/* $Id: FinderFromDfltMethod.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.util.Properties;
import java.lang.reflect.Method;
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 method with a specific name
* on the plugin class.
*
* @since 1.6
*/
public class FinderFromDfltMethod extends RuleFinder {
public static String DFLT_METHOD_NAME = "addRules";
private String methodName;
/** See {@link #findLoader}. */
public FinderFromDfltMethod() {
this(DFLT_METHOD_NAME);
}
/**
* Create a rule-finder which invokes a specific method on the plugin
* class whenever dynamic rules for a plugin need to be loaded. See the
* findRules method for more info.
*
* @param methodName must be non-null.
*/
public FinderFromDfltMethod(String methodName) {
this.methodName = methodName;
}
/**
* If there exists on the plugin class a method with name matching the
* constructor's methodName value then locate the appropriate Method on
* the plugin class and return an object encapsulating that info.
* <p>
* If there is no matching method then just return null.
* <p>
* The returned object (when non-null) will invoke the target method
* on the plugin class whenever its addRules method is invoked. The
* target method is expected to have the following prototype:
* <code> public static void xxxxx(Digester d, String patternPrefix); </code>
*/
public RuleLoader findLoader(Digester d, Class<?> pluginClass, Properties p)
throws PluginException {
Method rulesMethod = LoaderFromClass.locateMethod(pluginClass, methodName);
if (rulesMethod == null) {
return null;
}
return new LoaderFromClass(pluginClass, rulesMethod);
}
}
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