/*
* Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package com.sun.jmx.remote.internal;
import java.io.IOException;
import java.io.InterruptedIOException;
import com.sun.jmx.remote.util.ClassLogger;
import com.sun.jmx.remote.util.EnvHelp;
public abstract class ClientCommunicatorAdmin {
private static volatile long threadNo = 1;
public ClientCommunicatorAdmin(long period) {
this.period = period;
if (period > 0) {
checker = new Checker();
Thread t = new Thread(checker, "JMX client heartbeat " + ++threadNo);
t.setDaemon(true);
t.start();
} else
checker = null;
}
/**
* Called by a client to inform of getting an IOException.
*/
public void gotIOException (IOException ioe) throws IOException {
restart(ioe);
}
/**
* Called by this class to check a client connection.
*/
protected abstract void checkConnection() throws IOException;
/**
* Tells a client to re-start again.
*/
protected abstract void doStart() throws IOException;
/**
* Tells a client to stop because failing to call checkConnection.
*/
protected abstract void doStop();
/**
* Terminates this object.
*/
public void terminate() {
synchronized(lock) {
if (state == TERMINATED) {
return;
}
state = TERMINATED;
lock.notifyAll();
if (checker != null)
checker.stop();
}
}
private void restart(IOException ioe) throws IOException {
// check state
synchronized(lock) {
if (state == TERMINATED) {
throw new IOException("The client has been closed.");
} else if (state == FAILED) { // already failed to re-start by another thread
throw ioe;
} else if (state == RE_CONNECTING) {
// restart process has been called by another thread
// we need to wait
while(state == RE_CONNECTING) {
try {
lock.wait();
} catch (InterruptedException ire) {
// be asked to give up
InterruptedIOException iioe = new InterruptedIOException(ire.toString());
EnvHelp.initCause(iioe, ire);
throw iioe;
}
}
if (state == TERMINATED) {
throw new IOException("The client has been closed.");
} else if (state != CONNECTED) {
// restarted is failed by another thread
throw ioe;
}
return;
} else {
state = RE_CONNECTING;
lock.notifyAll();
}
}
// re-starting
try {
doStart();
synchronized(lock) {
if (state == TERMINATED) {
throw new IOException("The client has been closed.");
}
state = CONNECTED;
lock.notifyAll();
}
return;
} catch (Exception e) {
logger.warning("restart", "Failed to restart: " + e);
logger.debug("restart",e);
synchronized(lock) {
if (state == TERMINATED) {
throw new IOException("The client has been closed.");
}
state = FAILED;
lock.notifyAll();
}
try {
doStop();
} catch (Exception eee) {
// OK.
// We know there is a problem.
}
terminate();
throw ioe;
}
}
// --------------------------------------------------------------
// private varaibles
// --------------------------------------------------------------
private class Checker implements Runnable {
public void run() {
myThread = Thread.currentThread();
while (state != TERMINATED && !myThread.isInterrupted()) {
try {
Thread.sleep(period);
} catch (InterruptedException ire) {
// OK.
// We will check the state at the following steps
}
if (state == TERMINATED || myThread.isInterrupted()) {
break;
}
try {
checkConnection();
} catch (Exception e) {
synchronized(lock) {
if (state == TERMINATED || myThread.isInterrupted()) {
break;
}
}
e = (Exception)EnvHelp.getCause(e);
if (e instanceof IOException &&
!(e instanceof InterruptedIOException)) {
try {
gotIOException((IOException)e);
} catch (Exception ee) {
logger.warning("Checker-run",
"Failed to check connection: "+ e);
logger.warning("Checker-run", "stopping");
logger.debug("Checker-run",e);
break;
}
} else {
logger.warning("Checker-run",
"Failed to check the connection: " + e);
logger.debug("Checker-run",e);
// XXX stop checking?
break;
}
}
}
if (logger.traceOn()) {
logger.trace("Checker-run", "Finished.");
}
}
private void stop() {
if (myThread != null && myThread != Thread.currentThread()) {
myThread.interrupt();
}
}
private Thread myThread;
}
// --------------------------------------------------------------
// private variables
// --------------------------------------------------------------
private final Checker checker;
private long period;
// state
private final static int CONNECTED = 0;
private final static int RE_CONNECTING = 1;
private final static int FAILED = 2;
private final static int TERMINATED = 3;
private int state = CONNECTED;
private final int[] lock = new int[0];
private static final ClassLogger logger =
new ClassLogger("javax.management.remote.misc",
"ClientCommunicatorAdmin");
}