cascading.tuple.hadoop

Annotation Type SerializationToken

@Retention(value=RUNTIME)
 @Target(value=TYPE)
public @interface SerializationToken

Annotation SerializationToken enables TupleInputStream and TupleOutputStream to substitute Integer values for a class name when writing out nested objects inside a Tuple.

To use, add this annotation to any custom Hadoop Serialization implementation.

For example:

 @SerializationToken(tokens={222, 223}, classNames = {"example.PersonObject", "example.SiteObject"})
 public class MySerialization implements org.apache.hadoop.io.serializer.Serialization
 {
 public MySerialization()
 {
 ...
 }
 ...
 }
 

The SerializationToken annotation allows for multiple token to className mappings, since a Serialization implementation may Serialization.accept(Class) more than one class.

Note that the token integer value must be 128 or greater to save room for internal types.

See Also:

TupleInputStream, TupleOutputStream, TupleSerialization

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
java.lang.String[]	classNames
int[]	tokens

Element Detail

tokens

public abstract int[] tokens

classNames

public abstract java.lang.String[] classNames