org.apache.commons.digester.plugins.strategies.FinderFromDfltResource Maven / Gradle / Ivy
/* $Id: FinderFromDfltResource.java 729125 2008-12-23 21:21:07Z rahul $
*
* 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.commons.digester.plugins.strategies;
import java.io.InputStream;
import java.util.Properties;
import org.apache.commons.digester.Digester;
import org.apache.commons.digester.plugins.RuleFinder;
import org.apache.commons.digester.plugins.RuleLoader;
import org.apache.commons.digester.plugins.PluginException;
/**
* A rule-finding algorithm which looks for a resource file in the classpath
* whose name is derived from the plugin class name plus a specified suffix.
*
* If the resource-file is found, then it is expected to define a set of
* Digester rules in xmlrules format.
*
* @since 1.6
*/
public class FinderFromDfltResource extends RuleFinder {
public static String DFLT_RESOURCE_SUFFIX = "RuleInfo.xml";
private String resourceSuffix;
/** See {@link #findLoader}. */
public FinderFromDfltResource() {
this(DFLT_RESOURCE_SUFFIX);
}
/**
* Create a rule-finder which can load an xmlrules file, cache
* the rules away, and later add them as a plugin's custom rules
* when that plugin is referenced.
*
* @param resourceSuffix must be non-null.
*/
public FinderFromDfltResource(String resourceSuffix) {
this.resourceSuffix = resourceSuffix;
}
/**
* If there exists a resource file whose name is equal to the plugin
* class name + the suffix specified in the constructor, then
* load that file, run it through the xmlrules module and return an object
* encapsulating those rules.
*
* If there is no such resource file, then just return null.
*
* The returned object (when non-null) will add the selected rules to
* the digester whenever its addRules method is invoked.
*/
public RuleLoader findLoader(Digester d, Class pluginClass, Properties p)
throws PluginException {
String resourceName =
pluginClass.getName().replace('.', '/')
+ resourceSuffix;
InputStream is =
pluginClass.getClassLoader().getResourceAsStream(
resourceName);
if (is == null) {
// ok, no such resource
return null;
}
return FinderFromResource.loadRules(d, pluginClass, is, resourceName);
}
}