java.util.prefs
Class TransientPreferences

java.lang.Object
  |
  +--java.util.prefs.Preferences
        |
        +--java.util.prefs.AbstractPreferences
              |
              +--java.util.prefs.TransientPreferences

public class TransientPreferences

extends AbstractPreferences

This specialization of AbstractPreferences provides a means of holding transient contextual settings to pass from one program entity to another, such as between isolates. There is no connection between transient preferences and the backing store used by regular preferences; however, export/import to and from XML is supported. Export of transient preferences to XML is via the inherited exportNode method, but import is via an additional constructor. Here are some code fragments demonstrating TransientPreferences usage:

 // Pass a few context values to a new isolate
 TransientPreferences ctx = new TransientPreferences();
 ctx.put("workPath", "inventory.update");
 ctx.put("workClass", "restock");
 Isolate newIsolate = Isolate( ... ctx, ...);

 // Merge above preferences with existing one and save it to XML
 ctx.merge(existingCtx);
 ctx.export(new FileOutputStream("batchupdate_prefs.xml");
 
 // Retrieve preferences from a stream, customize and use
 TransientPreferences ictx = new TransientPreferences(new
                 FileInputStream("some_prefs.xml"));
 ictx.remove("historyFlag");
 Isolate myIsolate = Isolate( ... ictx, ...);




Since:
  
1.5










Field Summary

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



Constructor Summary
TransientPreferences()



          Constructs an empty context.
TransientPreferences(InputStream is)



          Constructs a new context from preferences XML form
TransientPreferences(TransientPreferences base)



          Constructs a new context with the same initial contents as given base.
 



Method Summary




 void
merge(TransientPreferences source)



          Merges in a tree of preferences, replacing existing nodes and/or values 
 with the same name.


 
Methods inherited from class java.util.prefs.AbstractPreferences
absolutePath, addNodeChangeListener, addPreferenceChangeListener, childrenNames, clear, exportNode, exportSubtree, flush, get, getBoolean, getByteArray, getDouble, getFloat, getInt, getLong, 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, systemNodeForPackage, systemRoot, userNodeForPackage, userRoot
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 








Constructor Detail



TransientPreferences
public TransientPreferences()

Constructs an empty context.





TransientPreferences
public TransientPreferences(TransientPreferences base)

Constructs a new context with the same initial contents as given base.

Parameters:
base - the existing TransientPreferences object to copy



TransientPreferences
public TransientPreferences(InputStream is)
                     throws IOException,
                            InvalidPreferencesFormatException

Constructs a new context from preferences XML form

Parameters:
is - the input stream from which to read the XML document.
Throws:
IOException - if reading from the specified output stream 
 results in an IOException
InvalidPreferencesFormatException - if data on input stream does 
 not constitute a valid XML document with the mandated document type




Method Detail



merge
public void merge(TransientPreferences source)

Merges in a tree of preferences, replacing existing nodes and/or values 
 with the same name.


Parameters:
source - the preferences object to merge