ObjectStreamField

AI-generated Key Takeaways

• ObjectStreamField describes a Serializable field from a Serializable class and is used to declare Serializable fields of a class.

• It provides methods to get the name, type, offset, and other information about the field.

• Two constructors allow creation of ObjectStreamField with field name and type, with an optional unshared flag for customized serialization and deserialization.

• ObjectStreamField implements Comparable to allow comparison with other ObjectStreamField instances.

• isUnshared() indicates if the field is serialized and deserialized using writeUnshared/readUnshared methods.

public class ObjectStreamField extends Object
implements Comparable<Object>

A description of a Serializable field from a Serializable class. An array of ObjectStreamFields is used to declare the Serializable fields of a class.

See Also

• ObjectStreamClass

Public Constructor Summary

	ObjectStreamField(String name, Class<?> type) Create a Serializable field with the specified type.
	ObjectStreamField(String name, Class<?> type, boolean unshared) Creates an ObjectStreamField representing a serializable field with the given name and type.

Public Method Summary

int	compareTo(Object obj) Compare this field with another ObjectStreamField.
String	getName() Get the name of this field.
int	getOffset() Offset of field within instance data.
Class<?>	getType() Get the type of the field.
char	getTypeCode() Returns character encoding of field type.
String	getTypeString() Return the JVM type signature.
boolean	isPrimitive() Return true if this field has a primitive type.
boolean	isUnshared() Returns boolean value indicating whether or not the serializable field represented by this ObjectStreamField instance is unshared.
String	toString() Return a string that describes this field.

Protected Method Summary

void	setOffset(int offset) Offset within instance data.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.lang.Comparable

abstract int

compareTo(Object o) Compares this object with the specified object for order.

Public Constructors

public ObjectStreamField (String name, Class<?> type)

Create a Serializable field with the specified type. This field should be documented with a serialField tag.

Parameters

name	the name of the serializable field
type	the Class object of the serializable field

public ObjectStreamField (String name, Class<?> type, boolean unshared)

Creates an ObjectStreamField representing a serializable field with the given name and type. If unshared is false, values of the represented field are serialized and deserialized in the default manner--if the field is non-primitive, object values are serialized and deserialized as if they had been written and read by calls to writeObject and readObject. If unshared is true, values of the represented field are serialized and deserialized as if they had been written and read by calls to writeUnshared and readUnshared.

Parameters

name	field name
type	field type
unshared	if false, write/read field values in the same manner as writeObject/readObject; if true, write/read in the same manner as writeUnshared/readUnshared

Public Methods

public int compareTo (Object obj)

Compare this field with another ObjectStreamField. Return -1 if this is smaller, 0 if equal, 1 if greater. Types that are primitives are "smaller" than object types. If equal, the field names are compared.

Parameters

obj

public String getName ()

Get the name of this field.

Returns

• a String representing the name of the serializable field

public int getOffset ()

Offset of field within instance data.

Returns

• the offset of this field

See Also

• setOffset(int)

public Class<?> getType ()

Get the type of the field. If the type is non-primitive and this ObjectStreamField was obtained from a deserialized ObjectStreamClass instance, then Object.class is returned. Otherwise, the Class object for the type of the field is returned.

Returns

• a Class object representing the type of the serializable field

public char getTypeCode ()

Returns character encoding of field type. The encoding is as follows:

 B            byte
 C            char
 D            double
 F            float
 I            int
 J            long
 L            class or interface
 S            short
 Z            boolean
 [            array
 

Returns

• the typecode of the serializable field

public String getTypeString ()

Return the JVM type signature.

Returns

• null if this field has a primitive type.

public boolean isPrimitive ()

Return true if this field has a primitive type.

Returns

• true if and only if this field corresponds to a primitive type

public boolean isUnshared ()

Returns boolean value indicating whether or not the serializable field represented by this ObjectStreamField instance is unshared.

Returns

• true if this field is unshared

public String toString ()

Return a string that describes this field.

Returns

• a printable representation of this object.

Protected Methods

protected void setOffset (int offset)

Offset within instance data.

Parameters

offset	the offset of the field

See Also

• getOffset()