FollowAction.java

// BlogBridge -- RSS feed reader, manager, and web based service
// Copyright (C) 2002-2006 by R. Pito Salas
//
// This program is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free Software Foundation;
// either version 2 of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with this program;
// if not, write to the Free Software Foundation, Inc., 59 Temple Place,
// Suite 330, Boston, MA 02111-1307 USA
//
// Contact: R. Pito Salas
// mailto:pitosalas@users.sourceforge.net
// More information: about BlogBridge
// http://www.blogbridge.com
// http://sourceforge.net/projects/blogbridge
//
// $Id$
//

package com.salas.bb.twitter;

import com.salas.bb.utils.i18n.Strings;
import oauth.signpost.exception.OAuthException;

import javax.swing.*;
import java.io.IOException;
import java.net.URL;

/**
 * (Un)follow action.
 */
public class FollowAction extends AbstractTwitterAction
{

    private static FollowAction instance;

    private final Object lock = new Object();

    private URL         userURL;
    private String      screenName;
    private boolean     followAction;
    private boolean     myself;

    /** Creates action. */
    private FollowAction()
    {
        update(false, Strings.message("twitter.unknown"));
    }

    /**
     * Returns instance.
     *
     * @return instance.
     */
    public static synchronized FollowAction getInstance()
    {
        if (instance == null) instance = new FollowAction();
        return instance;
    }

    /**
     * Sets user URL.
     *
     * @param url URL.
     */
    public void setUserURL(URL url)
    {
        synchronized (lock)
        {
            if (userURL == null || url == null || !userURL.toString().equalsIgnoreCase(url.toString()))
            {
                userURL = url;
                checkAndUpdate(url);
            }
        }
    }

    /**
     * Custom action.
     */
    protected void customAction()
    {
        synchronized (lock)
        {
            if (userURL == null) return;

            try
            {
                if (followAction) TwitterGateway.follow(screenName); else TwitterGateway.unfollow(screenName);
                followAction = !followAction;
                update(true, actionLabel(!followAction));
            } catch (IOException e1)
            {
                e1.printStackTrace();
                // Ignore
            } catch (OAuthException e)
            {
                e.printStackTrace();
                // Ignore for now - TODO possibly show some warning box and direct to the setting pane
            }
        }
    }

    /**
     * Checks the status of the friendship between two people.
     *
     * @param url URL of the user.
     */
    private void checkAndUpdate(final URL url)
    {
        update(false, Strings.message("twitter.checking"));

        if (url == null)
        {
            update(false, Strings.message("twitter.unavailable"));
            return;
        }

        if (!TwitterFeature.isConfigured())
        {
            update(true, Strings.message("twitter.follow"));
            return;
        }

        final String name = TwitterGateway.urlToScreenName(url);
        if (name != null)
        {
            if (name.equalsIgnoreCase(getPreferences().getScreenName()))
            {
                update(false, Strings.message("twitter.myself"));
                myself = true;
            } else
            {
                myself = false;
                new Thread("Follows?")
                {
                    public void run()
                    {
                        boolean following = false;
                        boolean error = false;

                        try
                        {
                            following = TwitterGateway.isFollowing(name);
                        } catch (IOException e)
                        {
                            error = true;
                        }

                        updateState(following, error, name, url);
                    }
                }.start();
            }
        }
    }

    private void update(boolean enabled, String text)
    {
        setEnabled(enabled);
        putValue("Name", text);
    }

    private void updateState(final boolean following, final boolean error, final String name, final URL url)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                synchronized (lock)
                {
                    // If it is still the same URL
                    if (userURL == url)
                    {
                        followAction = !following;
                        screenName   = name;

                        update(!error, error ? Strings.message("twitter.unknown") : actionLabel(following));
                    }
                }
            }
        });
    }

    private String actionLabel(boolean following)
    {
        return following ? Strings.message("twitter.unfollow") : Strings.message("twitter.follow");
    }

    /**
     * Returns TRUE if the action can be performed.
     *
     * @return TRUE if the action can be performed.
     */
    public boolean isAvailable()
    {
        return !myself;
    }
}