/**
* 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.hadoop.util;
import java.lang.reflect.Constructor;
import java.io.*;
import java.lang.management.*;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.mapred.*;
/**
* General reflection utils
*/
public class ReflectionUtils {
private static final Class[] emptyArray = new Class[]{};
/**
* Cache of constructors for each class. Pins the classes so they
* can't be garbage collected until ReflectionUtils can be collected.
*/
private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE =
new ConcurrentHashMap<Class<?>, Constructor<?>>();
/**
* Check and set 'configuration' if necessary.
*
* @param theObject object for which to set configuration
* @param conf Configuration
*/
public static void setConf(Object theObject, Configuration conf) {
if (conf != null) {
if (theObject instanceof Configurable) {
((Configurable) theObject).setConf(conf);
}
if (conf instanceof JobConf &&
theObject instanceof JobConfigurable) {
((JobConfigurable)theObject).configure((JobConf) conf);
}
}
}
/** Create an object for the given class and initialize it from conf
*
* @param theClass class of which an object is created
* @param conf Configuration
* @return a new object
*/
@SuppressWarnings("unchecked")
public static <T> T newInstance(Class<T> theClass, Configuration conf) {
T result;
try {
Constructor<T> meth = (Constructor<T>) CONSTRUCTOR_CACHE.get(theClass);
if (meth == null) {
meth = theClass.getDeclaredConstructor(emptyArray);
meth.setAccessible(true);
CONSTRUCTOR_CACHE.put(theClass, meth);
}
result = meth.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
setConf(result, conf);
return result;
}
static private ThreadMXBean threadBean =
ManagementFactory.getThreadMXBean();
public static void setContentionTracing(boolean val) {
threadBean.setThreadContentionMonitoringEnabled(val);
}
private static String getTaskName(long id, String name) {
if (name == null) {
return Long.toString(id);
}
return id + " (" + name + ")";
}
/**
* Print all of the thread's information and stack traces.
*
* @param stream the stream to
* @param title a string title for the stack trace
*/
public static void printThreadInfo(PrintWriter stream,
String title) {
final int STACK_DEPTH = 20;
boolean contention = threadBean.isThreadContentionMonitoringEnabled();
long[] threadIds = threadBean.getAllThreadIds();
stream.println("Process Thread Dump: " + title);
stream.println(threadIds.length + " active threads");
for (long tid: threadIds) {
ThreadInfo info = threadBean.getThreadInfo(tid, STACK_DEPTH);
if (info == null) {
stream.println(" Inactive");
continue;
}
stream.println("Thread " +
getTaskName(info.getThreadId(),
info.getThreadName()) + ":");
Thread.State state = info.getThreadState();
stream.println(" State: " + state);
stream.println(" Blocked count: " + info.getBlockedCount());
stream.println(" Waited count: " + info.getWaitedCount());
if (contention) {
stream.println(" Blocked time: " + info.getBlockedTime());
stream.println(" Waited time: " + info.getWaitedTime());
}
if (state == Thread.State.WAITING) {
stream.println(" Waiting on " + info.getLockName());
} else if (state == Thread.State.BLOCKED) {
stream.println(" Blocked on " + info.getLockName());
stream.println(" Blocked by " +
getTaskName(info.getLockOwnerId(),
info.getLockOwnerName()));
}
stream.println(" Stack:");
for (StackTraceElement frame: info.getStackTrace()) {
stream.println(" " + frame.toString());
}
}
stream.flush();
}
private static long previousLogTime = 0;
/**
* Log the current thread stacks at INFO level.
* @param log the logger that logs the stack trace
* @param title a descriptive title for the call stacks
* @param minInterval the minimum time from the last
*/
public static void logThreadInfo(Log log,
String title,
long minInterval) {
boolean dumpStack = false;
if (log.isInfoEnabled()) {
synchronized (ReflectionUtils.class) {
long now = System.currentTimeMillis();
if (now - previousLogTime >= minInterval * 1000) {
previousLogTime = now;
dumpStack = true;
}
}
if (dumpStack) {
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
printThreadInfo(new PrintWriter(buffer), title);
log.info(buffer.toString());
}
}
}
/**
* Return the correctly-typed {@link Class} of the given object.
*
* @param o object whose correctly-typed <code>Class</code> is to be obtained
* @return the correctly typed <code>Class</code> of the given object.
*/
@SuppressWarnings("unchecked")
public static <T> Class<T> getClass(T o) {
return (Class<T>)o.getClass();
}
// methods to support testing
static void clearCache() {
CONSTRUCTOR_CACHE.clear();
}
static int getCacheSize() {
return CONSTRUCTOR_CACHE.size();
}
}