basestatemanagerservice.java

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/*
 * Copyright 2000-2002,2004 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
package org.apache.jetspeed.services.statemanager;

// imports
import java.util.Iterator;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Collections;
import javax.servlet.ServletConfig;
import javax.servlet.http.HttpSession;

import org.apache.turbine.services.TurbineBaseService;
import org.apache.turbine.services.InitializationException;
import org.apache.turbine.util.RunData;

import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
import org.apache.jetspeed.services.logging.JetspeedLogger;
import org.apache.jetspeed.services.statemanager.StateManagerService;
import org.apache.jetspeed.services.statemanager.SessionStateBindingListener;

/**
* <p>BaseStateManagerService is a Turbine Service implementation of the
* StateManagerService.</p>
* <p>Each SessionState is stored in a Map, storing the names and values
* of the state attributes.</p>
* <p>The set of states managed is stored in some specific way by extension classes.</p>
* <p>See the proposal: jakarta-jetspeed/proposals/StateManager.txt for more details.</p>
* @version $Revision: 1.5 $
* @see org.apache.jetspeed.services.statemanager.StateManagerService
* @see org.apache.jetspeed.services.statemanager.SessionState
* @author <a href="mailto:[e-mail]">Glenn R. Golden</a>
*/
public abstract class BaseStateManagerService
    extends TurbineBaseService
    implements StateManagerService
{
    /**
     * Static initialization of the logger for this class
     */    
    private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(BaseStateManagerService.class.getName());
    
    /** map of thread to http session for that thread. */
    protected Map m_httpSessions = null;

    /*******************************************************************************
    * Abstract methods
    *******************************************************************************/

    /**
    * Initialize the states storage.
    */
    protected abstract void initStates();

    /**
    * Cleanup the states storage.
    */
    protected abstract void shutdownStates();

    /**
    * Access the Map which is the set of attributes for a state.
    * @param key The state key.
    * @return The Map which is the set of attributes for a state.
    */
    protected abstract Map getState( String key );

    /**
    * Add a new state to the states we are managing.
    * @param key The state key.
    * @param state The Map which is the set of attributes for the state.
    */
    protected abstract void addState( String key, Map state );

    /**
    * Remove a state from the states we are managing.
    * @param key The state key.
    */
    protected abstract void removeState( String key );

    /**
    * Access an array of the keys of all states managed, those that start with the parameter.
    * @param start The starting string used to select the keys.
    * @return an array of the keys of all states managed.
    */
    protected abstract String[] getStateKeys( String start );

    /**
    * retire the attributes of the state.
    * @param key The state key.
    * @param state The Map of attributes to retire.
    */
    protected void retireAttributes( String key, Map state )
    {
        if (state == null) return;

        Set attributes = state.entrySet();
        synchronized (state)
        {
            Iterator i = attributes.iterator();
            while (i.hasNext())
            {
                Map.Entry attribute = (Map.Entry) i.next();
                unBindAttributeValue(key, (String)attribute.getKey(), attribute.getValue());
            }
        }

        // remove all attributes
        state.clear();

    }   // retireAttributes

    /**
    * If the object is a SessionStateBindingListener, unbind it
    * @param stateKey The state key.
    * @param attributeName The attribute name.
    * @param attribute The attribute object
    */
    protected void unBindAttributeValue( String stateKey, String attributeName, Object attribute )
    {
        // if this object wants session binding notification
        if ((attribute != null) && (attribute instanceof SessionStateBindingListener))
        {
            try
            {
                ((SessionStateBindingListener)attribute)
                    .valueUnbound(stateKey, attributeName);
            }
            catch (Throwable e) 
            {
                logger.warn("JetspeedStateManagerService.unBindAttributeValue: unbinding exception: ", e);
            }
        }

    }   // unBindAttributeValue

    /**
    * If the object is a SessionStateBindingListener, bind it
    * @param stateKey The state key.
    * @param attributeName The attribute name.
    * @param attribute The attribute object
    */
    protected void bindAttributeValue( String stateKey, String attributeName, Object attribute )
    {
        // if this object wants session binding notification
        if ((attribute != null) && (attribute instanceof SessionStateBindingListener))
        {
            try
            {
                ((SessionStateBindingListener)attribute)
                    .valueBound(stateKey, attributeName);
            }
            catch (Throwable e) 
            {
                logger.warn("JetspeedStateManagerService.bindAttributeValue: unbinding exception: ", e);
            }
        }

    }   // bindAttributeValue

    /*******************************************************************************
    * Service implementation
    *******************************************************************************/

    /**
    * Performs early initialization.
    *
    * @param config A ServletConfing to use for initialization
    * activities.
    * @exception InitializationException, if initialization of this
    * class was not successful.
    */
    public void init( ServletConfig config )
        throws InitializationException
    {
        super.init(config);

    }   // init

    /**
    * Performs early initialization.
    *
    * @param data An RunData to use for initialization activities.
    * @exception InitializationException, if initialization of this
    * class was not successful.
    */
    public void init( RunData data )
        throws InitializationException
    {
        super.init(data);

    }   // init

    /**
    * Performs late initialization.
    *
    * If your class relies on early initialization, and the object it
    * expects was not received, you can use late initialization to
    * throw an exception and complain.
    *
    * @exception InitializationException, if initialization of this
    * class was not successful.
    */
    public void init()
        throws InitializationException
    {
        super.init();

        // allocate a thread-safe map to store the "current" http session for each thread
        m_httpSessions = Collections.synchronizedMap(new HashMap());

        // create our states storage
        initStates();

    }   // init

    /**
    * Returns to uninitialized state.
    *
    * You can use this method to release resources thet your Service
    * allocated when Turbine shuts down.
    */
    public void shutdown()
    {
        m_httpSessions.clear();
        m_httpSessions = null;
        shutdownStates();
        super.shutdown();

    }   // shutdown

    /*******************************************************************************
    * StateManagerService implementation
    *******************************************************************************/

    /**
    * Access the named attribute of the keyed state.
    * @param key The state key.
    * @param name The attribute name.
    * @return The named attribute value of the keyed state.
    */
    public Object getAttribute ( String key, String name )
    {
        Map state = getState(key);
        if (state == null) return null;
        return state.get(name);

    }   // getAttribute

    /**
    * Set the named state attribute of the keyed state with the provided object.
    * @param key The state key.
    * @param name The attribute name.
    * @param value The new value of the attribute (any object type).
    */
    public void setAttribute( String key, String name, Object value )
    {
        Map state = getState(key);
        if (state == null)
        {
            // create a synchronized map to store the state attributes