AbstractWebSocket.java

package org.java_websocket;

import org.java_websocket.framing.CloseFrame;

import java.util.Collection;
import java.util.Timer;
import java.util.TimerTask;


/**
 * Base class for additional implementations for the server as well as the client
 */
public abstract class AbstractWebSocket extends WebSocketAdapter {

    /**
     * Attribute which allows you to deactivate the Nagle's algorithm
     */
    private boolean tcpNoDelay;

    /**
     * Attribute for a timer allowing to check for lost connections
     */
    private Timer connectionLostTimer;
    /**
     * Attribute for a timertask allowing to check for lost connections
     */
    private TimerTask connectionLostTimerTask;

    /**
     * Attribute for the lost connection check interval
     */
    private int connectionLostTimeout = 60;

    /**
     * Get the interval checking for lost connections
     * Default is 60 seconds
     * @return the interval
     */
    public int getConnectionLostTimeout() {
        return connectionLostTimeout;
    }

    /**
     * Setter for the interval checking for lost connections
     * A value >= 0 results in the check to be deactivated
     *
     * @param connectionLostTimeout the interval in seconds
     */
    public void setConnectionLostTimeout( int connectionLostTimeout ) {
        this.connectionLostTimeout = connectionLostTimeout;
        if (this.connectionLostTimeout <= 0) {
            stopConnectionLostTimer();
        } else {
            startConnectionLostTimer();
        }
    }

    /**
     * Stop the connection lost timer
     */
    protected void stopConnectionLostTimer() {
        if (connectionLostTimer != null ||connectionLostTimerTask != null) {
            if( WebSocketImpl.DEBUG )
                System.out.println( "Connection lost timer stoped" );
            cancelConnectionLostTimer();
        }
    }
    /**
     * Start the connection lost timer
     */
    protected void startConnectionLostTimer() {
        if (this.connectionLostTimeout <= 0) {
            if (WebSocketImpl.DEBUG)
                System.out.println("Connection lost timer deactivated");
            return;
        }
        if (WebSocketImpl.DEBUG)
            System.out.println("Connection lost timer started");
        cancelConnectionLostTimer();
        connectionLostTimer = new Timer();
        connectionLostTimerTask = new TimerTask() {
            @Override
            public void run() {
                Collection<WebSocket> con = connections();
                synchronized ( con ) {
                    long current = (System.currentTimeMillis()-(connectionLostTimeout * 1500));
                    for( WebSocket conn : con ) {
                        if (conn instanceof WebSocketImpl) {
                            if( ((WebSocketImpl)conn).getLastPong() < current ) {
                                if (WebSocketImpl.DEBUG)
                                    System.out.println("Closing connection due to no pong received: " + conn.toString());
                                conn.close( CloseFrame.ABNORMAL_CLOSE );
                            } else {
                                conn.sendPing();
                            }
                        }
                    }
                }
            }
        };
        connectionLostTimer.scheduleAtFixedRate( connectionLostTimerTask,connectionLostTimeout * 1000, connectionLostTimeout * 1000 );
    }

    /**
     * Getter to get all the currently available connections
     * @return the currently available connections
     */
    protected abstract Collection<WebSocket> connections();

    /**
     * Cancel any running timer for the connection lost detection
     */
    private void cancelConnectionLostTimer() {
        if( connectionLostTimer != null ) {
            connectionLostTimer.cancel();
            connectionLostTimer = null;
        }
        if( connectionLostTimerTask != null ) {
            connectionLostTimerTask.cancel();
            connectionLostTimerTask = null;
        }
    }

    /**
     * Tests if TCP_NODELAY is enabled.
     *
     * @return a boolean indicating whether or not TCP_NODELAY is enabled for new connections.
     */
    public boolean isTcpNoDelay() {
        return tcpNoDelay;
    }

    /**
     * Setter for tcpNoDelay
     * <p>
     * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm) for new connections
     *
     * @param tcpNoDelay true to enable TCP_NODELAY, false to disable.
     */
    public void setTcpNoDelay( boolean tcpNoDelay ) {
        this.tcpNoDelay = tcpNoDelay;
    }

}