org.eclipse.virgo.ide.runtime.core/src/org/eclipse/virgo/ide/runtime/internal/core/ServerStatusPingThread.java

/*********************************************************************
 * Copyright (c) 2009, 2012 SpringSource, a division of VMware, Inc.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
**********************************************************************/

package org.eclipse.virgo.ide.runtime.internal.core;

import java.io.IOException;

import org.eclipse.virgo.ide.runtime.internal.core.utils.StatusUtil;

/**
 * Ping thread the tries to connect to the dm server and listens to the recovery notification.
 * <p>
 * This is used to test if a server is running after it has been started by the server view.
 *
 * @author Christian Dupuis
 * @since 1.0.0
 */
public class ServerStatusPingThread {

    /** Delay after which the thread should start pinging */
    private static final int PING_DELAY = 3000;

    /** Interval in which the thread to ping the server */
    private static final int PING_INTERVAL = 1000;

    /** Indicate that the thread should stop pinging */
    private boolean stop = false;

    /** Reference to the server the user has started on the UI */
    private final ServerBehaviour behaviour;

    /**
     * Creates a new {@link ServerStatusPingThread}
     */
    protected ServerStatusPingThread(ServerBehaviour behaviour) {
        this.behaviour = behaviour;
        Thread t = new Thread("SpringSource dm Server Ping Thread") {

            @Override
            public void run() {
                ping();
            }
        };
        t.setDaemon(true);
        t.start();
    }

    protected void ping() {
        try {
            Thread.sleep(PING_DELAY);
        } catch (Exception e) {
            // ignore
        }
        while (!this.stop) {
            try {

                Boolean value = this.behaviour.getServerDeployer().ping();
                if (!this.stop && value != null && value.booleanValue()) {
                    // ping worked - server is up
                    this.stop = true;
                    this.behaviour.setServerStarted();
                } else {
                    sleep();
                }
            } catch (IOException se) {
                sleep();
            } catch (Exception e) {
                StatusUtil.error("Server startup ping failed", e);
                // pinging failed
                if (!this.stop) {
                    sleep();
                }
            }
        }
    }

    /**
     * Sends this thread to sleep for the configured timeout
     */
    private void sleep() {
        try {
            Thread.sleep(PING_INTERVAL);
        } catch (InterruptedException e) {
        }
    }

    /**
     * Stops this thread from pinging the dm Server instance
     */
    public void stop() {
        this.stop = true;
    }

}