rdonkin 2003/10/04 05:29:01
Added: digester/src/java/org/apache/commons/digester/plugins
PluginDeclarationRule.java
Log:
Added plugins module. Submitted by Simon Kitching.
Revision Changes Path
1.1
jakarta-commons/digester/src/java/org/apache/commons/digester/plugins/PluginDeclarationRule.java
Index: PluginDeclarationRule.java
===================================================================
/*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [EMAIL PROTECTED]
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.digester.plugins;
import java.io.File;
import org.apache.commons.digester.Rule;
import org.apache.commons.digester.Digester;
import org.apache.commons.beanutils.MethodUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A Digester rule which allows the user to pre-declare a class which is to
* be referenced later at a plugin point by a PluginCreateRule.
* <p>
* Normally, a PluginDeclarationRule is added to a Digester instance with
* the pattern "{root}/plugin" or "* /plugin" where {root} is the name of
* the root tag in the input document.
*
* @author Simon Kitching
*/
public class PluginDeclarationRule extends Rule {
private static Log log = LogFactory.getLog(PluginDeclarationRule.class);
//------------------- constructors ---------------------------------------
/** constructor */
public PluginDeclarationRule() {
super();
}
//------------------- methods --------------------------------------------
/**
* Invoked upon reading a tag defining a plugin declaration. The tag
* must have the following mandatory attributes:
* <ul>
* <li> id </li>
* <li> class </li>
* </ul>
*
[EMAIL PROTECTED] namespace The xml namespace in which the xml element which
* triggered this rule resides.
[EMAIL PROTECTED] name The name of the xml element which triggered this rule.
[EMAIL PROTECTED] attributes The set of attributes on the xml element which
* triggered this rule.
[EMAIL PROTECTED] java.lang.Exception
*/
public void begin(
String namespace,
String name,
org.xml.sax.Attributes attributes)
throws java.lang.Exception {
String id = attributes.getValue("id");
String pluginClassName = attributes.getValue("class");
String ruleMethodName = attributes.getValue("method");
String ruleClassName = attributes.getValue("ruleclass");
String ruleResource = attributes.getValue("resource");
String ruleFile = attributes.getValue("file");
String autoSetPropertiesStr = attributes.getValue("setprops");
if (log.isDebugEnabled()) {
log.debug(
"mapping id [" + id + "] -> [" + pluginClassName + "]");
}
if (id == null) {
throw new ClassNotFoundException(
"mandatory attribute id not present on tag"
+ " <" + name + ">");
}
if (pluginClassName == null) {
throw new ClassNotFoundException(
"mandatory attribute class not present on tag"
+ " <" + name + ">");
}
Declaration newDecl = new Declaration(pluginClassName);
newDecl.setId(id);
if (ruleMethodName != null) {
newDecl.setRuleMethod(ruleMethodName);
}
if (ruleClassName != null) {
Class ruleClass;
try {
ruleClass = digester.getClassLoader().loadClass(ruleClassName);
}
catch(ClassNotFoundException cnfe) {
throw new ClassNotFoundException(
"Rule class [" + ruleClassName + "] not found.");
}
newDecl.setRuleClass(ruleClass);
}
if (ruleResource != null) {
newDecl.setRuleResource(ruleResource);
}
if (ruleFile != null) {
newDecl.setRuleFile(new File(ruleFile));
}
if (autoSetPropertiesStr != null) {
newDecl.setAutoSetProperties(
Boolean.valueOf(autoSetPropertiesStr).booleanValue());
}
newDecl.init(digester);
PluginRules rc = (PluginRules) digester.getRules();
PluginManager pm = rc.getPluginManager();
Declaration oldDecl = pm.getDeclarationById(id);
if (oldDecl != null) {
if (oldDecl.isEquivalent(newDecl)) {
// this is a redeclaration of the same plugin mapping.
// this could happen when using xml Entities to include
// external files into the main config file, or to include
// the same external file at multiple locations within a
// parent document. if the declaration is identical,
// then we just ignore it.
log.debug("plugin redeclaration is identical: ignoring");
return;
} else {
throw new Exception("Plugin id [" + id + "] is not unique");
}
}
// check whether this class has already been mapped to a different
// name. It might be nice someday to allow this but lets keep it
// simple for now.
if (pm.getDeclarationByClass(pluginClassName) != null) {
throw new Exception(
"Plugin id [" + id + "] maps to class [" + pluginClassName + "]"
+ " which has already been mapped by some other id.");
}
pm.addDeclaration(newDecl);
}
}
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
