This class holds values of named
fields and allows them to be written to
an ObjectOutputStream during the process of object
serialization. It gives the programmer
precise control over the serialization process and is typically used
when the set of fields defined by a class does not match the set of
fields (and the serialization stream format) defined by the original
implementation of the class. In other words,
ObjectOutputStream.PutField allows the
implementation of a class to change without breaking serialization
compatibility.
In order to use the PutField class, you typically
define a private static serialPersistentFields
field that refers to an array of ObjectStreamField
objects. This array defines the set of fields written to the
ObjectOutputStream and therefore defines the
serialization format. If you do not declare a
serialPersistentFields field, the set of fields is
all fields of the class, excluding static and
TRansient fields.
In
addition to the serialPersistentFields field, your
class must also define a private writeObject( )
method that is responsible for the custom serialization of your
class. In this method, call the putFields( )
method of ObjectOutputStream to obtain an
ObjectOutputStream.PutField object. Once you have
this object, use its various put( ) methods to
specify the names and values of the field to be written out. The set
of named fields should match those specified by
serialPersistentFields. You may specify the fields
in any order; the PutField class is responsible
for writing them out in the correct order. Once you have specified
the values of all fields, call the write( ) method
of your PutField object in order to write the
field values out to the serialization stream.
To reverse this custom serialization process, see
ObjectInputStream.GetField.
public abstract static class ObjectOutputStream.PutField {
// Public Constructors
public PutField( );
// Public Instance Methods
public abstract void put(String name, long val);
public abstract void put(String name, int val);
public abstract void put(String name, float val);
public abstract void put(String name, Object val);
public abstract void put(String name, double val);
public abstract void put(String name, byte val);
public abstract void put(String name, boolean val);
public abstract void put(String name, short val);
public abstract void put(String name, char val);
// Deprecated Public Methods
# public abstract void write(ObjectOutput out) throws IOException;
}
