- /* $Id: FinderFromDfltClass.java,v 1.5 2004/05/10 06:34:01 skitching Exp $
- *
- * Copyright 2004 The Apache Software Foundation.
- *
- * Licensed 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 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 a class whose name is derived from the plugin class name.
- *
- * @since 1.6
- */
-
- public class FinderFromDfltClass extends RuleFinder {
- public static String DFLT_RULECLASS_SUFFIX = "RuleInfo";
- public static String DFLT_METHOD_NAME = "addRules";
-
- private String rulesClassSuffix;
- private String methodName;
-
- /** See {@link #findLoader}. */
- public FinderFromDfltClass() {
- this(DFLT_RULECLASS_SUFFIX, DFLT_METHOD_NAME);
- }
-
- /**
- * Create a rule-finder which invokes a method on a class whenever
- * dynamic rules for a plugin need to be loaded. See the findRules
- * method for more info.
- *
- * @param rulesClassSuffix must be non-null.
- * @param methodName may be null.
- */
- public FinderFromDfltClass(String rulesClassSuffix, String methodName) {
- this.rulesClassSuffix = rulesClassSuffix;
- this.methodName = methodName;
- }
-
- /**
- * If there exists a class whose name is the plugin class name + the
- * suffix specified to the constructor, then load that class, locate
- * the appropriate rules-adding method on that class, and return an
- * object encapsulating that info.
- * <p>
- * If there is no such class, then just return null.
- * <p>
- * The returned object (when non-null) will invoke the target method
- * on the selected 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 digester, Class pluginClass, Properties p)
- throws PluginException {
-
- String rulesClassName = pluginClass.getName() + rulesClassSuffix;
-
- Class rulesClass = null;
- try {
- rulesClass = digester.getClassLoader().loadClass(rulesClassName);
- } catch(ClassNotFoundException cnfe) {
- // ok, ignore
- }
-
- if (rulesClass == null) {
- // nope, no rule-info class in the classpath
- return null;
- }
-
- if (methodName == null) {
- methodName = DFLT_METHOD_NAME;
- }
-
- return new LoaderFromClass(rulesClass, methodName);
- }
- }
-