org.aredis.io

Class OptiObjectOutputStream

java.lang.Object

java.io.OutputStream

java.io.ObjectOutputStream

org.aredis.io.OptiObjectOutputStream

All Implemented Interfaces:

Closeable, DataOutput, Flushable, ObjectOutput, ObjectStreamConstants, AutoCloseable

public class OptiObjectOutputStream
extends ObjectOutputStream

An ObjectOutputStream which optimizes storage by using a common ClassDescriptorStorage for maintaining the Class Descriptors for the class used in serialization. An index pointing to the central array of descriptors in the ClassDescriptorStorage is what is present in the stream.

The ClassDescriptorStorage is required to be up and working whenever a new class is encountered that is not present in the Local copy of the ClassDescriptors when writeObject method is called. If syncToStore field is set to true the ClassDescriptor storage is automatically updated with the local ClassDescriptors in that case. If the store attempt fails because the ClassDescriptors was updated in the store since it was read the operation is attempted again. If syncToStore is set to false then it is the responsibility of the user of this class to update the store with the new Class Descriptors available via the getUpdatedDescriptors method. If the update fails then the writeObject should be called again. Setting syncToStorage false is better since it makes fewer interactions with the store. However the user has to update the store when new Classes are encountered and the writeObject should be called again if the update fails. For retrying the writeObject the user has to either use a local Byte Array stream or use the mark/reset feature on a BufferedOutputStream. aredis uses false for syncToStorage.

This class is used by the OPTI_JAVA_HANDLER or aredis.

Author:

Suresh

Nested Class Summary

Nested classes/interfaces inherited from class java.io.ObjectOutputStream

ObjectOutputStream.PutField

Field Summary

Fields inherited from interface java.io.ObjectStreamConstants

baseWireHandle, PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, SC_BLOCK_DATA, SC_ENUM, SC_EXTERNALIZABLE, SC_SERIALIZABLE, SC_WRITE_METHOD, STREAM_MAGIC, STREAM_VERSION, SUBCLASS_IMPLEMENTATION_PERMISSION, SUBSTITUTION_PERMISSION, TC_ARRAY, TC_BASE, TC_BLOCKDATA, TC_BLOCKDATALONG, TC_CLASS, TC_CLASSDESC, TC_ENDBLOCKDATA, TC_ENUM, TC_EXCEPTION, TC_LONGSTRING, TC_MAX, TC_NULL, TC_OBJECT, TC_PROXYCLASSDESC, TC_REFERENCE, TC_RESET, TC_STRING

Constructor Summary

Constructors

Constructor and Description
OptiObjectOutputStream(OutputStream out, ClassDescriptorStorage pdescriptorsStorage) Creates an OptiObjectOutputStream with syncToStorate as true.
OptiObjectOutputStream(OutputStream out, ClassDescriptorStorage pdescriptorsStorage, boolean psyncToStorage) Creates an OptiObjectOutputStream.

Method Summary

Methods

Modifier and Type	Method and Description
ClassDescriptors	getUpdatedDescriptors() Gets the updated descriptors.
boolean	isSyncToStorage() Checks whether syncToStorage is enabled.
protected void	writeClassDescriptor(ObjectStreamClass desc)

Methods inherited from class java.io.ObjectOutputStream

annotateClass, annotateProxyClass, close, defaultWriteObject, drain, enableReplaceObject, flush, putFields, replaceObject, reset, useProtocolVersion, write, write, write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFields, writeFloat, writeInt, writeLong, writeObject, writeObjectOverride, writeShort, writeStreamHeader, writeUnshared, writeUTF

Methods inherited from class java.lang.Object

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

Constructor Detail

OptiObjectOutputStream

public OptiObjectOutputStream(OutputStream out,
                      ClassDescriptorStorage pdescriptorsStorage,
                      boolean psyncToStorage)
                       throws IOException

Creates an OptiObjectOutputStream. When syncToStorage is set to true

Parameters:

out - Underlying OutputStream

pdescriptorsStorage - Whether to sync the local class descriptors to store whenever a new class is encountered in writeObject. This is simpler to use.

psyncToStorage - Class Descriptors store to use

Throws:

IOException - In case of IO error

OptiObjectOutputStream

public OptiObjectOutputStream(OutputStream out,
                      ClassDescriptorStorage pdescriptorsStorage)
                       throws IOException

Creates an OptiObjectOutputStream with syncToStorate as true.

Parameters:

out - Underlying OutputStream

Throws:

IOException - In case of IO error

Method Detail

writeClassDescriptor

protected void writeClassDescriptor(ObjectStreamClass desc)
                             throws IOException

Overrides:

writeClassDescriptor in class ObjectOutputStream

Throws:

IOException

getUpdatedDescriptors

public ClassDescriptors getUpdatedDescriptors()

Gets the updated descriptors. If this returns a non null value, the user should try to save the returned ClassDescriptors to the ClassDescriptorStorage. If the storage fails the writeObject should be tried again. This method always returns false if syncToStorage is set to true.

Returns:

Updated ClassDescriptors

isSyncToStorage

public boolean isSyncToStorage()

Checks whether syncToStorage is enabled.

Returns:

syncToStorage