com.clustercontrol.plugin.HinemosPluginService.java Source code

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Here is the source code for com.clustercontrol.plugin.HinemosPluginService.java

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/*
    
Copyright (C) 2012 NTT DATA Corporation
    
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, version 2.
    
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.
    
 */

package com.clustercontrol.plugin;

import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.clustercontrol.plugin.api.HinemosPlugin;
import com.clustercontrol.plugin.api.HinemosPlugin.PluginStatus;

/**
 * HinemosPlugin??(Singleton).
 * 
 */
public class HinemosPluginService {

    public static final Log log = LogFactory.getLog(HinemosPluginService.class);

    private static final HinemosPluginService _instance = new HinemosPluginService();

    // ?????
    private final Map<String, HinemosPlugin> pluginMap = new ConcurrentHashMap<String, HinemosPlugin>();
    // ????
    private final Map<String, PluginStatus> pluginStatusMap = new ConcurrentHashMap<String, PluginStatus>();

    // activate???????????
    private final List<HinemosPlugin> pluginActivatationOrder = new ArrayList<HinemosPlugin>();

    /**
     * private(Singleton).
     */
    private HinemosPluginService() {
        String pluginDir = System.getProperty("hinemos.manager.home.dir") + File.separator + "plugins";
        try {
            // /opt/hinemos/plugins??jar??
            ClassUtils.addDirToClasspath(new File(pluginDir));
            log.info("initialized plugin directory : " + pluginDir);
        } catch (Exception e) {
            log.warn("classpath configure failure. (pluginDir = " + pluginDir + ")", e);
        }

        ServiceLoader<HinemosPlugin> serviceLoader = ServiceLoader.load(HinemosPlugin.class);
        Iterator<HinemosPlugin> itr = serviceLoader.iterator();
        while (itr.hasNext()) {
            HinemosPlugin plugin = itr.next();

            pluginMap.put(plugin.getClass().getName(), plugin);
            pluginStatusMap.put(plugin.getClass().getName(), PluginStatus.NULL);
        }

    }

    /**
     * JVM???HinemosPluginService?.
     * 
     * @return HinemosPluginService
     */
    public static HinemosPluginService getInstance() {
        return _instance;
    }

    /**
     * HinemosPlugin????.
     */
    public synchronized void create() {
        for (Map.Entry<String, HinemosPlugin> set : pluginMap.entrySet()) {
            try {
                log.info("creating plugin - " + set.getKey());
                pluginStatusMap.put(set.getValue().getClass().getName(), PluginStatus.DEACTIVATED);
                set.getValue().create();
            } catch (Throwable t) {
                log.warn("plugin creation failure.", t);
            }
        }
    }

    /**
     * HinemosPlugin???.
     * 
     * <p>
     * {@link com.clustercontrol.plugin.api.HinemosPlugin.getDependency()}???
     * ????????????
     * </p>
     */
    public synchronized void activate() {
        List<HinemosPlugin> waitingPlugin = new ArrayList<HinemosPlugin>(pluginMap.values());
        pluginActivatationOrder.clear();

        while (true) {
            boolean nonActivatable = true;

            for (HinemosPlugin plugin : waitingPlugin) {
                if (pluginStatusMap.get(plugin.getClass().getName()) == PluginStatus.ACTIVATED) {
                    // ?activate????????
                    continue;
                }

                if (isPluginActivatable(plugin)) {
                    // ???????activate??
                    log.info("activating plugin - " + plugin.getClass().getName());

                    nonActivatable = false;
                    pluginStatusMap.put(plugin.getClass().getName(), PluginStatus.ACTIVATED);
                    pluginActivatationOrder.add(plugin);

                    try {
                        plugin.activate();
                    } catch (Throwable t) {
                        log.warn("plugin activation failure.", t);
                    }
                }
            }

            // ??????
            waitingPlugin.removeAll(pluginActivatationOrder);

            if (nonActivatable) {
                if (waitingPlugin.size() == 0) {
                    // ????????
                    break;
                }

                // ?????????????????WARN???
                for (HinemosPlugin plugin : waitingPlugin) {
                    log.warn(String.format("plugin %s is not started because of dependency : %s",
                            plugin.getClass().getName(), plugin.getDependency()));
                }
                log.warn("some plugin may be not activated bevcause of dependency.");
                break;
            }
        }
    }

    /**
     * ????HinemosPlugin???HinemosPlugin???????????.
     * 
     * @param plugin ??????HinemosPlugin
     * @return true : ??false : ??
     */
    private boolean isPluginActivatable(HinemosPlugin plugin) {
        boolean activatable = true;

        log.debug("checking dependency of " + plugin.getClass().getName() + " : " + plugin.getDependency());

        for (String className : plugin.getDependency()) {
            log.debug("checking plugin status of " + className + " : " + pluginStatusMap.get(className));
            if (pluginStatusMap.get(className) != PluginStatus.ACTIVATED) {
                activatable = false;
                break;
            }
        }

        return activatable;
    }

    /**
     * HinemosPlugin????.
     * 
     * <p>
     * {@link com.clustercontrol.plugin.HinemosPluginService.activate()}?????????
     * ??deactivate???
     * </p>
     */
    public synchronized void deactivate() {
        List<HinemosPlugin> pluginDeactivationOrder = new ArrayList<HinemosPlugin>(pluginActivatationOrder);
        Collections.reverse(pluginDeactivationOrder);

        for (HinemosPlugin plugin : pluginDeactivationOrder) {
            try {
                log.info("deactivating plugin - " + plugin.getClass().getName());
                pluginStatusMap.put(plugin.getClass().getName(), PluginStatus.DEACTIVATED);
                plugin.deactivate();
            } catch (Throwable t) {
                log.warn("plugin deactivation failure.", t);
            }
        }
    }

    /**
     * HinemosPlugin???.
     */
    public synchronized void destroy() {
        for (Map.Entry<String, HinemosPlugin> set : pluginMap.entrySet()) {
            try {
                log.info("destroying plugin - " + set.getKey());
                pluginStatusMap.put(set.getValue().getClass().getName(), PluginStatus.NULL);
                set.getValue().destroy();
            } catch (Throwable t) {
                log.warn("plugin destroying failure.", t);
            }
        }
    }
}