Package com.sleepycat.bind.serial

Interface ClassCatalog

All Known Implementing Classes:

StoredClassCatalog

public interface ClassCatalog

A catalog of class description information for use during object serialization.

A catalog is used to store class descriptions separately from serialized objects, to avoid redundantly stored information with each object. When serialized objects are stored in a database, a StoredClassCatalog should be used.

This information is used for serialization of class descriptors or java.io.ObjectStreamClass objects, each of which represents a unique class format. For each unique format, a unique class ID is assigned by the catalog. The class ID can then be used in the serialization stream in place of the full class information. When used with SerialInput and SerialOutput or any of the serial bindings, the use of the catalog is transparent to the application.

See Also:

Class Evolution

Method Summary

Modifier and Type	Method	Description
void	close()	Close a catalog database and release any cached resources.
java.io.ObjectStreamClass	getClassFormat(byte[] classID)	Return the ObjectStreamClass for the given class ID.
byte[]	getClassID(java.io.ObjectStreamClass classDesc)	Return the class ID for the current version of the given class description.
java.lang.ClassLoader	getClassLoader()	Returns the ClassLoader to be used by bindings that use this catalog, or null if a default class loader should be used.

Method Detail

close

void close()
    throws DatabaseException

Close a catalog database and release any cached resources.

Throws:

DatabaseException - if an error occurs closing the catalog database.

getClassID

byte[] getClassID(java.io.ObjectStreamClass classDesc)
           throws DatabaseException,
                  java.lang.ClassNotFoundException

Return the class ID for the current version of the given class description. This is used for storing in serialization streams in place of a full class descriptor, since it is much more compact. To get back the ObjectStreamClass for a class ID, call getClassFormat(byte[]). This function causes a new class ID to be assigned if the class description has changed.

Parameters:

classDesc - The class description for which to return the class ID.

Returns:

The class ID for the current version of the class.

Throws:

DatabaseException - if an error occurs accessing the catalog database.

java.lang.ClassNotFoundException - if the class does not exist.

getClassFormat

java.io.ObjectStreamClass getClassFormat(byte[] classID)
                                  throws DatabaseException,
                                         java.lang.ClassNotFoundException

Return the ObjectStreamClass for the given class ID. This may or may not be the current class format, depending on whether the class has changed since the class ID was generated.

Parameters:

classID - The class ID for which to return the class format.

Returns:

The class format for the given class ID, which may or may not represent the current version of the class.

Throws:

DatabaseException - if an error occurs accessing the catalog database.

java.lang.ClassNotFoundException - if the class does not exist.

getClassLoader

java.lang.ClassLoader getClassLoader()

Returns the ClassLoader to be used by bindings that use this catalog, or null if a default class loader should be used. The ClassLoader is used by SerialBinding to load classes whose description is stored in the catalog.

In BDB JE, the implementation of this method in StoredClassCatalog returns the ClassLoader property of the catalog database Environment. This ensures that the Environment's ClassLoader property is used for loading all user-supplied classes.

Returns:

the ClassLoader or null.