org.apache.hadoop.io
Class DefaultStringifier<T>

java.lang.Object
  org.apache.hadoop.io.DefaultStringifier<T>

Type Parameters:

T - the class of the objects to stringify

All Implemented Interfaces:

Closeable, Stringifier<T>

public class DefaultStringifier<T>
extends Object
implements Stringifier<T>

DefaultStringifier is the default implementation of the Stringifier interface which stringifies the objects using base64 encoding of the serialized version of the objects. The Serializer and Deserializer are obtained from the SerializationFactory.
DefaultStringifier offers convenience methods to store/load objects to/from the configuration.

Constructor Summary

DefaultStringifier(Configuration conf, Class<T> c)

Method Summary

void	close() Closes this object.
T	fromString(String str) Restores the object from its string representation.
static <K> K	load(Configuration conf, String keyName, Class<K> itemClass) Restores the object from the configuration.
static <K> K[]	loadArray(Configuration conf, String keyName, Class<K> itemClass) Restores the array of objects from the configuration.
static <K> void	store(Configuration conf, K item, String keyName) Stores the item in the configuration with the given keyName.
static <K> void	storeArray(Configuration conf, K[] items, String keyName) Stores the array of items in the configuration with the given keyName.
String	toString(T obj) Converts the object to a string representation

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultStringifier

public DefaultStringifier(Configuration conf,
                          Class<T> c)

Method Detail

fromString

public T fromString(String str)
             throws IOException

Description copied from interface: Stringifier

Restores the object from its string representation.

Specified by:

fromString in interface Stringifier<T>

Parameters:

str - the string representation of the object

Returns:

restored object

Throws:

IOException - if the object cannot be restored

toString

public String toString(T obj)
                throws IOException

Description copied from interface: Stringifier

Converts the object to a string representation

Specified by:

toString in interface Stringifier<T>

Parameters:

obj - the object to convert

Returns:

the string representation of the object

Throws:

IOException - if the object cannot be converted

close

public void close()
           throws IOException

Description copied from interface: Stringifier

Closes this object.

Specified by:

close in interface Closeable

Specified by:

close in interface Stringifier<T>

Throws:

IOException - if an I/O error occurs

store

public static <K> void store(Configuration conf,
                             K item,
                             String keyName)
                  throws IOException

Stores the item in the configuration with the given keyName.

Type Parameters:

K - the class of the item

Parameters:

conf - the configuration to store

item - the object to be stored

keyName - the name of the key to use

Throws:

IOException - : forwards Exceptions from the underlying Serialization classes.

load

public static <K> K load(Configuration conf,
                         String keyName,
                         Class<K> itemClass)
              throws IOException

Restores the object from the configuration.

Type Parameters:

K - the class of the item

Parameters:

conf - the configuration to use

keyName - the name of the key to use

itemClass - the class of the item

Returns:

restored object

Throws:

IOException - : forwards Exceptions from the underlying Serialization classes.

storeArray

public static <K> void storeArray(Configuration conf,
                                  K[] items,
                                  String keyName)
                       throws IOException

Stores the array of items in the configuration with the given keyName.

Type Parameters:

K - the class of the item

Parameters:

conf - the configuration to use

items - the objects to be stored

keyName - the name of the key to use

Throws:

IndexOutOfBoundsException - if the items array is empty

IOException - : forwards Exceptions from the underlying Serialization classes.

loadArray

public static <K> K[] loadArray(Configuration conf,
                                String keyName,
                                Class<K> itemClass)
                     throws IOException

Restores the array of objects from the configuration.

Type Parameters:

K - the class of the item

Parameters:

conf - the configuration to use

keyName - the name of the key to use

itemClass - the class of the item

Returns:

restored object

Throws:

IOException - : forwards Exceptions from the underlying Serialization classes.