Package org.apache.hadoop.util

Class GenericsUtil

java.lang.Object

org.apache.hadoop.util.GenericsUtil

@Private
@Unstable
public class GenericsUtil
extends java.lang.Object

Contains utility methods for dealing with Java Generics.

Constructor Summary

Constructors

Constructor	Description
GenericsUtil()

Method Summary

Modifier and Type	Method	Description
static <T> java.lang.Class<T>	getClass(T t)	Returns the Class object (of type Class<T>) of the argument of type T.
static boolean	isLog4jLogger(java.lang.Class<?> clazz)	Determine whether the log of clazz is Log4j implementation.
static boolean	isLog4jLogger(java.lang.String logger)	Determine whether the log of the given logger is of Log4J implementation.
static <T> T[]	toArray(java.lang.Class<T> c, java.util.List<T> list)	Converts the given List<T> to a an array of T[].
static <T> T[]	toArray(java.util.List<T> list)	Converts the given List<T> to a an array of T[].

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericsUtil

public GenericsUtil()

Method Detail

getClass

public static <T> java.lang.Class<T> getClass(T t)

Returns the Class object (of type Class<T>) of the argument of type T.

Type Parameters:

T - The type of the argument

Parameters:

t - the object to get it class

Returns:

Class<T>

toArray

public static <T> T[] toArray(java.lang.Class<T> c,
                              java.util.List<T> list)

Converts the given List<T> to a an array of T[].

Type Parameters:

T - Generics Type T.

Parameters:

c - the Class object of the items in the list

list - the list to convert

Returns:

T Array.

toArray

public static <T> T[] toArray(java.util.List<T> list)

Converts the given List<T> to a an array of T[].

Type Parameters:

T - Generics Type T.

Parameters:

list - the list to convert

Returns:

T Array.

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the list is empty. Use toArray(Class, List) if the list may be empty.

isLog4jLogger

public static boolean isLog4jLogger(java.lang.Class<?> clazz)

Determine whether the log of clazz is Log4j implementation.

Parameters:

clazz - a class to be determined

Returns:

true if the log of clazz is Log4j implementation.

isLog4jLogger

public static boolean isLog4jLogger(java.lang.String logger)

Determine whether the log of the given logger is of Log4J implementation.

Parameters:

logger - the logger name, usually class name as string.

Returns:

true if the logger uses Log4J implementation.