org.planx.io
Class PolymorphicStreamer<T>

java.lang.Object
  org.planx.io.PolymorphicStreamer<T>

All Implemented Interfaces:

Streamer<T>

public class PolymorphicStreamer<T>
extends Object
implements Streamer<T>

A polymorphic Streamer that can handle multiple datatypes. A datatype is registered using addStreamer(byte, java.lang.Class, org.planx.io.Streamer). Each datatype must be given a unique id that is used to differentiate between the datatypes when reading data. When writing data the class of the object is examined. If multiple Streamers are registered which can all handle a specific subclass, it is unspecified which Streamer is used. The most specific Streamer is not chosen. Thus, in general, registering a Streamer with a super class of a class of another registered Streamer should be avoided. Use the most specific class possible when registering Streamers.

Streamers used with the PolymorphicStreamer must always return null in their toStream method.

Author:

Thomas Ambus

Constructor Summary

PolymorphicStreamer()

Method Summary

<E extends T> void	addStreamer(byte id, Class<? extends E> cls, Streamer<E> streamer)
T	fromStream(DataInput in) Reads an object of class E from the data source.
void	toStream(DataOutput out, T obj) Writes the internal state of the object to the data source in a format that can later be read by the same Streamer using the fromStream method.

Methods inherited from class java.lang.Object

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

Constructor Detail

PolymorphicStreamer

public PolymorphicStreamer()

Method Detail

addStreamer

public <E extends T> void addStreamer(byte id,
                                      Class<? extends E> cls,
                                      Streamer<E> streamer)

toStream

public void toStream(DataOutput out,
                     T obj)
              throws IOException

Description copied from interface: Streamer

Writes the internal state of the object to the data source in a format that can later be read by the same Streamer using the fromStream method.

Specified by:

toStream in interface Streamer<T>

Throws:

IOException

fromStream

public T fromStream(DataInput in)
             throws IOException

Description copied from interface: Streamer

Reads an object of class E from the data source.

Specified by:

fromStream in interface Streamer<T>

Throws:

IOException