org.apache.jdo.impl.fostore

Class FOStoreBtreeStorage

java.lang.Object

org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeStorage

org.apache.jdo.impl.fostore.FOStoreBtreeStorage

All Implemented Interfaces:

org.netbeans.mdr.persistence.Storage

public class FOStoreBtreeStorage
extends org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeStorage

FOStore specific BtreeStorage subclass. This class manages MOFIDs for a FOStore datastore. A MOFID consists of two parts: a storageId of type String and a serial number of type long. When storing on disk the storageId is converted into a number and stored as 16-bit value. Only 48 bits of the serial number get represented on disk. FOStore uses the serial number to encode the uid part of an OID and the storageId for the class id of an OID. The btree class MOFIDInfo converts a MOFID into a byte array of 8 bytes that is stored on disk. The two high order bytes represent the storageId. Class MOFIDInfo calls method storageIdToNumber to convert a String storageId into a number. The remaining 6 bytes represent the serial number.

Since:

1.1

Version:

1.1

Author:

Michael Bouschen

Nested Class Summary

Nested classes/interfaces inherited from interface org.netbeans.mdr.persistence.Storage

org.netbeans.mdr.persistence.Storage.EntryType

Constructor Summary

Constructors

Constructor and Description
FOStoreBtreeStorage(java.lang.String name, boolean isNew) Creates a new FOStoreBtreeStorage instance.

Method Summary

Methods

Modifier and Type	Method and Description
org.netbeans.mdr.persistence.MOFID	createMOFID(int clid, long uid) Returns Creates a MOFID based on the class id and uid taken from a FOStore OID.
java.lang.String	numberToStorageId(int number) Creates a storage id from an int.
int	storageIdToNumber(java.lang.String storageId) Converts a storageId to an int.

Methods inherited from class org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeStorage

close, commitChanges, create, createMultivaluedIndex, createMultivaluedOrderedIndex, createSinglevaluedIndex, delete, dropIndex, exists, getIndex, getMOFIDData, getMofidGenerator, getMofidMap, getMultivaluedIndex, getMultivaluedOrderedIndex, getName, getPrimaryIndex, getSerialNumber, getSinglevaluedIndex, getStorageId, objectStateChanged, objectStateWillChange, open, readMOFID, readMOFIDData, resolveObject, rollBackChanges, shutDown, supportsMultipleStorableIndexes, writeMOFID, writeMOFIDData

Methods inherited from class java.lang.Object

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

Constructor Detail

FOStoreBtreeStorage

public FOStoreBtreeStorage(java.lang.String name,
                   boolean isNew)
                    throws org.netbeans.mdr.persistence.StorageException

Creates a new FOStoreBtreeStorage instance. The constructor creates or opens a storage based on the specified argument isNew.

Parameters:

name - the name of the storage.

isNew - true if the database is being created

Throws:

org.netbeans.mdr.persistence.StorageException

Method Detail

createMOFID

public org.netbeans.mdr.persistence.MOFID createMOFID(int clid,
                                             long uid)

Returns Creates a MOFID based on the class id and uid taken from a FOStore OID. The storageId of the returned MOFID represents the class id and the serial number represents the uid.

Parameters:

clid - the class id

uid - the unique id

Returns:

MOFID representing class id and uid taken from FOStore OID.

storageIdToNumber

public int storageIdToNumber(java.lang.String storageId)
                      throws org.netbeans.mdr.persistence.StorageException

Converts a storageId to an int. If the specified storageId starts with CLID_PREFIX, then the storageId represents a class id. In this case use the class id as the numeric reresentation.

Overrides:

storageIdToNumber in class org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeStorage

Parameters:

storageId - the storageId as String

Returns:

the numeric representation of the storageId

Throws:

org.netbeans.mdr.persistence.StorageException

numberToStorageId

public java.lang.String numberToStorageId(int number)
                                   throws org.netbeans.mdr.persistence.StorageException

Creates a storage id from an int. It returns the FOStore specific String representation for a storageId representing a class id.

Overrides:

numberToStorageId in class org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeStorage

Parameters:

number - the numberic representation of the storageId

Returns:

the storageId as String

Throws:

org.netbeans.mdr.persistence.StorageException