ObjectInputStream.GetField

AI-generated Key Takeaways

• ObjectInputStream.GetField provides access to persistent fields read from an input stream during deserialization.

• It offers methods to retrieve the values of various primitive and object type fields by name, using default values if the field is not present in the stream.

• The defaulted method checks if a named field is not present (defaulted) in the stream.

• getObjectStreamClass returns the ObjectStreamClass descriptor associated with the stream's fields.

public static abstract class ObjectInputStream.GetField extends Object

Provide access to the persistent fields read from the input stream.

Public Constructor Summary

GetField()

Public Method Summary

abstract boolean	defaulted(String name) Return true if the named field is defaulted and has no value in this stream.
abstract boolean	get(String name, boolean val) Get the value of the named boolean field from the persistent field.
abstract byte	get(String name, byte val) Get the value of the named byte field from the persistent field.
abstract short	get(String name, short val) Get the value of the named short field from the persistent field.
abstract char	get(String name, char val) Get the value of the named char field from the persistent field.
abstract int	get(String name, int val) Get the value of the named int field from the persistent field.
abstract float	get(String name, float val) Get the value of the named float field from the persistent field.
abstract double	get(String name, double val) Get the value of the named double field from the persistent field.
abstract long	get(String name, long val) Get the value of the named long field from the persistent field.
abstract Object	get(String name, Object val) Get the value of the named Object field from the persistent field.
abstract ObjectStreamClass	getObjectStreamClass() Get the ObjectStreamClass that describes the fields in the stream.

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.

Public Constructors

public GetField ()

Public Methods

public abstract boolean defaulted (String name)

Return true if the named field is defaulted and has no value in this stream.

Parameters

name	the name of the field

Returns

• true, if and only if the named field is defaulted

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if name does not correspond to a serializable field

public abstract boolean get (String name, boolean val)

Get the value of the named boolean field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named boolean field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract byte get (String name, byte val)

Get the value of the named byte field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named byte field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract short get (String name, short val)

Get the value of the named short field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named short field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract char get (String name, char val)

Get the value of the named char field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named char field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract int get (String name, int val)

Get the value of the named int field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named int field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract float get (String name, float val)

Get the value of the named float field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named float field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract double get (String name, double val)

Get the value of the named double field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named double field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract long get (String name, long val)

Get the value of the named long field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named long field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract Object get (String name, Object val)

Get the value of the named Object field from the persistent field.

Parameters

name	the name of the field
val	the default value to use if name does not have a value

Returns

• the value of the named Object field

Throws

IOException	if there are I/O errors while reading from the underlying InputStream
IllegalArgumentException	if type of name is not serializable or if the field type is incorrect

public abstract ObjectStreamClass getObjectStreamClass ()

Get the ObjectStreamClass that describes the fields in the stream.

Returns

• the descriptor class that describes the serializable fields