java.util.prefs

Class FilePreferencesImpl

java.lang.Object

java.util.prefs.Preferences

java.util.prefs.AbstractPreferences

java.util.prefs.FilePreferencesImpl

public class FilePreferencesImpl
extends AbstractPreferences

The default implementation of AbstractPreferences for the Linux platform, using the file system as its back end. TODO some sync mechanism with backend, Performance - check file edit date

Since:

1.4

Field Summary

Fields inherited from class java.util.prefs.AbstractPreferences

lock, newNode

Fields inherited from class java.util.prefs.Preferences

MAX_KEY_LENGTH, MAX_NAME_LENGTH, MAX_VALUE_LENGTH

Constructor Summary

Constructors

Constructor and Description
FilePreferencesImpl(String path, boolean isUserNode) Construct root FilePreferencesImpl instance rooted at the given path.

Method Summary

Modifier and Type	Method and Description
protected String[]	childrenNamesSpi() Returns the names of all of the child nodes of this node or an empty array if this node has no children.
protected AbstractPreferences	childSpi(String name) Returns the child preference node with the given name, creating it if it does not exist.
protected void	flushSpi() Flushes changes of this node to the backing store.
protected String	getSpi(String key) Gets the preference value mapped to the given key.
protected String[]	keysSpi() Returns an array of all preference keys of this node or an empty array if no preferences have been found.
protected void	putSpi(String name, String value) Puts the given key-value pair into this node.
protected void	removeNodeSpi() Removes this node from the preference hierarchy tree.
protected void	removeSpi(String key) Removes the preference with the specified key.
protected void	syncSpi() Synchronizes this node with the backing store.

Methods inherited from class java.util.prefs.AbstractPreferences

absolutePath, addNodeChangeListener, addPreferenceChangeListener, cachedChildren, childrenNames, clear, exportNode, exportSubtree, flush, get, getBoolean, getByteArray, getChild, getDouble, getFloat, getInt, getLong, isRemoved, isUserNode, keys, name, node, nodeExists, parent, put, putBoolean, putByteArray, putDouble, putFloat, putInt, putLong, remove, removeNode, removeNodeChangeListener, removePreferenceChangeListener, sync, toString

Methods inherited from class java.util.prefs.Preferences

importPreferences, setPreferencesFactory, systemNodeForPackage, systemRoot, userNodeForPackage, userRoot

Methods inherited from class java.lang.Object

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

Constructor Detail

FilePreferencesImpl

public FilePreferencesImpl(String path,
                           boolean isUserNode)

Construct root FilePreferencesImpl instance rooted at the given path.

Method Detail

childrenNamesSpi

protected String[] childrenNamesSpi()
                             throws BackingStoreException

Description copied from class: AbstractPreferences

Returns the names of all of the child nodes of this node or an empty array if this node has no children. The names of cached children are not required to be returned.

Specified by:

childrenNamesSpi in class AbstractPreferences

Returns:

the names of this node's children.

Throws:

BackingStoreException - if the backing store is unavailable or causes an operation failure.

childSpi

protected AbstractPreferences childSpi(String name)

Description copied from class: AbstractPreferences

Returns the child preference node with the given name, creating it if it does not exist. The caller of this method should ensure that the given name is valid and that this node has not been removed or cached. If the named node has just been removed, the implementation of this method must create a new one instead of reactivating the removed one.

The new creation is not required to be persisted immediately until the flush method will be invoked.

Specified by:

childSpi in class AbstractPreferences

Parameters:

name - the name of the child preference to be returned.

Returns:

the child preference node.

flushSpi

protected void flushSpi()
                 throws BackingStoreException

Description copied from class: AbstractPreferences

Flushes changes of this node to the backing store. This method should only flush this node and should not include the descendant nodes. Any implementation that wants to provide functionality to flush all nodes at once should override the method flush().

Specified by:

flushSpi in class AbstractPreferences

Throws:

BackingStoreException - if the backing store is unavailable or causes an operation failure.

getSpi

protected String getSpi(String key)

Description copied from class: AbstractPreferences

Gets the preference value mapped to the given key. The caller of this method should ensure that the given key is valid and that this node has not been removed. This method should not throw any exceptions but if it does, the caller will ignore the exception, regarding it as a null return value.

Specified by:

getSpi in class AbstractPreferences

Parameters:

key - the given key to be searched for.

Returns:

the preference value mapped to the given key.

keysSpi

protected String[] keysSpi()
                    throws BackingStoreException

Description copied from class: AbstractPreferences

Returns an array of all preference keys of this node or an empty array if no preferences have been found. The caller of this method should ensure that this node has not been removed.

Specified by:

keysSpi in class AbstractPreferences

Returns:

the array of all preference keys.

Throws:

BackingStoreException - if the backing store is unavailable or causes an operation failure.

putSpi

protected void putSpi(String name,
                      String value)

Description copied from class: AbstractPreferences

Puts the given key-value pair into this node. Caller of this method should ensure that both of the given values are valid and that this node has not been removed.

Specified by:

putSpi in class AbstractPreferences

Parameters:

name - the given preference key.

value - the given preference value.

removeNodeSpi

protected void removeNodeSpi()
                      throws BackingStoreException

Description copied from class: AbstractPreferences

Removes this node from the preference hierarchy tree. The caller of this method should ensure that this node has no child nodes, which means the method Preferences.removeNode() should invoke this method multiple-times in bottom-up pattern. The removal is not required to be persisted until after it is flushed.

Specified by:

removeNodeSpi in class AbstractPreferences

Throws:

BackingStoreException - if the backing store is unavailable or causes an operation failure.

removeSpi

protected void removeSpi(String key)

Description copied from class: AbstractPreferences

Removes the preference with the specified key. The caller of this method should ensure that the given key is valid and that this node has not been removed.

Specified by:

removeSpi in class AbstractPreferences

Parameters:

key - the key of the preference that is to be removed.

syncSpi

protected void syncSpi()
                throws BackingStoreException

Description copied from class: AbstractPreferences

Synchronizes this node with the backing store. This method should only synchronize this node and should not include the descendant nodes. An implementation that wants to provide functionality to synchronize all nodes at once should override the method sync().

Specified by:

syncSpi in class AbstractPreferences

Throws:

BackingStoreException - if the backing store is unavailable or causes an operation failure.