com.threerings.io

Class Streamer

java.lang.Object

com.threerings.io.Streamer

Direct Known Subclasses:

BasicStreamers.BasicStreamer

public abstract class Streamer
extends Object

Handles the streaming of Streamable instances as well as a set of basic object types (see ObjectOutputStream). An instance of Streamer is created for each distinct class that implements Streamable. The Streamer reflects on the streamed class and caches the information necessary to efficiently read and write objects of the class in question.

Method Summary

Modifier and Type	Method and Description
abstract Object	createObject(ObjectInputStream in) Creates a blank object that can subsequently be read by this streamer.
static Class<?>	getCollectionClass(Class<?> clazz) If the specified class is not Streamable and is a Collection type, return the most specific supported Collection interface type; otherwise return null.
static Streamer	getStreamer(Class<?> target) Obtains a Streamer that can be used to read and write objects of the specified target class.
static Class<?>	getStreamerClass(Object object) Returns the class that should be used when streaming this object.
static boolean	isStreamable(Class<?> target) Returns true if the supplied target class can be streamed using a streamer.
abstract void	readObject(Object object, ObjectInputStream in, boolean useReader) Reads and populates the fields of the supplied object from the specified stream.
String	toString()
abstract void	writeObject(Object object, ObjectOutputStream out, boolean useWriter) Writes the supplied object to the specified stream.

Methods inherited from class java.lang.Object

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

Method Detail

isStreamable

public static boolean isStreamable(Class<?> target)

Returns true if the supplied target class can be streamed using a streamer.

getStreamerClass

public static Class<?> getStreamerClass(Object object)

Returns the class that should be used when streaming this object. In general that is the object's natural class, but for enum values, that might be its declaring class as enums use classes in a way that would otherwise pollute our id to class mapping space.

getCollectionClass

public static Class<?> getCollectionClass(Class<?> clazz)

If the specified class is not Streamable and is a Collection type, return the most specific supported Collection interface type; otherwise return null.

getStreamer

public static Streamer getStreamer(Class<?> target)
                            throws IOException

Obtains a Streamer that can be used to read and write objects of the specified target class. Streamer instances are shared among all ObjectInputStreams and ObjectOutputStreams.

Parameters:

target - the class that is desired to be streamed. This should be the result of a call to getStreamerClass(java.lang.Object) if the caller has an instance they wish to stream.

Throws:

IOException - when a streamer is requested for an object that does not implement Streamable and is not one of the basic object types (@see ObjectOutputStream).

writeObject

public abstract void writeObject(Object object,
                                 ObjectOutputStream out,
                                 boolean useWriter)
                          throws IOException

Writes the supplied object to the specified stream.

Parameters:

object - the instance to be written to the stream.

out - the stream to which to write the instance.

useWriter - whether or not to use the custom writeObject if one exists.

Throws:

IOException

createObject

public abstract Object createObject(ObjectInputStream in)
                             throws IOException,
                                    ClassNotFoundException

Creates a blank object that can subsequently be read by this streamer. Data may be read from the input stream as a result of this method (in the case of arrays, the length of the array must be read before creating the array).

Throws:

IOException

ClassNotFoundException

readObject

public abstract void readObject(Object object,
                                ObjectInputStream in,
                                boolean useReader)
                         throws IOException,
                                ClassNotFoundException

Reads and populates the fields of the supplied object from the specified stream.

Parameters:

object - the instance to be read from the stream.

in - the stream from which to read the instance.

useReader - whether or not to use the custom readObject if one exists.

Throws:

IOException

ClassNotFoundException

toString

public final String toString()

Overrides:

toString in class Object