MetaserverProcessor.java

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/*
 * This file is part of JXClient, the Fullscreen Java Crossfire Client.
 *
 * JXClient 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.
 *
 * JXClient 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 JXClient; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Copyright (C) 2005-2008 Yann Chachkoff
 * Copyright (C) 2006-2017,2019-2023 Andreas Kirschbaum
 * Copyright (C) 2010-2012,2014-2018,2020-2023 Nicolas Weeger
 */
 
package com.realtime.crossfire.jxclient.metaserver;
 
import com.realtime.crossfire.jxclient.guistate.ClientSocketState;
import com.realtime.crossfire.jxclient.guistate.GuiStateListener;
import com.realtime.crossfire.jxclient.guistate.GuiStateManager;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
 
public class MetaserverProcessor {
 
    private static final int UPDATE_INTERVAL = 15*60;
 
    private static final int MIN_UPDATE_INTERVAL = 5*60;
 
    private static final long EXPIRE_INTERVAL = 60L*60*24*2;
 
    @NotNull
    private final Collection<Metaserver> metaservers = new ArrayList<>();
 
    @NotNull
    private final MetaserverModel metaserverModel;
 
    @NotNull
    private final ServerCache serverCache;
 
    @NotNull
    private final Object sync = new Object();
 
    @Nullable
    private Thread thread;
 
    private boolean enabled;
 
    private long nextQuery = System.currentTimeMillis();
 
    private long lastQuery = nextQuery-MIN_UPDATE_INTERVAL*1000;
 
    @NotNull
    private final Runnable runnable = new Runnable() {
 
        @Override
        public void run() {
            try {
                while (!Thread.currentThread().isInterrupted()) {
                    synchronized (sync) {
                        if (enabled) {
                            final long now = System.currentTimeMillis();
                            final long delay = Math.max(nextQuery, lastQuery+MIN_UPDATE_INTERVAL*1000)-now;
                            if (delay > 0) {
                                sync.wait(delay);
                            } else {
                                nextQuery = now+UPDATE_INTERVAL*1000;
                                lastQuery = now;
                                for (final Metaserver metaserver : metaservers) {
                                    updateMetaList(metaserver);
                                }
                            }
                        } else {
                            //noinspection WaitOrAwaitWithoutTimeout
                            sync.wait();
                        }
                    }
                }
            } catch (final InterruptedException ignored) {
                // ignore
            }
        }
 
    };
 
    @NotNull
    @SuppressWarnings("FieldCanBeLocal")
    private final GuiStateListener guiStateListener = new GuiStateListener() {
 
        @Override
        public void start() {
            // ignore
        }
 
        @Override
        public void metaserver() {
            enable();
        }
 
        @Override
        public void preConnecting(@NotNull final String serverInfo) {
            // ignore
        }
 
        @Override
        public void connecting(@NotNull final String serverInfo) {
            disable();
        }
 
        @Override
        public void connecting(@NotNull final ClientSocketState clientSocketState, @NotNull final String param) {
            // ignore
        }
 
        @Override
        public void connected() {
            // ignore
        }
 
        @Override
        public void connectFailed(@NotNull final String reason) {
            // ignore
        }
 
    };
 
    public MetaserverProcessor(@NotNull final GuiStateManager guiStateManager, @Nullable final Path metaserverCacheFile, @NotNull final MetaserverModel metaserverModel) {
        this.metaserverModel = metaserverModel;
        serverCache = new ServerCache(metaserverCacheFile);
        guiStateManager.addGuiStateListener(guiStateListener);
        metaserverModel.begin();
        serverCache.getAll().values().forEach(metaserverModel::addMetaserverEntry);
        metaserverModel.commit();
    }
 
    public void addMetaserver(@NotNull final Metaserver metaserver) {
        synchronized (sync) {
            metaservers.add(metaserver);
        }
    }
 
    public void start() {
        synchronized (sync) {
            if (thread == null) {
                thread = new Thread(runnable, "JXClient:MetaserverProcessor");
                thread.setDaemon(true);
                thread.start();
            }
            nextQuery = System.currentTimeMillis();
            sync.notifyAll();
        }
    }
 
    public void stop() {
        synchronized (sync) {
            if (thread != null) {
                try {
                    thread.interrupt();
                    sync.notifyAll();
                    try {
                        thread.join(5000);
                    } catch (final InterruptedException ex) {
                        //noinspection UseOfSystemOutOrSystemErr
                        System.err.println("Cannot stop metaserver thread: "+ex);
                    }
                } finally {
                    thread = null;
                }
            }
        }
    }
 
    private void disable() {
        synchronized (sync) {
            enabled = false;
            sync.notifyAll();
        }
    }
 
    private void enable() {
        synchronized (sync) {
            enabled = true;
            nextQuery = System.currentTimeMillis();
            sync.notifyAll();
        }
    }
 
    private void updateMetaList(@NotNull final Metaserver metaserver) {
        metaserverModel.begin();
 
        serverCache.expire(EXPIRE_INTERVAL*1000);
        final Map<String, MetaserverEntry> oldEntries = serverCache.getAll();
 
        for (final MetaserverEntry metaserverEntry : metaserver.queryMetaserver()) {
            metaserverModel.addMetaserverEntry(metaserverEntry);
            oldEntries.remove(metaserverEntry.getKey());
            serverCache.put(metaserverEntry);
        }
 
        // add previously known entries that are not anymore present
        oldEntries.values().forEach(metaserverModel::addMetaserverEntry);
 
        metaserverModel.commit();
        serverCache.save();
    }
 
}