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  1. JDK
  2. JDK-4886212

Need general-purpose way to dispatch object invocations on Java GUI thread

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      Description

      Java AWT/Swing is effectively single-threaded. Requests that execute
      against Java GUI components often need to execute on the Java GUI
      event loop thread.

      We have a large number of object interfaces that must execute on the
      Java GUI thread but are dispatched by the Java POA on a POA pool thread.
      (it is not possible for us to dispatch each method call individually to
      the GUI thread within each object implementation)

      We can use a Tie class to dispatch each invocation to the Java
      GUI thread, but then we get an exception because com.sun.corba.se.internal.POA.POACurrent.peekThrowInternal() uses
      a ThreadLocal stack of InvocationInfo objects, and the GUI thread
      does not have the stack; only the original POA thread has it.

      We can fix this by creating (within a Tie class) the appropriate
      InvocationInfo object on a ThreadLocal associated with the GUI thread,
      populating it within info from the POA thread's stack,
      and then popping it before returning to the regular POA dispatch
      method.

      We have developed a simple fix that exposes (makes public)
      three methods on POACurrent: addThreadInfo(), removeThreadInfo(),
      peekThrowNoContext(). We do not believe this is likely to be
      an acceptable solution so we would like to work with the
      java-idl team to identify a better one.

      The attachment AccessibleImpl.java contains our Tie-proxy class
      AccessiblePOATieProxy; this shows how we dispatch the
      invocation to the GUI thread (in real_invoke, we use
      SwingUtility.invokeAndWait() to execute a command
      AWTInvocation. The calls to the (formerly) private Java IDL
      methods are in this method and in AWTInvocation.run().

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            Assignee:
            pcashman Pat Cashman
            Reporter:
            duke J. Duke (Inactive)
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