Class VaadinPreferences

java.lang.Object

java.util.prefs.Preferences

java.util.prefs.AbstractPreferences

vaadinx.util.prefs.VaadinPreferences

public final class VaadinPreferences
extends AbstractPreferences

A java.util.prefs.Preferences node backed by the browser's localStorage — the web-faithful analog of Swing's machine-local preferences store (Windows registry / ~/.java/.userPrefs/ / macOS plist). Selected JVM-wide by VaadinPreferencesFactory through the standard PreferencesFactory SPI, so migrated code keeps calling Preferences.userNodeForPackage(...) unchanged. See D_preferences.

Extending AbstractPreferences means the tree walk, keys()/childrenNames()/node(path)/removeNode(), and the PreferenceChangeListener/NodeChangeListener fan-out all come from the JDK. This class implements only the nine backing *Spi methods, delegating storage to the per-UI PrefsCache.

The class is public only so tests and diagnostics can name the type; every constructor is non-public, so user code cannot instantiate a node directly (it obtains nodes via Preferences.userRoot() et al.).

Change listeners fire for local mutations (this UI) via AbstractPreferences; a mutation in another browser tab does not fire here — the documented multi-tab gap (D_preferences).

Field Summary

Fields inherited from class AbstractPreferences

lock, newNode

Fields inherited from class Preferences

MAX_KEY_LENGTH, MAX_NAME_LENGTH, MAX_VALUE_LENGTH

Method Summary

Modifier and Type	Method	Description
protected String[]	childrenNamesSpi()
protected AbstractPreferences	childSpi(String name)
protected void	flushSpi()
protected String	getSpi(String key)
boolean	isUserNode()	Always true.
protected String[]	keysSpi()
protected void	putSpi(String key, String value)
protected void	removeNodeSpi()
protected void	removeSpi(String key)
protected void	syncSpi()

Methods inherited from class AbstractPreferences

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

Methods inherited from class Preferences

importPreferences, systemNodeForPackage, systemRoot, userNodeForPackage, userRoot

Methods inherited from class Object

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

Method Details

getSpi

protected String getSpi(String key)

Specified by:

getSpi in class AbstractPreferences

putSpi

protected void putSpi(String key,
 String value)

Specified by:

putSpi in class AbstractPreferences

removeSpi

protected void removeSpi(String key)

Specified by:

removeSpi in class AbstractPreferences

keysSpi

protected String[] keysSpi()
                    throws BackingStoreException

Specified by:

keysSpi in class AbstractPreferences

Throws:

BackingStoreException

childrenNamesSpi

protected String[] childrenNamesSpi()
                             throws BackingStoreException

Specified by:

childrenNamesSpi in class AbstractPreferences

Throws:

BackingStoreException

childSpi

protected AbstractPreferences childSpi(String name)

Specified by:

childSpi in class AbstractPreferences

removeNodeSpi

protected void removeNodeSpi()
                      throws BackingStoreException

Specified by:

removeNodeSpi in class AbstractPreferences

Throws:

BackingStoreException

syncSpi

protected void syncSpi()
                throws BackingStoreException

Specified by:

syncSpi in class AbstractPreferences

Throws:

BackingStoreException

flushSpi

protected void flushSpi()
                 throws BackingStoreException

Specified by:

flushSpi in class AbstractPreferences

Throws:

BackingStoreException

isUserNode

public boolean isUserNode()

Always true. Overridden so we don't inherit AbstractPreferences.isUserNode()'s default, which compares against Preferences.userRoot() — that would re-enter our factory and require a current UI just to answer a boolean.

Overrides:

isUserNode in class AbstractPreferences