org.apache.hadoop.util

Class ReflectionUtils

java.lang.Object

org.apache.hadoop.util.ReflectionUtils

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public class ReflectionUtils
extends Object

General reflection utils. This is a copy of ReflectionUtils in hadoop-common-2.3.0.jar. This copy has been modified not to cache constructors in method newInstance(Class, Configuration). Caching of constructors causes PluginClassLoaders to be retained when running that use plugins, thus causing OOM.

Constructor Summary

Constructors

Constructor and Description
ReflectionUtils()

Method Summary

Modifier and Type	Method and Description
static void	cloneWritableInto(org.apache.hadoop.io.Writable dst, org.apache.hadoop.io.Writable src) Deprecated.
static <T> T	copy(org.apache.hadoop.conf.Configuration conf, T src, T dst) Make a copy of the writable object using serialization to a buffer
static <T> Class<T>	getClass(T o) Return the correctly-typed Class of the given object.
static List<Field>	getDeclaredFieldsIncludingInherited(Class<?> clazz) Gets all the declared fields of a class including fields declared in superclasses.
static List<Method>	getDeclaredMethodsIncludingInherited(Class<?> clazz) Gets all the declared methods of a class including methods declared in superclasses.
static void	logThreadInfo(org.apache.commons.logging.Log log, String title, long minInterval) Log the current thread stacks at INFO level.
static <T> T	newInstance(Class<T> theClass, org.apache.hadoop.conf.Configuration conf) Create an object for the given class and initialize it from conf
static void	printThreadInfo(PrintWriter stream, String title) Print all of the thread's information and stack traces.
static void	setConf(Object theObject, org.apache.hadoop.conf.Configuration conf) Check and set 'configuration' if necessary.
static void	setContentionTracing(boolean val)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReflectionUtils

public ReflectionUtils()

Method Detail

setConf

public static void setConf(Object theObject,
                           org.apache.hadoop.conf.Configuration conf)

Check and set 'configuration' if necessary.

Parameters:

theObject - object for which to set configuration

conf - Configuration

newInstance

public static <T> T newInstance(Class<T> theClass,
                                org.apache.hadoop.conf.Configuration conf)

Create an object for the given class and initialize it from conf

Parameters:

theClass - class of which an object is created

conf - Configuration

Returns:

a new object

setContentionTracing

public static void setContentionTracing(boolean val)

printThreadInfo

public static void printThreadInfo(PrintWriter stream,
                                   String title)

Print all of the thread's information and stack traces.

Parameters:

stream - the stream to

title - a string title for the stack trace

logThreadInfo

public static void logThreadInfo(org.apache.commons.logging.Log log,
                                 String title,
                                 long minInterval)

Log the current thread stacks at INFO level.

Parameters:

log - the logger that logs the stack trace

title - a descriptive title for the call stacks

minInterval - the minimum time from the last

getClass

public static <T> Class<T> getClass(T o)

Return the correctly-typed Class of the given object.

Parameters:

o - object whose correctly-typed Class is to be obtained

Returns:

the correctly typed Class of the given object.

copy

public static <T> T copy(org.apache.hadoop.conf.Configuration conf,
                         T src,
                         T dst)
                  throws IOException

Make a copy of the writable object using serialization to a buffer

Parameters:

src - the object to copy from

dst - the object to copy into, which is destroyed

Returns:

dst param (the copy)

Throws:

IOException

cloneWritableInto

@Deprecated
public static void cloneWritableInto(org.apache.hadoop.io.Writable dst,
                                                 org.apache.hadoop.io.Writable src)
                                          throws IOException

Deprecated.

Throws:

IOException

getDeclaredFieldsIncludingInherited

public static List<Field> getDeclaredFieldsIncludingInherited(Class<?> clazz)

Gets all the declared fields of a class including fields declared in superclasses.

getDeclaredMethodsIncludingInherited

public static List<Method> getDeclaredMethodsIncludingInherited(Class<?> clazz)

Gets all the declared methods of a class including methods declared in superclasses.