Direct Known Subclasses:

ConcurrentContext, FormatContext, LocalContext, LogContext, SecurityContext

@Realtime
@Parallelizable(comment="Sequential configuration, parallel use")
public abstract class AbstractContext
extends Object 

 AnyContext ctx = AnyContext.enter(); // Enters a context scope. 
 try { 
 ctx.configure(...); // Local configuration (optional).
 ... // Current thread executes using the configured context.
 } finally {
 ctx.exit(); 
 }

Version:

6.0, July 21, 2013

Author:

Jean-Marie Dautelle

• Constructor Summary

  Constructors

  Modifier	Constructor and Description
  protected	AbstractContext () Default constructor.

• Method Summary

  Methods

  Modifier and Type	Method and Description
  static AbstractContext	current () Returns the current context for the current thread or null if this thread has no context (default).
  protected static <T extends AbstractContext> T	current (Class<T> type) Returns the current context of specified type or null if none.
  static <T extends AbstractContext> T	enter (Class<T> custom) Enters the scope of a custom context.
  protected AbstractContext	enterInner () Enters the scope of an inner context which becomes the current context; the previous current context becomes the outer of this context.
  void	exit () Exits the scope of this context; the outer of this context becomes the current context.
  protected AbstractContext	getOuter () Returns the outer context of this context or null if this context has no outer context.
  static void	inherit (AbstractContext ctx) Inherits the specified context which becomes the context of the current thread.
  protected abstract AbstractContext	inner () Returns a new inner instance of this context inheriting the properties of this context.

  • Methods inherited from class java.lang.Object

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

• Constructor Detail

  • AbstractContext

    protected AbstractContext()

    Default constructor.

• Method Detail

  • current

    public static AbstractContext current()

    Returns the current context for the current thread or null if this thread has no context (default).

  • current

    protected static <T extends AbstractContext> T current(Class<T> type)

    Returns the current context of specified type or null if none.

  • enter

    public static <T extends AbstractContext> T enter(Class<T> custom)

    Enters the scope of a custom context. This method raises a SecurityException if the permission to enter contexts of the specified class is not granted. For example, the following disallow entering any custom context.

     SecurityContext ctx = SecurityContext.enter(); 
     try {
     ctx.revoke(new SecurityContext.Permission(AbstractContext.class, "enter"));
     ... // Cannot enter any custom context.
     } finally {
     ctx.exit(); // Back to previous security settings. 
     }

    Parameters:

    custom - the custom context to enter.

    Throws:

    IllegalArgumentException - if the specified class default constructor cannot be instantiated.

    SecurityException - if SecurityContext.Permission(custom, "enter") is not granted.

    See Also:

    SecurityContext.Permission

  • inherit

    public static void inherit(AbstractContext ctx)

    Inherits the specified context which becomes the context of the current thread. This method is particularly useful when creating new threads to make them inherits from the context stack of the parent thread.

     //Spawns a new thread inheriting the context of the current thread.
     MyThread myThread = new MyThread();
     myThread.inherited = AbstractContext.current(); 
     myThread.start(); 
     ...
     class MyThread extends Thread {
     AbstractContext inherited;
     public void run() {
     AbstractContext.inherit(inherited); // Sets current context. 
     ...
     }
     }

  • enterInner

    protected AbstractContext enterInner()

    Enters the scope of an inner context which becomes the current context; the previous current context becomes the outer of this context.

    Returns:

    the inner context entered.

  • exit

    public void exit()

    Exits the scope of this context; the outer of this context becomes the current context.

    Throws:

    IllegalStateException - if this context is not the current context.

  • getOuter

    protected AbstractContext getOuter()

    Returns the outer context of this context or null if this context has no outer context.

  • inner

    protected abstract AbstractContext inner()

    Returns a new inner instance of this context inheriting the properties of this context. The new instance can be configured independently from its parent.