org.apache.derby.impl.io

Class DirStorageFactory

java.lang.Object

org.apache.derby.impl.io.BaseStorageFactory

org.apache.derby.impl.io.DirStorageFactory

All Implemented Interfaces:

StorageFactory, WritableStorageFactory

Direct Known Subclasses:

DirStorageFactory4

public class DirStorageFactory
extends BaseStorageFactory
implements WritableStorageFactory

This class provides a disk based implementation of the StorageFactory interface. It is used by the database engine to access persistent data and transaction logs under the directory (default) subsubprotocol.

Field Summary

Fields inherited from class org.apache.derby.impl.io.BaseStorageFactory

canonicalName, dataDirectory, home, separatedDataDirectory, tempDir, tempDirPath, uniqueName

Fields inherited from interface org.apache.derby.io.StorageFactory

VERSION_NUMBER

Constructor Summary

Constructors

Constructor and Description
DirStorageFactory()

Method Summary

Methods

Modifier and Type	Method and Description
(package private) void	doInit()
boolean	isReadOnlyDatabase() Determine whether the database is read only.
(package private) StorageFile	newPersistentFile(StorageFile directoryName, java.lang.String fileName) Construct a persistent StorageFile from a directory and path name.
(package private) StorageFile	newPersistentFile(java.lang.String path) Construct a persistent StorageFile from a path name.
(package private) StorageFile	newPersistentFile(java.lang.String directoryName, java.lang.String fileName) Construct a persistent StorageFile from a directory and path name.
StorageFile	newStorageFile(StorageFile directoryName, java.lang.String fileName) Construct a StorageFile from a directory and file name.
StorageFile	newStorageFile(java.lang.String path) Construct a StorageFile from a path name.
StorageFile	newStorageFile(java.lang.String directoryName, java.lang.String fileName) Construct a StorageFile from a directory and file name.
boolean	supportsRandomAccess() Determine whether the storage supports random access.
boolean	supportsWriteSync() This method tests whether the "rws" and "rwd" modes are implemented.
void	sync(java.io.OutputStream stream, boolean metaData) Force the data of an output stream out to the underlying storage.

Methods inherited from class org.apache.derby.impl.io.BaseStorageFactory

createTempDir, createTemporaryFile, getCanonicalName, getSeparator, getStorageFactoryVersion, getTempDir, init, isFast, setCanonicalName, shutdown

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.io.StorageFactory

createTemporaryFile, getCanonicalName, getSeparator, getStorageFactoryVersion, getTempDir, init, isFast, setCanonicalName, shutdown

Constructor Detail

DirStorageFactory

public DirStorageFactory()

Method Detail

newStorageFile

public final StorageFile newStorageFile(java.lang.String path)

Construct a StorageFile from a path name.

Specified by:

newStorageFile in interface StorageFactory

Overrides:

newStorageFile in class BaseStorageFactory

Parameters:

path - The path name of the file

Returns:

A corresponding StorageFile object

newStorageFile

public final StorageFile newStorageFile(java.lang.String directoryName,
                         java.lang.String fileName)

Construct a StorageFile from a directory and file name.

Specified by:

newStorageFile in interface StorageFactory

Overrides:

newStorageFile in class BaseStorageFactory

Parameters:

directoryName - The directory part of the path name.

fileName - The name of the file within the directory.

Returns:

A corresponding StorageFile object

newStorageFile

public final StorageFile newStorageFile(StorageFile directoryName,
                         java.lang.String fileName)

Construct a StorageFile from a directory and file name.

Specified by:

newStorageFile in interface StorageFactory

Overrides:

newStorageFile in class BaseStorageFactory

Parameters:

directoryName - The directory part of the path name.

fileName - The name of the file within the directory.

Returns:

A corresponding StorageFile object

newPersistentFile

StorageFile newPersistentFile(java.lang.String path)

Construct a persistent StorageFile from a path name.

Specified by:

newPersistentFile in class BaseStorageFactory

Parameters:

path - The path name of the file. Guaranteed not to be in the temporary file directory. If null then the database directory should be returned.

Returns:

A corresponding StorageFile object

newPersistentFile

StorageFile newPersistentFile(java.lang.String directoryName,
                            java.lang.String fileName)

Construct a persistent StorageFile from a directory and path name.

Specified by:

newPersistentFile in class BaseStorageFactory

Parameters:

directoryName - The path name of the directory. Guaranteed not to be in the temporary file directory. Guaranteed not to be null

fileName - The name of the file within the directory. Guaranteed not to be null.

Returns:

A corresponding StorageFile object

newPersistentFile

StorageFile newPersistentFile(StorageFile directoryName,
                            java.lang.String fileName)

Construct a persistent StorageFile from a directory and path name.

Specified by:

newPersistentFile in class BaseStorageFactory

Parameters:

directoryName - The path name of the directory. Guaranteed not to be to be null. Guaranteed to be created by a call to one of the newPersistentFile methods.

fileName - The name of the file within the directory. Guaranteed not to be null.

Returns:

A corresponding StorageFile object

sync

public void sync(java.io.OutputStream stream,
        boolean metaData)
          throws java.io.IOException,
                 java.io.SyncFailedException

Force the data of an output stream out to the underlying storage. That is, ensure that it has been made persistent. If the database is to be transient, that is, if the database does not survive a restart, then the sync method implementation need not do anything.

Specified by:

sync in interface WritableStorageFactory

Parameters:

stream - The stream to be synchronized.

metaData - If true then this method must force both changes to the file's contents and metadata to be written to storage; if false, it need only force file content changes to be written. The implementation is allowed to ignore this parameter and always force out metadata changes.

Throws:

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

java.io.SyncFailedException - Thrown when the buffers cannot be flushed, or because the system cannot guarantee that all the buffers have been synchronized with physical media.

supportsWriteSync

public boolean supportsWriteSync()

This method tests whether the "rws" and "rwd" modes are implemented. If the "rws" and "rwd" modes are supported then the database engine will conclude that the write methods of "rws"/"rwd" mode StorageRandomAccessFiles are slow but the sync method is fast and optimize accordingly.

Specified by:

supportsWriteSync in interface WritableStorageFactory

Returns:

true if an StIRandomAccess file opened with "rws" or "rwd" modes immediately writes data to the underlying storage, false if not.

isReadOnlyDatabase

public boolean isReadOnlyDatabase()

Description copied from interface: StorageFactory

Determine whether the database is read only. The database engine supports read-only databases, even in file systems that are writable.

Specified by:

isReadOnlyDatabase in interface StorageFactory

Overrides:

isReadOnlyDatabase in class BaseStorageFactory

Returns:

true if the storage is read only, false if it is writable.

supportsRandomAccess

public boolean supportsRandomAccess()

Determine whether the storage supports random access. If random access is not supported then it will only be accessed using InputStreams and OutputStreams (if the database is writable).

Specified by:

supportsRandomAccess in interface StorageFactory

Overrides:

supportsRandomAccess in class BaseStorageFactory

Returns:

true if the storage supports random access, false if it is writable.

doInit

void doInit()
      throws java.io.IOException

Specified by:

doInit in class BaseStorageFactory

Throws:

java.io.IOException