/*
* 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.wicket.util.lang;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.wicket.util.string.interpolator.MapVariableInterpolator;
import org.slf4j.Logger;
/**
* A utility class for dealing with {@link Thread}s.
*/
public class Threads
{
private static final String FORMAT = "\"${name}\"${isDaemon} prio=${priority} tid=${threadIdDec} state=${state} ";
private Threads()
{
}
/**
* Creates a dump of all the threads' state and stack traces similar to what JVM produces when
* signal SIGQUIT is send to the process on Unix machine.
* <p>
* Note: This is a best effort to dump as much information as possible because the Java API
* doesn't provide means to get all the information that is produced by jstack program for
* example.
* </p>
*
* @param logger
* the logger where the collected information will be written
*/
public static void dumpAllThreads(Logger logger)
{
Args.notNull(logger, "logger");
if (!logger.isWarnEnabled())
{
return;
}
RuntimeMXBean runtimeMXBean = ManagementFactory.getRuntimeMXBean();
StringBuilder dump = new StringBuilder();
dump.append("Full thread dump ")
.append(runtimeMXBean.getVmName())
.append('(')
.append(runtimeMXBean.getVmVersion())
.append(')');
logger.warn(dump.toString());
Map<Thread, StackTraceElement[]> allStackTraces = Thread.getAllStackTraces();
for (Entry<Thread, StackTraceElement[]> entry : allStackTraces.entrySet())
{
dumpSingleThread(logger, entry.getKey(), entry.getValue());
}
}
/**
* Creates a dump of the threads' state and stack traces similar to the one that the JVM
* produces when signal SIGQUIT is send to the process on Unix machine.
* <p>
* Note: This is a best effort to dump as much information as possible because the Java API
* doesn't provide means to get all the information that is produced by jstack program for
* example.
* </p>
*
* @param logger
* the logger where the collected information will be written
* @param thread
* the thread to dump
*/
public static void dumpSingleThread(Logger logger, Thread thread)
{
Args.notNull(logger, "logger");
if (!logger.isWarnEnabled())
{
return;
}
dumpSingleThread(logger, thread, thread.getStackTrace());
}
private static void dumpSingleThread(Logger logger, Thread thread, StackTraceElement[] trace)
{
Map<CharSequence, Object> variables = new HashMap<>();
variables.put("name", thread.getName());
variables.put("isDaemon", thread.isDaemon() ? " daemon" : "");
variables.put("priority", thread.getPriority());
variables.put("threadIdDec", thread.getId());
variables.put("state", thread.getState());
ThreadDump throwable = new ThreadDump();
throwable.setStackTrace(trace);
logger.warn(MapVariableInterpolator.interpolate(FORMAT, variables), throwable);
}
/**
* An exception used to hold the stacktrace of a thread.
*/
private static class ThreadDump extends RuntimeException
{
private static final long serialVersionUID = 1L;
/**
* @see java.lang.Throwable#fillInStackTrace()
*/
@Override
public synchronized Throwable fillInStackTrace()
{
// don't waste time to load the stack of the current thread
return null;
}
}
}