org.apache.derby.impl.io.vfmem
Class DataStore

java.lang.Object
  extended by org.apache.derby.impl.io.vfmem.DataStore

public final class DataStore
extends java.lang.Object

A virtual data store, keeping track of all the virtual files existing and offering a set of high-level operations on virtual files.

A newly created data store doesn't contain a single existing directory.


Field Summary
private  java.lang.String databaseName
          The name of the database this store serves, expected to be the absolute path of the service root (i.e.
private  boolean deleteMe
          Tells if this store is scheduled for deletion.
private static java.lang.String[] EMPTY_STR_ARR
          Constant for the empty String array.
private  java.util.Map files
          The files exsiting in the store.
private  java.lang.Object LOCK
          Lock object for the file map.
private static char SEP
          The path separator used.
private  java.lang.Object TMP_COUNTER_LOCK
          Lock object for the temporary file counter.
private  long tmpFileCounter
          Counter used to generate unique temporary file names.
 
Constructor Summary
DataStore(java.lang.String databaseName)
          Creates a new data store.
 
Method Summary
private  boolean _deleteAll(java.lang.String prefixPath)
          Deletes every child of the root path specified.
 boolean createAllParents(java.lang.String path)
          Creates all the parents of the specified path.
 DataStoreEntry createEntry(java.lang.String iPath, boolean isDir)
          Creates a new entry in the data store.
 boolean deleteAll(java.lang.String iPath)
          Deletes the specified entry and all its children.
 boolean deleteEntry(java.lang.String iPath)
          Deletes the specified entry.
 java.lang.String getDatabaseName()
          Returns the database name, which is expected to equal the path of the service root.
 DataStoreEntry getEntry(java.lang.String iPath)
          Returns the entry with the specified path.
private  java.lang.String[] getParentList(java.lang.String path)
          Returns the list of parents for the specified path.
 long getTempFileCounter()
          Returns an identifier for a temporary file.
 java.lang.String[] listChildren(java.lang.String iPath)
          Lists the childen of the specified path.
 boolean move(StorageFile currentFile, StorageFile newFile)
          Moves / renames a file.
 void purge()
          Purges the database and releases all files associated with it.
 boolean scheduledForDeletion()
          Tells if this data store is scheduled for deletion.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SEP

private static final char SEP
The path separator used.


EMPTY_STR_ARR

private static final java.lang.String[] EMPTY_STR_ARR
Constant for the empty String array.


LOCK

private final java.lang.Object LOCK
Lock object for the file map.


TMP_COUNTER_LOCK

private final java.lang.Object TMP_COUNTER_LOCK
Lock object for the temporary file counter.


files

private final java.util.Map files
The files exsiting in the store.

The initial size is set to the number of initial files of a Derby database, pluss a few more.


databaseName

private final java.lang.String databaseName
The name of the database this store serves, expected to be the absolute path of the service root (i.e. /tmp/myDB if the database myDB is created in /tmp).


tmpFileCounter

private long tmpFileCounter
Counter used to generate unique temporary file names.


deleteMe

private boolean deleteMe
Tells if this store is scheduled for deletion.

Constructor Detail

DataStore

public DataStore(java.lang.String databaseName)
Creates a new data store.

Parameters:
databaseName - the name of the assoicated database, expected to be the absolute path of the service root.
Method Detail

getDatabaseName

public java.lang.String getDatabaseName()
Returns the database name, which is expected to equal the path of the service root.

Returns:
The database name.

scheduledForDeletion

public boolean scheduledForDeletion()
Tells if this data store is scheduled for deletion.

Returns:
true if the store is awaiting deletion, false otherwise.

createEntry

public DataStoreEntry createEntry(java.lang.String iPath,
                                  boolean isDir)
Creates a new entry in the data store.

This method returns null if the path already exists, if one of the parent directories doesn't exist, or if one of the parents is a file instead of a directory.

Parameters:
iPath - the path of the entry
isDir - tells if the new entry shall be directory or a file
Returns:
A DataStoreEntry-instance if the entry was successfully created, null otherwise

createAllParents

public boolean createAllParents(java.lang.String path)
Creates all the parents of the specified path.

Returns:
true if all parents either already existed as directories or were created, false otherwise

deleteEntry

public boolean deleteEntry(java.lang.String iPath)
Deletes the specified entry.

If the specified entry is a directory, it is only deleted if it is empty. Read-only entries are deleted.

Parameters:
iPath - path of the entry to delete
Returns:
true if the entry was deleted, false otherwise.

getEntry

public DataStoreEntry getEntry(java.lang.String iPath)
Returns the entry with the specified path.

Parameters:
iPath - path of the entry to fetch
Returns:
null if the entry doesn't exist, the DataStoreEntry-object otherwise.

deleteAll

public boolean deleteAll(java.lang.String iPath)
Deletes the specified entry and all its children.

Parameters:
iPath - the root entry
Returns:
true if the entry and all its children were deleted, false if the root doesn't exist.

listChildren

public java.lang.String[] listChildren(java.lang.String iPath)
Lists the childen of the specified path.

Parameters:
iPath - the directory to list the children of
Returns:
An array with the relative paths of the children.

move

public boolean move(StorageFile currentFile,
                    StorageFile newFile)
Moves / renames a file.

Parameters:
currentFile - the current file
newFile - the new file
Returns:
true if the file was moved, false if the new file already existed or the existing file doesn't exist.

purge

public void purge()
Purges the database and releases all files associated with it.


_deleteAll

private boolean _deleteAll(java.lang.String prefixPath)
Deletes every child of the root path specified.

Note that the root itself must be removed outside of this method.

Parameters:
prefixPath - the normalized root path to start deleting from
Returns:
true if all children of the root path were deleted, false otherwise.

getTempFileCounter

public long getTempFileCounter()
Returns an identifier for a temporary file.

Returns:
An integer uniquely identifying a temporary file.

getParentList

private java.lang.String[] getParentList(java.lang.String path)
Returns the list of parents for the specified path.

The lowest level parent is listed first in the list, so all absolute paths will have the root listed as the last element.

Parameters:
path - the normalized path to create a parent list for
Returns:
A list of parents.

Built on Thu 2011-03-10 11:54:14+0000, from revision ???

Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.