Package ucar.util.prefs

Class PreferencesExt

java.lang.Object
java.util.prefs.Preferences
java.util.prefs.AbstractPreferences
ucar.util.prefs.PreferencesExt
All Implemented Interfaces:
PersistenceManager
public class PreferencesExt extends AbstractPreferences implements PersistenceManager
An extension of java.util.prefs.Preferences (jdk 1.4) that provides a platform-independent implementation using XML files as backing store.

To save Java beans, use putBean() and putBeanCollection(). This uses reflection to get/set properties that have simple single-valued accessor methods of primitive and String type.

For arbitrary objects, use putBeanObject(), which uses the XMLEncode/XMLDecode API (jdk 1.4). To obtain a PreferencesExt object, instantiate an XMLStore object and call XMLStore.getPreferences().

See Also:

  • Constructor Details

    • PreferencesExt

      public PreferencesExt(PreferencesExt parent, String name)
      Constructor. Usually you get a PreferencesExt object from XMLStore.getPrefs(), rather than constructing one directly. For the root node, parent = null and name = "".

  • Method Details

    • setUserRoot

      public static void setUserRoot(PreferencesExt prefs)
      Set the user root you get when you call Preferences.userRoot().

    • setSystemRoot

      public static void setSystemRoot(PreferencesExt prefs)
      Set the system root you get when you call Preferences.systemRoot().

    • isUserNode

      public boolean isUserNode()
      return true unless this is the systemRoot node
      Overrides:
      isUserNode in class AbstractPreferences

    • getBean

      public Object getBean(String key, Object def)
      Get the object that has the specified key. This returns the object itself, not a copy, so if you change the bean and call store.save(), any changes to the object will be saved, even without calling putBean(). If you want to change the object without saving the changes, you must make a copy of the object yourself.
      Parameters:
      key - get the object with this key.
      def - the default value to be returned in the event that this preference node has no value associated with key.
      Returns:
      the value associated with key, or def if no value is associated with key.
      Throws:
      IllegalStateException - if this node (or an ancestor) has been removed with the AbstractPreferences.removeNode() method.
      NullPointerException - if key is null. (A null default is permitted.)

    • putBean

      public void putBean(String key, Object newValue)
      Stores an object using simple bean properties. If the exact key and value are already in the storedDefaults (using equals() to test for equality), then it is not stored.
      Parameters:
      key - key with which the specified value is to be associated.
      newValue - store this bean.
      Throws:
      NullPointerException - if key or value is null.
      IllegalStateException - if this node (or an ancestor) has been removed with the AbstractPreferences.removeNode() method.

    • putBeanCollection

      public void putBeanCollection(String key, Collection newValue)
      Stores a Collection of beans. The beans are stored using simple bean properties. The collection of beans must all be of the same class.
      Parameters:
      key - key with which the specified collection is to be associated.
      newValue - store this collection of beans.
      Throws:
      NullPointerException - if key or value is null.
      IllegalStateException - if this node (or an ancestor) has been removed with the AbstractPreferences.removeNode() method.

    • putBeanObject

      public void putBeanObject(String key, Object newValue)
      Stores an object using XMLEncoder/XMLDecoder. Use this for arbitrary objects. If the exact key and value are already in the storedDefaults (using equals() to test for equality), then it is not stored.
      Parameters:
      key - key with which the specified value is to be associated.
      newValue - store this bean object.
      Throws:
      NullPointerException - if key or value is null.
      IllegalStateException - if this node (or an ancestor) has been removed with the AbstractPreferences.removeNode() method.

    • getList

      public List getList(String key, List def)
      Get an arrayList. This returns a copy of the stored list.
      Specified by:
      getList in interface PersistenceManager
      Parameters:
      key - key whose associated value is to be returned.
      def - the value to be returned in the event that this preference node has no value associated with key.
      Returns:
      the value associated with key, or def if no value is associated with key.

    • putList

      public void putList(String key, List newValue)
      Stores the value with this key, if the exact key and value are not already in the storedDefaults (using equals() to test for equality). "Two lists are defined to be equal if they contain the same elements in the same order."
      Specified by:
      putList in interface PersistenceManager
      Parameters:
      key - key with which the specified value is to be associated.
      newValue - value to be associated with the specified key.

    • childrenNamesSpi

      protected String[] childrenNamesSpi()
      Implements AbstractPreferences childrenNamesSpi() method. Find all children nodes of this node (or of identically named nodes in storedDefaults)
      Specified by:
      childrenNamesSpi in class AbstractPreferences

    • childrenNamesSpi

      protected Collection childrenNamesSpi(String nodePath)

    • keysSpi

      protected String[] keysSpi() throws BackingStoreException
      Specified by:
      keysSpi in class AbstractPreferences
      Throws:
      BackingStoreException

    • keysSpi

      protected Collection keysSpi(String nodePath)

    • childSpi

      protected AbstractPreferences childSpi(String name)
      Specified by:
      childSpi in class AbstractPreferences

    • flushSpi

      protected void flushSpi() throws BackingStoreException
      Empty, never used implementation of AbstractPreferences.flushSpi().
      Specified by:
      flushSpi in class AbstractPreferences
      Throws:
      BackingStoreException

    • getSpi

      protected String getSpi(String keyName)
      Specified by:
      getSpi in class AbstractPreferences

    • putSpi

      protected void putSpi(String key, String newValue)
      Specified by:
      putSpi in class AbstractPreferences

    • removeNodeSpi

      protected void removeNodeSpi() throws BackingStoreException
      Specified by:
      removeNodeSpi in class AbstractPreferences
      Throws:
      BackingStoreException

    • removeSpi

      protected void removeSpi(String key)
      removes key/value if exists, no effect on storedDefaults Remove the association (if any) for the specified key at this preference node. It is guaranteed that key is non-null. Also, it is guaranteed that this node has not been removed. (The implementor needn't check for either of these things.) This method is invoked with the lock on this node held.
      Specified by:
      removeSpi in class AbstractPreferences

    • syncSpi

      protected void syncSpi() throws BackingStoreException
      Specified by:
      syncSpi in class AbstractPreferences
      Throws:
      BackingStoreException

    • putObject

      public void putObject(String keyName, Object value)
      Specified by:
      putObject in interface PersistenceManager

    • getObject

      public Object getObject(String key)
      Specified by:
      getObject in interface PersistenceManager