is <tt>}</tt>
231 *
232 * @param endToken new end token to be used for functions
233 */
234 public void setFunctionEndToken(String endToken) {
235 changeFunctionEndToken(endToken);
236 }
237 }