messif.objects.nio
Class MultiClassSerializator<T>

java.lang.Object
  messif.objects.nio.BinarySerializator
      messif.objects.nio.MultiClassSerializator<T>

Type Parameters:

T - default class used when reading serialized object

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

CachingSerializator

public class MultiClassSerializator<T>
extends BinarySerializator
implements java.io.Serializable

This implements a full-featured BinarySerializator which works on all classes. There is a cost of the class name and constructor/factory method lookup when the objects are deserialized for other than the default class. This serializator checks the serialUIDs of the default class for changes.

See Also:

Serialized Form

Field Summary

protected static byte	CLASSNAME_SERIALIZATION Constant indicating that the name of the class is written in the stream
protected java.lang.reflect.Constructor<?>	constructor The cached constructor for the default class
protected java.lang.Class<? extends T>	defaultClass The first class in the predefinedClasses is used as default
protected static byte	DEFAULTCLASS_SERIALIZATION Constant indicating that the default class is written in the stream
protected java.lang.reflect.Method	factoryMethod The cached factory method for the default class
protected static byte	JAVA_SERIALIZATION Constant indicating that the standard Java serialization is used

Fields inherited from class messif.objects.nio.BinarySerializator

log

Constructor Summary

MultiClassSerializator(java.lang.Class<? extends T> defaultClass)
Creates a new instance of MultiClassSerializator.

Method Summary

boolean	equals(java.lang.Object obj) Indicates whether some other object is "equal to" this serializator.
protected int	getBinarySize(BinarySerializable object) Returns the size of the binary-serialized object in bytes.
protected int	getClassIndex(BinarySerializable object) Returns the index of the predefined class for this object.
protected java.lang.reflect.Constructor<?>	getConstructor(byte flag, java.lang.Class<?> objectClass) Returns a constructor for the specified flag and object class.
java.lang.Class<? extends T>	getDefaultClass() Returns a default class that is used for deserialization when a class is not specified.
protected java.lang.reflect.Method	getFactoryMethod(byte flag, java.lang.Class<?> objectClass) Returns a factory method for the specified flag and object class.
int	hashCode() Returns a hash code value for this serializator.
T	readObject(BinaryInput input) Reads an instance from the input using this serializator.
protected <E> E	readObjectImpl(BinaryInput input, java.lang.Class<E> expectedClass) Reads an instance using the proper constructor/factory method.
protected int	write(BinaryOutput output, BinarySerializable object) Writes object to this output buffer using binary serialization.

Methods inherited from class messif.objects.nio.BinarySerializator

getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getBinarySize, getNativeSerializableConstructor, getNativeSerializableFactoryMethod, getSerialVersionUID, getSerialVersionUIDHash, readBoolean, readBooleanArray, readByte, readByteArray, readChar, readCharArray, readDouble, readDoubleArray, readFloat, readFloatArray, readInt, readIntArray, readLong, readLongArray, readObject, readObject, readObjectSize, readShort, readShortArray, readString, skipObject, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write

Methods inherited from class java.lang.Object

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

Field Detail

JAVA_SERIALIZATION

protected static final byte JAVA_SERIALIZATION

Constant indicating that the standard Java serialization is used

See Also:

Constant Field Values

DEFAULTCLASS_SERIALIZATION

protected static final byte DEFAULTCLASS_SERIALIZATION

Constant indicating that the default class is written in the stream

See Also:

Constant Field Values

CLASSNAME_SERIALIZATION

protected static final byte CLASSNAME_SERIALIZATION

Constant indicating that the name of the class is written in the stream

See Also:

Constant Field Values

defaultClass

protected final java.lang.Class<? extends T> defaultClass

The first class in the predefinedClasses is used as default

constructor

protected final transient java.lang.reflect.Constructor<?> constructor

The cached constructor for the default class

factoryMethod

protected final transient java.lang.reflect.Method factoryMethod

The cached factory method for the default class

Constructor Detail

MultiClassSerializator

public MultiClassSerializator(java.lang.Class<? extends T> defaultClass)
                       throws java.lang.IllegalArgumentException

Creates a new instance of MultiClassSerializator. If the defaultClass implements the BinarySerializable interface, the constructor/factory method is extracted for deserializing. Otherwise a standard Java serialization will be used. The constructor/factory method of the defaultClass is cached.

Parameters:

defaultClass - the default class that is used for deserialization when a class is not specified

Throws:

java.lang.IllegalArgumentException - if there is an invalid value in predefinedClasses

Method Detail

readObject

public T readObject(BinaryInput input)
             throws java.io.IOException,
                    java.lang.IllegalArgumentException

Reads an instance from the input using this serializator. The default class that is expected to be in the buffer.

Parameters:

input - the buffer to read the instance from

Returns:

an instance of the deserialized object

Throws:

java.io.IOException - if there was an I/O error

java.lang.IllegalArgumentException - if the constructor or the factory method has a wrong prototype

getBinarySize

protected int getBinarySize(BinarySerializable object)
                     throws java.lang.IllegalArgumentException

Returns the size of the binary-serialized object in bytes.

Specified by:

getBinarySize in class BinarySerializator

Parameters:

object - the object to get the size for

Returns:

the size of the binary-serialized object

Throws:

java.lang.IllegalArgumentException - if there was an error using Java standard serialization on the object

write

protected int write(BinaryOutput output,
                    BinarySerializable object)
             throws java.io.IOException

Description copied from class: BinarySerializator

Writes object to this output buffer using binary serialization. The following rules must hold:

• this method must write to the buffer exactly the number of bytes returned by BinarySerializator.getBinarySize(BinarySerializable)
• the readObject method must read the serialized data exactly as written by this method

Specified by:

write in class BinarySerializator

Parameters:

output - the buffer to write the object to

object - the object to write

Returns:

the number of bytes actually written

Throws:

java.io.IOException - if there was an error using flushChannel

readObjectImpl

protected <E> E readObjectImpl(BinaryInput input,
                               java.lang.Class<E> expectedClass)
                    throws java.io.IOException,
                           java.lang.IllegalArgumentException

Reads an instance using the proper constructor/factory method. First, a byte flag resolving the type of deserialization is read. If the flag indicates that the class name is stored in the input, it is read and checked. Then, the constructor and/or factory method is retrieved via getConstructor(byte, java.lang.Class) and getFactoryMethod(byte, java.lang.Class). Finally, the object is deserialized using the constructor, the factory method or standard Java serialization.

Specified by:

readObjectImpl in class BinarySerializator

Type Parameters:

E - the class that is expected to be in the input

Parameters:

input - the buffer to read the instance from

expectedClass - the class that is expected to be in the buffer

Returns:

an instance of the deserialized object

Throws:

java.io.IOException - if there was an I/O error

java.lang.IllegalArgumentException - if there was a problem getting a valid constructor/factory method

getConstructor

protected java.lang.reflect.Constructor<?> getConstructor(byte flag,
                                                          java.lang.Class<?> objectClass)
                                                   throws java.lang.IllegalArgumentException

Returns a constructor for the specified flag and object class.

Parameters:

flag - the type of deserialization (see constants)

objectClass - the class that is expected to be in the stream

Returns:

a constructor for the specified flag and object class

Throws:

java.lang.IllegalArgumentException - if there was a problem getting the constructor

getFactoryMethod

protected java.lang.reflect.Method getFactoryMethod(byte flag,
                                                    java.lang.Class<?> objectClass)
                                             throws java.lang.IllegalArgumentException

Returns a factory method for the specified flag and object class.

Parameters:

flag - the type of deserialization (see constants)

objectClass - the class that is expected to be in the stream

Returns:

a constructor for the specified flag and object class

Throws:

java.lang.IllegalArgumentException - if there was a problem getting the factory method

getClassIndex

protected int getClassIndex(BinarySerializable object)

Returns the index of the predefined class for this object.

Parameters:

object - the object whose class is looked up

Returns:

the index of the predefined class for this object

getDefaultClass

public java.lang.Class<? extends T> getDefaultClass()

Returns a default class that is used for deserialization when a class is not specified.

Returns:

a default class that is used for deserialization

hashCode

public int hashCode()

Returns a hash code value for this serializator. It is based on the serialVersionUID of the defaultClass.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code value for this serializator

equals

public boolean equals(java.lang.Object obj)

Indicates whether some other object is "equal to" this serializator. In particular, the other object must be MultiClassSerializator and have the same default class.

Overrides:

equals in class java.lang.Object

Parameters:

obj - the reference object with which to compare

Returns:

true if this serializator is the same as the obj argument; false otherwise.