PreferencesRootWrapper (Jetspeed-2 Portal Commons 2.1.4 API)

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org.apache.jetspeed.util
Class PreferencesRootWrapper

java.lang.Object
  java.util.prefs.Preferences
      org.apache.jetspeed.util.PreferencesRootWrapper

All Implemented Interfaces:: java.util.Observer

public class PreferencesRootWrapper
extends java.util.prefs.Preferences
implements java.util.Observer
extends java.util.prefs.Preferences
implements java.util.Observer

PreferencesRootWrapper is a lightweight wrapper around the Jetspeed persistent PreferencesImpl to allow restarting the Jetspeed Portal.

As the (Sun) Java Preferences implementation only creates a PreferencesFactory instance *once* per JVM (as static final), reloading the Jetspeed Portal (using a new classloader) requires a wrapper solution to prevent ClassCastExceptions and/or out-of-sync kept proxies and caches.

As a newly created Jetspeed Portal classloader can no longer cast a previous Preferences root to its own PreferencesImpl, a "trick" is used by also implementing the Observer interface (which is provided by the Java system classloader). The Observer interface is used because it is very lightweight and allows passing an Object instance through its update method. That update method is used to "inject" the newly created Preferences root instance.

Version:: $Id: PreferencesRootWrapper.java 740489 2009-02-03 22:25:06Z taylor $
Author:: Ate Douma

Field Summary

Fields inherited from class java.util.prefs.Preferences
`MAX_KEY_LENGTH, MAX_NAME_LENGTH, MAX_VALUE_LENGTH`

Constructor Summary
`PreferencesRootWrapper()`

Method Summary
`java.lang.String`	`absolutePath()`
`void`	`addNodeChangeListener(java.util.prefs.NodeChangeListener ncl)`
`void`	`addPreferenceChangeListener(java.util.prefs.PreferenceChangeListener pcl)`
`java.lang.String[]`	`childrenNames()`
`void`	`clear()`
`boolean`	`equals(java.lang.Object obj)`
`void`	`exportNode(java.io.OutputStream os)`
`void`	`exportSubtree(java.io.OutputStream os)`
`void`	`flush()`
`java.lang.String`	`get(java.lang.String key, java.lang.String def)`
`boolean`	`getBoolean(java.lang.String key, boolean def)`
`byte[]`	`getByteArray(java.lang.String key, byte[] def)`
`double`	`getDouble(java.lang.String key, double def)`
`float`	`getFloat(java.lang.String key, float def)`
`int`	`getInt(java.lang.String key, int def)`
`long`	`getLong(java.lang.String key, long def)`
`int`	`hashCode()`
`boolean`	`isUserNode()`
`java.lang.String[]`	`keys()`
`java.lang.String`	`name()`
`java.util.prefs.Preferences`	`node(java.lang.String pathName)`
`boolean`	`nodeExists(java.lang.String pathName)`
`java.util.prefs.Preferences`	`parent()`
`void`	`put(java.lang.String key, java.lang.String value)`
`void`	`putBoolean(java.lang.String key, boolean value)`
`void`	`putByteArray(java.lang.String key, byte[] value)`
`void`	`putDouble(java.lang.String key, double value)`
`void`	`putFloat(java.lang.String key, float value)`
`void`	`putInt(java.lang.String key, int value)`
`void`	`putLong(java.lang.String key, long value)`
`void`	`remove(java.lang.String key)`
`void`	`removeNode()`
`void`	`removeNodeChangeListener(java.util.prefs.NodeChangeListener ncl)`
`void`	`removePreferenceChangeListener(java.util.prefs.PreferenceChangeListener pcl)`
`void`	`sync()`
`java.lang.String`	`toString()`
`void`	`update(java.util.Observable o, java.lang.Object arg)`

Methods inherited from class java.util.prefs.Preferences
`importPreferences, systemNodeForPackage, systemRoot, userNodeForPackage, userRoot`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Constructor Detail