package org.apache.commons.digester3.plugins;

/*
 * 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 org.apache.commons.logging.Log;
import org.apache.commons.digester3.Digester;

Represents a Class that can be instantiated by a PluginCreateRule, plus info on how to load custom digester rules for
mapping xml into that plugged-in class.
Since:
1.6/**
 * Represents a Class that can be instantiated by a PluginCreateRule, plus info on how to load custom digester rules for
 * mapping xml into that plugged-in class.
 * 
 * @since 1.6
 */
public class Declaration
{

    
The class of the object to be instantiated. /** The class of the object to be instantiated. */
    private Class<?> pluginClass;

    
The name of the class of the object to be instantiated. /** The name of the class of the object to be instantiated. */
    private String pluginClassName;

    
See setId. /** See {@link #setId}. */
    private String id;

    
See setProperties. /** See {@link #setProperties}. */
    private Properties properties = new Properties();

    
See init. /** See {@link #init}. */
    private boolean initialized = false;

    
Class which is responsible for dynamically loading this plugin's rules on demand.
/**
     * Class which is responsible for dynamically loading this plugin's rules on demand.
     */
    private RuleLoader ruleLoader = null;

    // ---------------------- constructors ----------------------------------

    
Constructor.
Params:
pluginClassName – The name of the class of the object to be instantiated (will be load in the init method)/**
     * Constructor.
     *
     * @param pluginClassName The name of the class of the object to be instantiated (will be load in the init method)
     */
    public Declaration( String pluginClassName )
    {
        // We can't load the pluginClass at this time, because we don't
        // have a digester instance yet to load it through. So just
        // save the name away, and we'll load the Class object in the
        // init method.
        this.pluginClassName = pluginClassName;
    }

    
Constructor.
Params:
pluginClass – The class of the object to be instantiated (will be load in the init method)/**
     * Constructor.
     *
     * @param pluginClass The class of the object to be instantiated (will be load in the init method)
     */
    public Declaration( Class<?> pluginClass )
    {
        this.pluginClass = pluginClass;
        this.pluginClassName = pluginClass.getName();
    }

    
Create an instance where a fully-initialised ruleLoader instance is provided by the caller instead of having the
PluginManager "discover" an appropriate one.
Params:
pluginClass – The class of the object to be instantiated (will be load in the init method)
ruleLoader – Class which is responsible for dynamically loading this plugin's rules on demand/**
     * Create an instance where a fully-initialised ruleLoader instance is provided by the caller instead of having the
     * PluginManager "discover" an appropriate one.
     *
     * @param pluginClass The class of the object to be instantiated (will be load in the init method)
     * @param ruleLoader Class which is responsible for dynamically loading this plugin's rules on demand
     */
    public Declaration( Class<?> pluginClass, RuleLoader ruleLoader )
    {
        this.pluginClass = pluginClass;
        this.pluginClassName = pluginClass.getName();
        this.ruleLoader = ruleLoader;
    }

    // ---------------------- properties -----------------------------------

    
The id that the user associated with a particular plugin declaration in the input xml. This id is later used in
the input xml to refer back to the original declaration.

For plugins declared "in-line", the id is null.
Params:
id – The id that the user associated with a particular plugin declaration in the input xml/**
     * The id that the user associated with a particular plugin declaration in the input xml. This id is later used in
     * the input xml to refer back to the original declaration.
     * <p>
     * For plugins declared "in-line", the id is null.
     *
     * @param id The id that the user associated with a particular plugin declaration in the input xml
     */
    public void setId( String id )
    {
        this.id = id;
    }

    
Return the id associated with this declaration. For plugins declared "inline", null will be returned.
Returns:
The id value. May be null./**
     * Return the id associated with this declaration. For plugins declared "inline", null will be returned.
     * 
     * @return The id value. May be null.
     */
    public String getId()
    {
        return id;
    }

    
Copy all (key,value) pairs in the param into the properties member of this object.

The declaration properties cannot be explicit member variables, because the set of useful properties a user can
provide on a declaration depends on what RuleFinder classes are available - and extra RuleFinders can be added by
the user. So here we keep a map of the settings, and let the RuleFinder objects look for whatever properties they
consider significant.

The "id" and "class" properties are treated differently.
Params:
p – The properties have to be copied into the properties member of this object/**
     * Copy all (key,value) pairs in the param into the properties member of this object.
     * <p>
     * The declaration properties cannot be explicit member variables, because the set of useful properties a user can
     * provide on a declaration depends on what RuleFinder classes are available - and extra RuleFinders can be added by
     * the user. So here we keep a map of the settings, and let the RuleFinder objects look for whatever properties they
     * consider significant.
     * <p>
     * The "id" and "class" properties are treated differently.
     *
     * @param p The properties have to be copied into the properties member of this object
     */
    public void setProperties( Properties p )
    {
        properties.putAll( p );
    }

    
Return plugin class associated with this declaration.
Returns:
The pluginClass./**
     * Return plugin class associated with this declaration.
     * 
     * @return The pluginClass.
     */
    public Class<?> getPluginClass()
    {
        return pluginClass;
    }

    // ---------------------- methods -----------------------------------

    
Must be called exactly once, and must be called before any call to the configure method.
Params:
digester – The Digester instance where plugin has to be plugged
pm – The plugin manager reference
Throws:
PluginException – if any error occurs while loading the rules/**
     * Must be called exactly once, and must be called before any call to the configure method.
     *
     * @param digester The Digester instance where plugin has to be plugged
     * @param pm The plugin manager reference
     * @throws PluginException if any error occurs while loading the rules
     */
    public void init( Digester digester, PluginManager pm )
        throws PluginException
    {
        Log log = digester.getLogger();
        boolean debug = log.isDebugEnabled();
        if ( debug )
        {
            log.debug( "init being called!" );
        }

        if ( initialized )
        {
            throw new PluginAssertionFailure( "Init called multiple times." );
        }

        if ( ( pluginClass == null ) && ( pluginClassName != null ) )
        {
            try
            {
                // load the plugin class object
                pluginClass = digester.getClassLoader().loadClass( pluginClassName );
            }
            catch ( ClassNotFoundException cnfe )
            {
                throw new PluginException( "Unable to load class " + pluginClassName, cnfe );
            }
        }

        if ( ruleLoader == null )
        {
            // the caller didn't provide a ruleLoader to the constructor,
            // so get the plugin manager to "discover" one.
            log.debug( "Searching for ruleloader..." );
            ruleLoader = pm.findLoader( digester, id, pluginClass, properties );
        }
        else
        {
            log.debug( "This declaration has an explicit ruleLoader." );
        }

        if ( debug )
        {
            if ( ruleLoader == null )
            {
                log.debug( "No ruleLoader found for plugin declaration" + " id [" + id + "]" + ", class ["
                    + pluginClass.getClass().getName() + "]." );
            }
            else
            {
                log.debug( "RuleLoader of type [" + ruleLoader.getClass().getName()
                    + "] associated with plugin declaration" + " id [" + id + "]" + ", class ["
                    + pluginClass.getClass().getName() + "]." );
            }
        }

        initialized = true;
    }

    
Attempt to load custom rules for the target class at the specified pattern.

On return, any custom rules associated with the plugin class have been loaded into the Rules object currently
associated with the specified digester object.
Params:
digester – The Digester instance where plugin has to be plugged
pattern – The pattern the custom rules have to be bound
Throws:
PluginException – if any error occurs/**
     * Attempt to load custom rules for the target class at the specified pattern.
     * <p>
     * On return, any custom rules associated with the plugin class have been loaded into the Rules object currently
     * associated with the specified digester object.
     *
     * @param digester The Digester instance where plugin has to be plugged
     * @param pattern The pattern the custom rules have to be bound
     * @throws PluginException if any error occurs
     */
    public void configure( Digester digester, String pattern )
        throws PluginException
    {
        Log log = digester.getLogger();
        boolean debug = log.isDebugEnabled();
        if ( debug )
        {
            log.debug( "configure being called!" );
        }

        if ( !initialized )
        {
            throw new PluginAssertionFailure( "Not initialized." );
        }

        if ( ruleLoader != null )
        {
            ruleLoader.addRules( digester, pattern );
        }
    }

}