jdbm

Interface RecordManager

All Known Subinterfaces:

ActionRecordManager

All Known Implementing Classes:

BaseRecordManager, CacheRecordManager, SnapshotRecordManager

public interface RecordManager

An interface to manages records, which are uninterpreted blobs of data.

The set of record operations is simple: fetch, insert, update and delete. Each record is identified using a "rowid" and contains a byte[] data block. Rowids are returned on inserts and you can store them someplace safe to be able to get back to them. Data blocks can be as long as you wish, and may have lengths different from the original when updating.

Author:

Alex Boisvert, Cees de Groot

Field Summary

Fields

Modifier and Type	Field and Description
static int	NAME_DIRECTORY_ROOT Reserved slot for name directory.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the record manager.
void	commit() Commit (make persistent) all changes since beginning of transaction.
void	delete(long recid) Deletes a record.
Object	fetch(long recid) Fetches a record using standard java object serialization.
Object	fetch(long recid, Serializer serializer) Fetches a record using a custom serializer.
long	getNamedObject(String name) Obtain the record id of a named object.
long	getRoot(int id) Returns the indicated root rowid.
int	getRootCount() Returns the number of slots available for "root" rowids.
long	insert(Object obj) Inserts a new record using standard java object serialization.
long	insert(Object obj, Serializer serializer) Inserts a new record using a custom serializer.
void	rollback() Rollback (cancel) all changes since beginning of transaction.
void	setNamedObject(String name, long recid) Set the record id of a named object.
void	setRoot(int id, long rowid) Sets the indicated root rowid.
void	update(long recid, Object obj) Updates a record using standard java object serialization.
void	update(long recid, Object obj, Serializer serializer) Updates a record using a custom serializer.

Field Detail

NAME_DIRECTORY_ROOT

static final int NAME_DIRECTORY_ROOT

Reserved slot for name directory.

See Also:

Constant Field Values

Method Detail

insert

long insert(Object obj)
     throws IOException

Inserts a new record using standard java object serialization.

Parameters:

obj - the object for the new record.

Returns:

the rowid for the new record.

Throws:

IOException - when one of the underlying I/O operations fails.

insert

long insert(Object obj,
            Serializer serializer)
     throws IOException

Inserts a new record using a custom serializer.

Parameters:

obj - the object for the new record.

serializer - a custom serializer

Returns:

the rowid for the new record.

Throws:

IOException - when one of the underlying I/O operations fails.

delete

void delete(long recid)
     throws IOException

Deletes a record.

Parameters:

recid - the rowid for the record that should be deleted.

Throws:

IOException - when one of the underlying I/O operations fails.

update

void update(long recid,
            Object obj)
     throws IOException

Updates a record using standard java object serialization.

Parameters:

recid - the recid for the record that is to be updated.

obj - the new object for the record.

Throws:

IOException - when one of the underlying I/O operations fails.

update

void update(long recid,
            Object obj,
            Serializer serializer)
     throws IOException

Updates a record using a custom serializer.

Parameters:

recid - the recid for the record that is to be updated.

obj - the new object for the record.

serializer - a custom serializer

Throws:

IOException - when one of the underlying I/O operations fails.

fetch

Object fetch(long recid)
      throws IOException

Fetches a record using standard java object serialization.

Parameters:

recid - the recid for the record that must be fetched.

Returns:

the object contained in the record.

Throws:

IOException - when one of the underlying I/O operations fails.

fetch

Object fetch(long recid,
             Serializer serializer)
      throws IOException

Fetches a record using a custom serializer.

Parameters:

recid - the recid for the record that must be fetched.

serializer - a custom serializer

Returns:

the object contained in the record.

Throws:

IOException - when one of the underlying I/O operations fails.

close

void close()
    throws IOException

Closes the record manager.

Throws:

IOException - when one of the underlying I/O operations fails.

getRootCount

int getRootCount()

Returns the number of slots available for "root" rowids. These slots can be used to store special rowids, like rowids that point to other rowids. Root rowids are useful for bootstrapping access to a set of data.

getRoot

long getRoot(int id)
      throws IOException

Returns the indicated root rowid.

Throws:

IOException

See Also:

getRootCount()

setRoot

void setRoot(int id,
             long rowid)
      throws IOException

Sets the indicated root rowid.

Throws:

IOException

See Also:

getRootCount()

commit

void commit()
     throws IOException

Commit (make persistent) all changes since beginning of transaction.

Throws:

IOException

rollback

void rollback()
       throws IOException

Rollback (cancel) all changes since beginning of transaction.

Throws:

IOException

getNamedObject

long getNamedObject(String name)
             throws IOException

Obtain the record id of a named object. Returns 0 if named object doesn't exist.

Throws:

IOException

setNamedObject

void setNamedObject(String name,
                    long recid)
             throws IOException

Set the record id of a named object.

Throws:

IOException