/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.camel.language.simple;
import org.apache.camel.Expression;
import org.apache.camel.Predicate;
import org.apache.camel.builder.ExpressionBuilder;
import org.apache.camel.support.LanguageSupport;
import org.apache.camel.util.ObjectHelper;
import org.apache.camel.util.PredicateToExpressionAdapter;
/**
* A <a href="http://camel.apache.org/simple.html">simple language</a>
* which maps simple property style notations to access headers and bodies.
* Examples of supported expressions are:
* <ul>
* <li>exchangeId to access the exchange id</li>
* <li>id to access the inbound message id</li>
* <li>in.body or body to access the inbound body</li>
* <li>in.body.OGNL or body.OGNL to access the inbound body using an OGNL expression</li>
* <li>mandatoryBodyAs(<classname>) to convert the in body to the given type, will throw exception if not possible to convert</li>
* <li>bodyAs(<classname>) to convert the in body to the given type, will return null if not possible to convert</li>
* <li>headerAs(<key>, <classname>) to convert the in header to the given type, will return null if not possible to convert</li>
* <li>out.body to access the inbound body</li>
* <li>in.header.foo or header.foo to access an inbound header called 'foo'</li>
* <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>
* <li>in.header.foo.OGNL or header.OGNL to access an inbound header called 'foo' using an OGNL expression</li>
* <li>out.header.foo to access an outbound header called 'foo'</li>
* <li>property.foo to access the exchange property called 'foo'</li>
* <li>property.foo.OGNL to access the exchange property called 'foo' using an OGNL expression</li>
* <li>sys.foo to access the system property called 'foo'</li>
* <li>sysenv.foo to access the system environment called 'foo'</li>
* <li>exception.messsage to access the exception message</li>
* <li>threadName to access the current thread name</li>
* <li>date:<command> evaluates to a Date object
* Supported commands are: <tt>now</tt> for current timestamp,
* <tt>in.header.xxx</tt> or <tt>header.xxx</tt> to use the Date object in the in header.
* <tt>out.header.xxx</tt> to use the Date object in the out header.
* <tt>file</tt> for the last modified timestamp of the file (available with a File consumer).
* Command accepts offsets such as: <tt>now-24h</tt> or <tt>in.header.xxx+1h</tt> or even <tt>now+1h30m-100</tt>.
* </li>
* <li>date:<command>:<pattern> for date formatting using {@link java.text.SimpleDateFormat} patterns</li>
* <li>date-with-timezone:<command>:<timezone>:<pattern> for date formatting using {@link java.text.SimpleDateFormat} timezones and patterns</li>
* <li>bean:<bean expression> to invoke a bean using the
* {@link org.apache.camel.language.bean.BeanLanguage BeanLanguage}</li>
* <li>properties:<[locations]>:<key> for using property placeholders using the
* {@link org.apache.camel.component.properties.PropertiesComponent}.
* The locations parameter is optional and you can enter multiple locations separated with comma.
* </li>
* </ul>
* <p/>
* The simple language supports OGNL notation when accessing either body or header.
* <p/>
* The simple language now also includes file language out of the box which means the following expression is also
* supported:
* <ul>
* <li><tt>file:name</tt> to access the file name (is relative, see note below))</li>
* <li><tt>file:name.noext</tt> to access the file name with no extension</li>
* <li><tt>file:name.ext</tt> to access the file extension</li>
* <li><tt>file:ext</tt> to access the file extension</li>
* <li><tt>file:onlyname</tt> to access the file name (no paths)</li>
* <li><tt>file:onlyname.noext</tt> to access the file name (no paths) with no extension </li>
* <li><tt>file:parent</tt> to access the parent file name</li>
* <li><tt>file:path</tt> to access the file path name</li>
* <li><tt>file:absolute</tt> is the file regarded as absolute or relative</li>
* <li><tt>file:absolute.path</tt> to access the absolute file path name</li>
* <li><tt>file:length</tt> to access the file length as a Long type</li>
* <li><tt>file:size</tt> to access the file length as a Long type</li>
* <li><tt>file:modified</tt> to access the file last modified as a Date type</li>
* </ul>
* The <b>relative</b> file is the filename with the starting directory clipped, as opposed to <b>path</b> that will
* return the full path including the starting directory.
* <br/>
* The <b>only</b> file is the filename only with all paths clipped.
*
*/
public class SimpleLanguage extends LanguageSupport {
// singleton for expressions without a result type
private static final SimpleLanguage SIMPLE = new SimpleLanguage();
protected boolean allowEscape = true;
/**
* Default constructor.
*/
public SimpleLanguage() {
}
public Predicate createPredicate(String expression) {
ObjectHelper.notNull(expression, "expression");
expression = loadResource(expression);
// support old simple language syntax
@SuppressWarnings("deprecation")
Predicate answer = SimpleBackwardsCompatibleParser.parsePredicate(expression, allowEscape);
if (answer == null) {
// use the new parser
SimplePredicateParser parser = new SimplePredicateParser(expression, allowEscape);
answer = parser.parsePredicate();
}
return answer;
}
public Expression createExpression(String expression) {
ObjectHelper.notNull(expression, "expression");
expression = loadResource(expression);
// support old simple language syntax
@SuppressWarnings("deprecation")
Expression answer = SimpleBackwardsCompatibleParser.parseExpression(expression, allowEscape);
if (answer == null) {
// use the new parser
SimpleExpressionParser parser = new SimpleExpressionParser(expression, allowEscape);
answer = parser.parseExpression();
}
return answer;
}
/**
* Creates a new {@link Expression}.
* <p/>
* <b>Important:</b> If you need to use a predicate (function to return true|false) then use
* {@link #predicate(String)} instead.
*/
public static Expression simple(String expression) {
return expression(expression);
}
/**
* Creates a new {@link Expression} (or {@link Predicate}
* if the resultType is a <tt>Boolean</tt>, or <tt>boolean</tt> type).
*/
public static Expression simple(String expression, Class<?> resultType) {
return new SimpleLanguage().createExpression(expression, resultType);
}
public Expression createExpression(String expression, Class<?> resultType) {
if (resultType == Boolean.class || resultType == boolean.class) {
// if its a boolean as result then its a predicate
Predicate predicate = createPredicate(expression);
return PredicateToExpressionAdapter.toExpression(predicate);
} else {
Expression exp = createExpression(expression);
if (resultType != null) {
exp = ExpressionBuilder.convertToExpression(exp, resultType);
}
return exp;
}
}
/**
* Creates a new {@link Expression}.
* <p/>
* <b>Important:</b> If you need to use a predicate (function to return true|false) then use
* {@link #predicate(String)} instead.
*/
public static Expression expression(String expression) {
return SIMPLE.createExpression(expression);
}
/**
* Creates a new {@link Predicate}.
*/
public static Predicate predicate(String predicate) {
return SIMPLE.createPredicate(predicate);
}
/**
* Does the expression include a simple function.
*
* @param expression the expression
* @return <tt>true</tt> if one or more simple function is included in the expression
*/
public static boolean hasSimpleFunction(String expression) {
return SimpleTokenizer.hasFunctionStartToken(expression);
}
/**
* Change the start tokens used for functions.
* <p/>
* This can be used to alter the function tokens to avoid clashes with other
* frameworks etc.
* <p/>
* The default start tokens is <tt>${</tt> and <tt>$simple{</tt>.
*
* @param startToken new start token(s) to be used for functions
*/
public static void changeFunctionStartToken(String... startToken) {
SimpleTokenizer.changeFunctionStartToken(startToken);
}
/**
* Change the end tokens used for functions.
* <p/>
* This can be used to alter the function tokens to avoid clashes with other
* frameworks etc.
* <p/>
* The default end token is <tt>}</tt>
*
* @param endToken new end token(s) to be used for functions
*/
public static void changeFunctionEndToken(String... endToken) {
SimpleTokenizer.changeFunctionEndToken(endToken);
}
/**
* Change the start token used for functions.
* <p/>
* This can be used to alter the function tokens to avoid clashes with other
* frameworks etc.
* <p/>
* The default start tokens is <tt>${</tt> and <tt>$simple{</tt>.
*
* @param startToken new start token to be used for functions
*/
public void setFunctionStartToken(String startToken) {
changeFunctionStartToken(startToken);
}
/**
* Change the end token used for functions.
* <p/>
* This can be used to alter the function tokens to avoid clashes with other
* frameworks etc.
* <p/>
* The default end token is <tt>}</tt>
*
* @param endToken new end token to be used for functions
*/
public void setFunctionEndToken(String endToken) {
changeFunctionEndToken(endToken);
}
}