package org.apache.commons.digester3.plugins.strategies;

/*
 * 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.
 */

import java.util.Properties;
import java.lang.reflect.Method;

import org.apache.commons.digester3.Digester;
import org.apache.commons.digester3.plugins.PluginException;
import org.apache.commons.digester3.plugins.RuleFinder;
import org.apache.commons.digester3.plugins.RuleLoader;

A rule-finding algorithm which looks for a method with a specific name on the plugin class.
Since:
1.6/**
 * 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
{
    private static final String DFLT_METHOD_NAME = "addRules";

    private final String methodName;

    
See findLoader. /** 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.
Params:
methodName – must be non-null./**
     * 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.

If there is no matching method then just return null.

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:
 public static void xxxxx(Digester d, String patternPrefix); 
Params:
d – The digester instance where locating plugin classes
pluginClass – The plugin Java class
p – The properties object that holds any xml attributes the user may have specified on the plugin
         declaration in order to indicate how to locate the plugin rules.
Throws:
PluginException – if the algorithm finds a source of rules, but there is something invalid
        about that source.
Returns:
a source of digester rules for the specified plugin class./**
     * 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>
     *
     * @param d The digester instance where locating plugin classes
     * @param pluginClass The plugin Java class
     * @param p The properties object that holds any xml attributes the user may have specified on the plugin
     *          declaration in order to indicate how to locate the plugin rules.
     * @return a source of digester rules for the specified plugin class.
     * @throws PluginException if the algorithm finds a source of rules, but there is something invalid
     *         about that source.
     */
    @Override
    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 );
    }

}