/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.catalina.tribes.group.interceptors;
import java.lang.ref.WeakReference;
import java.util.Arrays;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelInterceptor;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.group.ChannelInterceptorBase;
import org.apache.catalina.tribes.io.ChannelData;
import org.apache.catalina.tribes.io.XByteBuffer;
/**
*
* Sends a ping to all members.
* Configure this interceptor with the TcpFailureDetector below it,
* and the TcpFailureDetector will act as the membership guide.
* @author Filip Hanik
* @version 1.0
*/
public class TcpPingInterceptor extends ChannelInterceptorBase {
protected static org.apache.juli.logging.Log log =
org.apache.juli.logging.LogFactory.getLog(TcpPingInterceptor.class);
protected static byte[] TCP_PING_DATA = new byte[] {
79, -89, 115, 72, 121, -33, 67, -55, -97, 111, -119, -128, -95, 91, 7, 20,
125, -39, 82, 91, -21, -33, 67, -102, -73, 126, -66, -113, -127, 103, 30, -74,
55, 21, -66, -121, 69, 33, 76, -88, -65, 10, 77, 19, 83, 56, 21, 50,
85, -10, -108, -73, 58, -33, 33, 120, -111, 4, 125, -41, 114, -124, -64, -43};
protected long interval = 1000; //1 second
protected boolean useThread = false;
protected boolean staticOnly = false;
protected boolean running = true;
protected PingThread thread = null;
protected static AtomicInteger cnt = new AtomicInteger(0);
WeakReference<TcpFailureDetector> failureDetector = null;
WeakReference<StaticMembershipInterceptor> staticMembers = null;
public synchronized void start(int svc) throws ChannelException {
super.start(svc);
running = true;
if ( thread == null && useThread) {
thread = new PingThread();
thread.setDaemon(true);
thread.setName("TcpPingInterceptor.PingThread-"+cnt.addAndGet(1));
thread.start();
}
//acquire the interceptors to invoke on send ping events
ChannelInterceptor next = getNext();
while ( next != null ) {
if ( next instanceof TcpFailureDetector )
failureDetector = new WeakReference<TcpFailureDetector>((TcpFailureDetector)next);
if ( next instanceof StaticMembershipInterceptor )
staticMembers = new WeakReference<StaticMembershipInterceptor>((StaticMembershipInterceptor)next);
next = next.getNext();
}
}
public void stop(int svc) throws ChannelException {
running = false;
if ( thread != null ) {
thread.interrupt();
thread = null;
}
super.stop(svc);
}
public void heartbeat() {
super.heartbeat();
if (!getUseThread()) sendPing();
}
public long getInterval() {
return interval;
}
public void setInterval(long interval) {
this.interval = interval;
}
public void setUseThread(boolean useThread) {
this.useThread = useThread;
}
public void setStaticOnly(boolean staticOnly) {
this.staticOnly = staticOnly;
}
public boolean getUseThread() {
return useThread;
}
public boolean getStaticOnly() {
return staticOnly;
}
protected void sendPing() {
TcpFailureDetector tcpFailureDetector =
failureDetector != null ? failureDetector.get() : null;
if (tcpFailureDetector != null) {
// We have a reference to the failure detector
// Piggy back on it
tcpFailureDetector.checkMembers(true);
} else {
StaticMembershipInterceptor smi =
staticOnly && staticMembers != null ? staticMembers.get() : null;
if (smi != null) {
sendPingMessage(smi.getMembers());
} else {
sendPingMessage(getMembers());
}
}
}
protected void sendPingMessage(Member[] members) {
if ( members == null || members.length == 0 ) return;
ChannelData data = new ChannelData(true);//generates a unique Id
data.setAddress(getLocalMember(false));
data.setTimestamp(System.currentTimeMillis());
data.setOptions(getOptionFlag());
data.setMessage(new XByteBuffer(TCP_PING_DATA, false));
try {
super.sendMessage(members, data, null);
}catch (ChannelException x) {
log.warn("Unable to send TCP ping.",x);
}
}
public void messageReceived(ChannelMessage msg) {
//catch incoming
boolean process = true;
if ( okToProcess(msg.getOptions()) ) {
//check to see if it is a ping message, if so, process = false
process = ( (msg.getMessage().getLength() != TCP_PING_DATA.length) ||
(!Arrays.equals(TCP_PING_DATA,msg.getMessage().getBytes()) ) );
}//end if
//ignore the message, it doesnt have the flag set
if ( process ) super.messageReceived(msg);
else if ( log.isDebugEnabled() ) log.debug("Received a TCP ping packet:"+msg);
}//messageReceived
protected class PingThread extends Thread {
public void run() {
while (running) {
try {
sleep(interval);
sendPing();
}catch ( InterruptedException ix ) {
interrupted();
}catch ( Exception x ) {
log.warn("Unable to send ping from TCP ping thread.",x);
}
}
}
}
}