org.apache.derby.impl.io
Class DirFile4

java.lang.Object
  java.io.File
      org.apache.derby.impl.io.DirFile
          org.apache.derby.impl.io.DirFile4

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<java.io.File>, StorageFile

 class DirFile4
extends DirFile

This class implements the StorageFile interface using features of Java 1.4 not available in earlier versions of Java.

Field Summary

private java.nio.channels.FileLock	dbLock
private java.nio.channels.FileChannel	lockFileChannel
private java.io.RandomAccessFile	lockFileOpen

Fields inherited from class java.io.File

pathSeparator, pathSeparatorChar, separator, separatorChar

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

EXCLUSIVE_FILE_LOCK, EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE, NO_FILE_LOCK_SUPPORT

Constructor Summary

DirFile4(DirFile directoryName, java.lang.String fileName)
Construct a DirFile from a directory name and a file name.

DirFile4(java.lang.String path)
Construct a DirFile from a path name.

DirFile4(java.lang.String directoryName, java.lang.String fileName)
Construct a DirFile from a directory name and a file name.

Method Summary

int	getExclusiveFileLock() Get an exclusive lock.
java.io.OutputStream	getOutputStream(boolean append) Creates an output stream from a file name.
StorageFile	getParentDir() Get the name of the parent directory if this name includes a parent.
StorageRandomAccessFile	getRandomAccessFile(java.lang.String mode) Get a random access (read/write) file.
void	releaseExclusiveFileLock() Release the resource associated with an earlier acquired exclusive lock

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

deleteAll, getInputStream, getOutputStream, getURL, limitAccessToOwner, renameTo

Methods inherited from class java.io.File

canExecute, canRead, canWrite, compareTo, createNewFile, createTempFile, createTempFile, delete, deleteOnExit, equals, exists, getAbsoluteFile, getAbsolutePath, getCanonicalFile, getCanonicalPath, getFreeSpace, getName, getParent, getParentFile, getPath, getTotalSpace, getUsableSpace, hashCode, isAbsolute, isDirectory, isFile, isHidden, lastModified, length, list, list, listFiles, listFiles, listFiles, listRoots, mkdir, mkdirs, renameTo, setExecutable, setExecutable, setLastModified, setReadable, setReadable, setReadOnly, setWritable, setWritable, toString, toURI, toURL

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

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

canWrite, createNewFile, delete, exists, getCanonicalPath, getName, getPath, isDirectory, length, list, mkdir, mkdirs, setReadOnly

Field Detail

lockFileOpen

private java.io.RandomAccessFile lockFileOpen

lockFileChannel

private java.nio.channels.FileChannel lockFileChannel

dbLock

private java.nio.channels.FileLock dbLock

Constructor Detail

DirFile4

DirFile4(java.lang.String path)

Construct a DirFile from a path name.

Parameters:

path - The path name.

DirFile4

DirFile4(java.lang.String directoryName,
         java.lang.String fileName)

Construct a DirFile from a directory name and a file name.

Parameters:

directoryName - The directory part of the path name.

fileName - The name of the file within the directory.

DirFile4

DirFile4(DirFile directoryName,
         java.lang.String fileName)

Construct a DirFile from a directory name and a file name.

Parameters:

directoryName - The directory part of the path name.

fileName - The name of the file within the directory.

Method Detail

getParentDir

public StorageFile getParentDir()

Get the name of the parent directory if this name includes a parent.

Specified by:

getParentDir in interface StorageFile

Overrides:

getParentDir in class DirFile

Returns:

An StorageFile denoting the parent directory of this StorageFile, if it has a parent, null if it does not have a parent.

getOutputStream

public java.io.OutputStream getOutputStream(boolean append)
                                     throws java.io.FileNotFoundException

Creates an output stream from a file name.

Specified by:

getOutputStream in interface StorageFile

Overrides:

getOutputStream in class DirFile

Parameters:

append - If true then data will be appended to the end of the file, if it already exists. If false and a normal file already exists with this name the file will first be truncated to zero length.

Returns:

an output stream suitable for writing to the file.

Throws:

java.io.FileNotFoundException - if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.

getExclusiveFileLock

public int getExclusiveFileLock()
                         throws StandardException

Description copied from class: DirFile

Get an exclusive lock. This is used to ensure that two or more JVMs do not open the same database at the same time.

Specified by:

getExclusiveFileLock in interface StorageFile

Overrides:

getExclusiveFileLock in class DirFile

Returns:

EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE if the lock cannot be acquired because it is already held.
EXCLUSIVE_FILE_LOCK if the lock was successfully acquired.
NO_FILE_LOCK_SUPPORT if the system does not support exclusive locks.

Throws:

StandardException

releaseExclusiveFileLock

public void releaseExclusiveFileLock()

Description copied from class: DirFile

Release the resource associated with an earlier acquired exclusive lock

Specified by:

releaseExclusiveFileLock in interface StorageFile

Overrides:

releaseExclusiveFileLock in class DirFile

See Also:

DirFile.getExclusiveFileLock()

getRandomAccessFile

public StorageRandomAccessFile getRandomAccessFile(java.lang.String mode)
                                            throws java.io.FileNotFoundException

Get a random access (read/write) file.

Specified by:

getRandomAccessFile in interface StorageFile

Overrides:

getRandomAccessFile in class DirFile

Parameters:

mode - "r", "rw", "rws", or "rwd". The "rws" and "rwd" modes specify that the data is to be written to persistent store, consistent with the java.io.RandomAccessFile class ("synchronized" with the persistent storage, in the file system meaning of the word "synchronized"). However the implementation is not required to implement the "rws" or "rwd" modes. The implementation may treat "rws" and "rwd" as "rw". It is up to the user of this interface to call the StorageRandomAccessFile.sync method. If the "rws" or "rwd" modes are supported and the RandomAccessFile was opened in "rws" or "rwd" mode then the implementation of StorageRandomAccessFile.sync need not do anything.

Returns:

an object that can be used for random access to the file.

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd".

java.io.FileNotFoundException - if the file exists but is a directory rather than a regular file, or cannot be opened or created for any other reason .

See Also:

java.io.RandomAccessFile