/*
 * Copyright 2000-2004 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.jetspeed.om.registry.base;

import org.apache.jetspeed.om.registry.ClientEntry;
import org.apache.jetspeed.om.registry.ClientRegistry;
import org.apache.jetspeed.om.registry.RegistryEntry;
import org.apache.jetspeed.om.registry.InvalidEntryException;
import org.apache.jetspeed.om.registry.RegistryException;
import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
import org.apache.jetspeed.services.logging.JetspeedLogger;
import org.apache.jetspeed.services.Registry;
import java.util.Enumeration;

// regexp stuff
import org.apache.regexp.RE;

/**
 * Simple implementation of the ClientRegistry interface.
 * <p>Extends BaseRegistry implementation to override object creation
 * method and ensure Registry object is synchronized with its
 * persistence backend by delegating actual addition/deletion of objects
 * to the registry service.</p>
 * <p>To avoid loops, a RegistryService implementation using this class
 * nees to call the addLocalEntry/removeLocalEntry methods to modify
 * the in memory state of this Registry</p>
 *
 * @author <a href="shesmer@raleigh.ibm.com">Stephan Hesmer</a>
 * @author <a href="mailto:raphael@apache.org">Raphaël Luta</a>
 * @version $Id: BaseClientRegistry.java,v 1.5 2004/02/23 03:08:26 jford Exp $
 */
public class BaseClientRegistry extends BaseOrderedRegistry implements ClientRegistry
{
    
    /**
     * Static initialization of the logger for this class
     */    
    private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(BaseClientRegistry.class.getName());    
    
    /**
    @see Registry#setEntry
    */
    public void setEntry( RegistryEntry entry ) throws InvalidEntryException
    {
        // Delegate to the RegistryService to ensure correct handling of
        // persistence if using file fragments

        try
        {
            Registry.addEntry(Registry.CLIENT, entry);
        }
        catch (RegistryException e)
        {
            logger.error("Exception", e);
        }
    }

    /**
    @see Registry#addEntry
    */
    public void addEntry( RegistryEntry entry ) throws InvalidEntryException
    {
        // Delegate to the RegistryService to ensure correct handling of
        // persistence if using file fragments

        try
        {
            Registry.addEntry(Registry.CLIENT, entry);
        }
        catch (RegistryException e)
        {
            logger.error("Exception", e);
        }
    }

    /**
    @see Registry#removeEntry
    */
    public void removeEntry( String name )
    {
        // Delegate to the RegistryService to ensure correct handling of
        // persistence if using file fragments

        Registry.removeEntry(Registry.CLIENT, name);
    }

    /**
    @see Registry#removeEntry
    */
    public void removeEntry( RegistryEntry entry )
    {
        // Delegate to the RegistryService to ensure correct handling of
        // persistence if using file fragments

        if (entry != null)
        {
            Registry.removeEntry(Registry.CLIENT, entry.getName());
        }
    }

    /**
     * Returns the client which matches the given useragent string.
     *
     * @param useragent     the useragent to match
     * @return the found client or null if the user-agent does not match any
     *  defined client
     */
    public ClientEntry findEntry(String useragent)
    {
        ClientEntry clientEntry = null;
        Enumeration clients = getEntries();

        if ( logger.isDebugEnabled() )
        {
            logger.debug( "ClientRegistry: Looking for client with useragent :" + useragent );
        }

        if (clients != null)
        {
            while (clients.hasMoreElements())
            {
                ClientEntry client = (ClientEntry)clients.nextElement();
                if (client.getUseragentpattern() != null)
                {
                    try
                    {
                        RE r = new RE(client.getUseragentpattern());
                        r.setMatchFlags(RE.MATCH_CASEINDEPENDENT);

                        if (r.match(useragent))
                        {

                            if ( logger.isDebugEnabled() )
                            {
                                logger.debug( "ClientRegistry: " + useragent + " matches " + client.getUseragentpattern() );
                            }

                            return client;
                        }
                        else
                        {
                            if ( logger.isDebugEnabled() )
                            {
                                logger.debug( "ClientRegistry: " + useragent + " does not match " + client.getUseragentpattern() );
                            }
                        }
                    }
                    catch (org.apache.regexp.RESyntaxException e)
                    {
                        String message = "ClientRegistryService: UserAgentPattern not valid : " + client.getUseragentpattern() + " : " + e.getMessage();
                        logger.error( message, e );
                    }
                }
            }
        }

        return clientEntry;
    }

    /**
     * Creates a new RegistryEntry instance compatible with the current
     * Registry instance implementation
     *
     * @return the newly created RegistryEntry
     */
    public RegistryEntry createEntry()
    {
        return new BaseClientEntry();
    }
}
