org.infinispan.marshall
Interface Marshaller

All Known Implementing Classes:

AbstractMarshaller, JBossMarshaller, VersionAwareMarshaller

public interface Marshaller

A marshaller is a class that is able to marshall and unmarshall objects efficiently.

The reason why this is implemented specially in Infinispan rather than resorting to Java serialization or even the more efficient JBoss serialization is that a lot of efficiency can be gained when a majority of the serialization that occurs has to do with a small set of known types such as org.infinispan.transaction.GlobalTransaction or ReplicableCommand, and class type information can be replaced with simple magic numbers.

Unknown types (typically user data) falls back to JBoss serialization.

In addition, using a marshaller allows adding additional data to the byte stream, such as context class loader information on which class loader to use to deserialize the object stream, or versioning information to allow streams to interoperate between different versions of Infinispan (see VersionAwareMarshaller

This interface is used to marshall ReplicableCommands, their parameters and their response values.

The interface is also used by the CacheStore framework to efficiently serialize data to be persisted, as well as the StateTransferManager when serializing the cache for transferring state en-masse.

Since:

4.0

Author:

Manik Surtani, Galder Zamarreño

Method Summary

void	finishObjectInput(ObjectInput oi) Finish using the given ObjectInput.
void	finishObjectOutput(ObjectOutput oo) Finish using the given ObjectOutput.
Object	objectFromByteBuffer(byte[] buf)
Object	objectFromByteBuffer(byte[] buf, int offset, int length)
Object	objectFromInputStream(InputStream is)
Object	objectFromObjectStream(ObjectInput in) Unmarshalls an object from an ObjectInput
ByteBuffer	objectToBuffer(Object o) A method that returns an instance of ByteBuffer, which allows direct access to the byte array with minimal array copying
byte[]	objectToByteBuffer(Object obj)
void	objectToObjectStream(Object obj, ObjectOutput out) Marshalls an object to a given ObjectOutput
ObjectInput	startObjectInput(InputStream is, boolean isReentrant) Create and open a new ObjectInput for the given input stream.
ObjectOutput	startObjectOutput(OutputStream os, boolean isReentrant) Create and open an ObjectOutput instance for the given output stream.

Method Detail

startObjectOutput

ObjectOutput startObjectOutput(OutputStream os,
                               boolean isReentrant)
                               throws IOException

Create and open an ObjectOutput instance for the given output stream. This method should be used for opening data outputs when multiple objectToObjectStream() calls will be made before the stream is closed by calling finishObjectOutput().

This method also takes a boolean that represents whether this particular call to startObjectOutput() is reentrant or not. A call to startObjectOutput() should be marked reentrant whenever a 2nd or more calls to this method are made without having called finishObjectOutput() first.

To potentially speed up calling startObjectOutput multiple times in a non-reentrant way, i.e. startObjectOutput/finishObjectOutput...startObjectOutput/finishObjectOutput...etc, which is is the most common case, the Marshaller implementation could potentially use some mechanisms to speed up this startObjectOutput call.

On the other hand, when a call is reentrant, i.e. startObjectOutput/startObjectOutput(reentrant)...finishObjectOutput/finishObjectOutput, the Marshaller implementation might treat it differently. An example of reentrancy would be marshalling of MarshalledValue. When sending or storing a MarshalledValue, a call to startObjectOutput() would occur so that the stream is open and following, a 2nd call could occur so that MarshalledValue's raw byte array version is calculated and sent accross. This enables lazy deserialization on the receiver side which is performance gain. The Marshaller implementation could decide that it needs a separate ObjectOutput or similar for the 2nd call since it's aim is only to get the raw byte array version and the close finish with it.

Parameters:

os - output stream

isReentrant - whether the call is reentrant or not.

Returns:

ObjectOutput to write to

Throws:

IOException

finishObjectOutput

void finishObjectOutput(ObjectOutput oo)

Finish using the given ObjectOutput. After opening a ObjectOutput and calling objectToObjectStream() mutliple times, use this method to flush the data and close if necessary

Parameters:

oo - data output that finished using

objectToObjectStream

void objectToObjectStream(Object obj,
                          ObjectOutput out)
                          throws IOException

Marshalls an object to a given ObjectOutput

Parameters:

obj - object to marshall

out - stream to marshall to

Throws:

IOException

startObjectInput

ObjectInput startObjectInput(InputStream is,
                             boolean isReentrant)
                             throws IOException

Create and open a new ObjectInput for the given input stream. This method should be used for opening data inputs when multiple objectFromObjectStream() calls will be made before the stream is closed.

This method also takes a boolean that represents whether this particular call to startObjectInput() is reentrant or not. A call to startObjectInput() should be marked reentrant whenever a 2nd or more calls to this method are made without having called finishObjectInput() first.

To potentially speed up calling startObjectInput multiple times in a non-reentrant way, i.e. startObjectInput/finishObjectInput...startObjectInput/finishObjectInput...etc, which is is the most common case, the Marshaller implementation could potentially use some mechanisms to speed up this startObjectInput call.

Parameters:

is - input stream

isReentrant - whether the call is reentrant or not.

Returns:

ObjectInput to read from

Throws:

IOException

finishObjectInput

void finishObjectInput(ObjectInput oi)

Finish using the given ObjectInput. After opening a ObjectInput and calling objectFromObjectStream() mutliple times, use this method to flush the data and close if necessary

Parameters:

oi - data input that finished using

objectFromObjectStream

Object objectFromObjectStream(ObjectInput in)
                              throws IOException,
                                     ClassNotFoundException

Unmarshalls an object from an ObjectInput

Parameters:

in - stream to unmarshall from

Throws:

IOException

ClassNotFoundException

objectToBuffer

ByteBuffer objectToBuffer(Object o)
                          throws IOException

A method that returns an instance of ByteBuffer, which allows direct access to the byte array with minimal array copying

Parameters:

o - object to marshall

Returns:

a ByteBuffer

Throws:

Exception

IOException

objectFromByteBuffer

Object objectFromByteBuffer(byte[] buf,
                            int offset,
                            int length)
                            throws IOException,
                                   ClassNotFoundException

Throws:

IOException

ClassNotFoundException

objectToByteBuffer

byte[] objectToByteBuffer(Object obj)
                          throws IOException

Throws:

IOException

objectFromByteBuffer

Object objectFromByteBuffer(byte[] buf)
                            throws IOException,
                                   ClassNotFoundException

Throws:

IOException

ClassNotFoundException

objectFromInputStream

Object objectFromInputStream(InputStream is)
                             throws IOException,
                                    ClassNotFoundException

Throws:

IOException

ClassNotFoundException