sos.db
Class FileDatabase

java.lang.Object
  sos.db.AbstractDatabase
      sos.db.AbstractSerializationDatabase
          sos.db.FileDatabase

All Implemented Interfaces:

java.io.Serializable, Database

public class FileDatabase
extends AbstractSerializationDatabase
implements Database

A persistent database that stores objects in a random-access file.

Logging

Instances of this database log database activity. See AbstractSerializationDatabase for more information.

External Serialization

Proxy objects can be serialized to a stream outside of the database. See AbstractSerializationDatabase for more information.

Since:

1.0

See Also:

AbstractSerializationDatabase, TransactionPolicy, InMemoryDatabase

Field Summary

Fields inherited from interface sos.db.Database

logger

Constructor Summary

FileDatabase(java.lang.String databaseName, java.lang.String fileName)
Creates a FileDatabase with the specified database name.

FileDatabase(java.lang.String databaseName, java.lang.String fileName, TransactionPolicy policy)
Creates a FileDatabase with the specified database name and transaction policy.

Method Summary

protected void	doClose() Performs the action of close.
protected boolean	doCreate(java.lang.Object root) Performs the action of create.
protected boolean	doDelete() Performs the action of delete.
protected boolean	doExists() Performs the action of exists.
protected byte[]	doFetchObject(long id) Returns the serialized object associated with id.
protected boolean	doFlush(LongMap<byte[]> newObjects, LongMap<byte[]> modifiedObjects, Progress progress) Adds new objects, re-saves modified objects, and removes old objects from this database in a single, atomic step.
protected long	doNextKey(long fromKey) Returns the next key greater than or equal to fromKey that corresponds to an object in this database.
protected void	doOpen(boolean readOnly) Performs the action of open.
protected void	doRemoveObject(long oldKey) Removes the specified object from this database.

Methods inherited from class sos.db.AbstractSerializationDatabase

createDefaultTransactionPolicy, doAbortTransaction, doAddObject, doCommitTransaction, doContainsObject, doGetRoot, doStartTransaction, doTransactionDepth, enableReplaceObject, getName, getTransactionPolicy, logDatabaseClosed, logDatabaseCreated, logDatabaseDeleted, logDatabaseOpened, logObjectAdded, logObjectRemoved, logObjectResaved, logTransactionAborted, logTransactionCommitted, logTransactionStarted, readResolve, replaceObject, resolveObject, setAutoCreateTransactions

Methods inherited from class sos.db.AbstractDatabase

abortTransaction, addObject, close, commitTransaction, containsObject, create, delete, exists, getRoot, isOpen, open, startTransaction, transactionDepth

Methods inherited from class java.lang.Object

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

Methods inherited from interface sos.db.Database

abortTransaction, addObject, close, commitTransaction, containsObject, create, delete, exists, getName, getRoot, getTransactionPolicy, isOpen, open, startTransaction, transactionDepth

Constructor Detail

FileDatabase

public FileDatabase(java.lang.String databaseName,
                    java.lang.String fileName)

Creates a FileDatabase with the specified database name.

Parameters:

databaseName - name of the database

fileName - name of the file to use the database

Throws:

java.lang.NullPointerException - if fileName is null

See Also:

FileDatabase(String,String,TransactionPolicy)

FileDatabase

public FileDatabase(java.lang.String databaseName,
                    java.lang.String fileName,
                    TransactionPolicy policy)

Creates a FileDatabase with the specified database name and transaction policy.

Parameters:

databaseName - name of the database

fileName - name of the file to use the database

policy - policy to use to control transactions (may be null)

Throws:

java.lang.NullPointerException - if fileName is null

Method Detail

doClose

protected void doClose()
                throws java.io.IOException

Description copied from class: AbstractDatabase

Performs the action of close. This method is called inside close if this database is in an acceptable state. It has the same semantics as close.

Overrides:

doClose in class AbstractSerializationDatabase

Throws:

java.io.IOException - if an I/O error occurs

See Also:

AbstractDatabase.close()

doCreate

protected boolean doCreate(java.lang.Object root)
                    throws java.io.IOException

Description copied from class: AbstractDatabase

Performs the action of create. This method is called inside create if this database is in an acceptable state. It has the same semantics as create.

Overrides:

doCreate in class AbstractSerializationDatabase

Parameters:

root - the root of this database

Returns:

true if this database does not exist and was successfully created; false if this database already exists

Throws:

java.io.IOException - if an I/O error occurs

See Also:

AbstractDatabase.create(java.lang.Object)

doDelete

protected boolean doDelete()
                    throws java.io.IOException

Description copied from class: AbstractDatabase

Performs the action of delete. This method is called inside delete if this database is in an acceptable state. It has the same semantics as delete.

Overrides:

doDelete in class AbstractSerializationDatabase

Returns:

true if this database is successfully deleted

Throws:

java.io.IOException - if an I/O error occurs

See Also:

AbstractDatabase.delete()

doExists

protected boolean doExists()

Description copied from class: AbstractDatabase

Performs the action of exists. This method is called inside exists if this database is in an acceptable state. It has the same semantics as exists.

Specified by:

doExists in class AbstractDatabase

Returns:

true if this database exists

See Also:

AbstractDatabase.exists()

doFetchObject

protected byte[] doFetchObject(long id)
                        throws java.io.IOException

Description copied from class: AbstractSerializationDatabase

Returns the serialized object associated with id.

This method is called while holding this database's monitor.

Specified by:

doFetchObject in class AbstractSerializationDatabase

Parameters:

id - id of object to fetch

Returns:

the serialized object associated with id

Throws:

java.io.IOException - if an I/O error occurs

doFlush

protected boolean doFlush(LongMap<byte[]> newObjects,
                          LongMap<byte[]> modifiedObjects,
                          Progress progress)
                   throws java.io.IOException

Description copied from class: AbstractSerializationDatabase

Adds new objects, re-saves modified objects, and removes old objects from this database in a single, atomic step. If any of these steps should fail, the database should roll back to its state prior to the call.

This method is called when a top-level transaction commits. It is called while holding this database's monitor.

Specified by:

doFlush in class AbstractSerializationDatabase

Parameters:

newObjects - a mapping of new ids (as Longs) to new database objects (as byte[]s)

modifiedObjects - a mapping of ids (as Longs) to modified database objects (as byte[]s)

progress - an object to be updated and checked as the flush is occurring (may be null)

Returns:

false if it is interrupted because the progress is canceled; true otherwise

Throws:

java.io.IOException - if an I/O error occurs

doNextKey

protected long doNextKey(long fromKey)
                  throws java.io.IOException

Description copied from class: AbstractSerializationDatabase

Returns the next key greater than or equal to fromKey that corresponds to an object in this database. This method is called while holding this database's monitor.

Specified by:

doNextKey in class AbstractSerializationDatabase

Parameters:

fromKey - key from which to start the search

Returns:

the key of the next database object or -1, if no more database objects

Throws:

java.io.IOException - if an I/O error occurs

doRemoveObject

protected void doRemoveObject(long oldKey)
                       throws java.io.IOException

Description copied from class: AbstractSerializationDatabase

Removes the specified object from this database.

This method is called when a garbage collection finds the object unreachable. It is called while holding this database's monitor.

Specified by:

doRemoveObject in class AbstractSerializationDatabase

Parameters:

oldKey - keys of the object to remove from this database

Throws:

java.io.IOException - if an I/O error occurs

doOpen

protected void doOpen(boolean readOnly)
               throws java.io.IOException

Description copied from class: AbstractDatabase

Performs the action of open. This method is called inside open if this database is in an acceptable state. It has the same semantics as open.

Overrides:

doOpen in class AbstractSerializationDatabase

Parameters:

readOnly - true if database updates are not allowed

Throws:

java.io.IOException - if an I/O error occurs

See Also:

AbstractDatabase.open