javolution.context

Class PersistentContext

java.lang.Object

javolution.context.Context

javolution.context.PersistentContext

All Implemented Interfaces:

java.io.Serializable, XMLSerializable

public class PersistentContext
extends Context

This class represents a context persistent accross multiple program executions. It is typically used to hold persistent references.

How this context is loaded/saved is application specific. Although, the simplest way is to use Javolution XML serialization facility. For example:

      import javolution.xml.XMLObjectReader;
      import javolution.xml.XMLObjectWriter;
      public void main(String[]) {
           // Loads persistent context (typically at start-up).
           XMLObjectReader reader = XMLObjectReader.newInstance(new FileInputStream("C:/persistent.xml"));
           PersistentContext.setCurrentPersistentContext(reader.read());
           reader.close();
           ...
           ...
           // Saves persistent context for future execution.
           XMLObjectWriter writer = XMLObjectWriter.newInstance(new FileOutputStream("C:/persistent.xml"));
           writer.write(PersistentContext.getCurrentPersistentContext());
           writer.close();
      }

Version:

4.2, December 31, 2006

Author:

Jean-Marie Dautelle

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PersistentContext.Reference<T> This class represents a reference over an object which can be kept persistent accross multiple program executions.

Field Summary

Fields inherited from class javolution.context.Context

ROOT

Constructor Summary

Constructors

Constructor and Description
PersistentContext() Default constructor.

Method Summary

Modifier and Type	Method and Description
protected void	enterAction() Throws UnsupportedOperationException persistent context are global to all threads (singleton).
protected void	exitAction() Throws UnsupportedOperationException persistent context are global to all threads (singleton).
static PersistentContext	getCurrentPersistentContext() Returns the persistent context instance (singleton).
java.util.Map<java.lang.String,java.lang.Object>	getIdToValue() Returns the ID to value mapping for this persistent context.
static void	setCurrentPersistentContext(PersistentContext ctx) Sets the persistent instance.

Methods inherited from class javolution.context.Context

enter, enter, exit, exit, getCurrentContext, getOuter, getOwner, setConcurrentContext, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

PersistentContext

public PersistentContext()

Default constructor.

Method Detail

setCurrentPersistentContext

public static void setCurrentPersistentContext(PersistentContext ctx)

Sets the persistent instance.

Parameters:

ctx - the persistent instance.

getCurrentPersistentContext

public static PersistentContext getCurrentPersistentContext()

Returns the persistent context instance (singleton).

Returns:

the persistent context instance.

getIdToValue

public java.util.Map<java.lang.String,java.lang.Object> getIdToValue()

Returns the ID to value mapping for this persistent context.

Returns:

the persistent value indexed by identifiers.

enterAction

protected void enterAction()

Throws UnsupportedOperationException persistent context are global to all threads (singleton).

Specified by:

enterAction in class Context

exitAction

protected void exitAction()

Throws UnsupportedOperationException persistent context are global to all threads (singleton).

Specified by:

exitAction in class Context