org.rdv.data.LocalChannelManager.java Source code

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Here is the source code for org.rdv.data.LocalChannelManager.java

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/*
 * RDV
 * Real-time Data Viewer
 * http://rdv.googlecode.com/
 * 
 * Copyright (c) 2008 Palta Software
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 * 
 * $URL$
 * $Revision$
 * $Date$
 * $Author$
 */

package org.rdv.data;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.rdv.rbnb.RBNBController;

import com.rbnb.sapi.ChannelTree;
import com.rbnb.sapi.LocalChannelMap;

/**
 * A class to manage instances of <code>LocalChannel</code>.
 * 
 * @author Jason P. Hanley
 * @see    LocalChannel
 */
public class LocalChannelManager {

    /** the log for this class */
    private static Log log = LogFactory.getLog(LocalChannelManager.class.getName());

    /** the single instance for this class */
    private static LocalChannelManager instance;

    /** the list of local channels, iterators over this must be synchronized */
    private final List<LocalChannel> channels;

    /**
     * Gets the instance of this class
     * 
     * @return  the instance of this class
     */
    public static LocalChannelManager getInstance() {
        if (instance == null) {
            instance = new LocalChannelManager();
        }

        return instance;
    }

    /**
     * Creates the local channel manager.
     */
    private LocalChannelManager() {
        channels = Collections.synchronizedList(new ArrayList<LocalChannel>());
    }

    /**
     * Determines whether any channels have been added.
     * 
     * @return  true if there are channels, false otherwise
     */
    public boolean hasChannels() {
        return !channels.isEmpty();
    }

    /**
     * Gets the local channel named <code>channelName</code>. If no such channel
     * with this name exists, null is returned.
     * 
     * @param channelName  the channel name to get
     * @return             the channel with this name or null if none is found
     */
    public LocalChannel getChannel(String channelName) {
        synchronized (channels) {
            for (LocalChannel channel : channels) {
                if (channel.getName().equals(channelName)) {
                    return channel;
                }
            }
        }

        return null;
    }

    /**
     * Gets a list of <code>LocalChannel</code>'s being managed by this class.
     * 
     * @return  a list of local channels
     */
    public List<LocalChannel> getChannels() {
        return Collections.unmodifiableList(channels);
    }

    /**
     * Adds <code>channel</code> to this class and starts posting metadata and
     * data to it.
     * 
     * @param channel  the channel to add
     */
    public void addChannel(LocalChannel channel) {
        channels.add(channel);

        RBNBController.getInstance().updateMetadata();
    }

    /**
     * Removes the <code>LocalChannel</code>'s with <code>channelNames</code> from
     * this class.
     * 
     * @param channelNames  the list of channel to remove
     * @see             LocalChannel#dispose()
     */
    public void removeChannels(List<String> channelNames) {
        synchronized (channels) {
            Iterator<LocalChannel> i = channels.iterator();
            while (i.hasNext()) {
                LocalChannel channel = i.next();
                if (channelNames.contains(channel.getName())) {
                    i.remove();
                }
            }
        }

        RBNBController.getInstance().updateMetadata();
    }

    /**
     * Removes all the <code>LocalChannel</code>'s from this class.
     */
    public void removeAllChannels() {
        channels.clear();

        RBNBController.getInstance().updateMetadata();
    }

    /**
     * Updates the metadata for all <code>LocalChannel</code>'s being managed by
     * this class.
     * 
     * @param channelMap         the channel map to post the metadata to
     * @param serverChannelTree  the channel tree of server channels
     * @return                   a map of channels to their user data
     */
    public ChannelTree getMetadata(ChannelTree serverChannelTree) {
        LocalChannelMap channelMap = new LocalChannelMap();

        synchronized (channels) {
            for (LocalChannel channel : channels) {
                try {
                    channel.updateMetadata(channelMap, serverChannelTree);
                } catch (Exception e) {
                    log.warn("Error updating metadata for local channel " + channel.getName() + ": "
                            + e.getMessage());
                    e.printStackTrace();
                }
            }
        }

        try {
            channelMap.mergeLocalData();
        } catch (Exception e) {
            log.warn("Failed to merge local channel metadata: " + e.getMessage());
            e.printStackTrace();
        }

        ChannelTree channelTree = ChannelTree.createFromChannelMap(channelMap);

        return channelTree;
    }

    /**
     * Updates data for all <code>LocalChannel</code>'s being managed by this
     * class.
     * 
     * @param channelMap  the channel map to post data to
     */
    public void updateData(LocalChannelMap channelMap) {
        synchronized (channels) {
            for (LocalChannel channel : channels) {
                try {
                    channel.updateData(channelMap);
                } catch (Exception e) {
                    log.warn("Error updating data for local channel " + channel.getName() + ": " + e.getMessage());
                    e.printStackTrace();
                }
            }
        }

        try {
            channelMap.mergeLocalData();
        } catch (Exception e) {
            log.warn("Failed to merge local channel data with server data: " + e.getMessage());
            e.printStackTrace();
        }
    }

}