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java.lang.Object
   |
   +----utah.npm.core.Lockable
           |
           +----utah.npm.core.ThreadWait

Summary

final class  ThreadWait
     extends utah.npm.core.Lockable
{
          // Fields 18
     static final int IPC_CL_ACK;
     static final int IPC_CL_ANY;
     static final int IPC_CL_CONNECT;
     static final int IPC_CL_DISCONN;
     static final int IPC_CL_OVER;
     static final int IPC_CL_RECV;
     static final int IPC_CL_SEND;
     static final int IPC_SR_ACK;
     static final int IPC_SR_ANY;
     static final int IPC_SR_CONNECT;
     static final int IPC_SR_DISCONN;
     static final int IPC_SR_OVER;
     static final int IPC_SR_RECV;
     static final int IPC_SR_SEND;
     static final int WAIT_NONE;
     private int resumeRC_;
     private boolean validWakeup_;
     private int waitState_;

          // Constructors 1
     public ThreadWait();

          // Methods 7
     boolean captureIn(int);
     String debugInfo();
     void destroy();
     boolean isWaitingIn(int);
     void kick(int);
     void setWaitState(int);
     int waitIn(int, Lockable, int);
}

Per-thread "wait" information. This class encapsulates thread sleeping, and lets other threads "capture" sleeping threads.

Version:

NPMJava 0.5.0 April, 1998

Author:

Patrick Tullmann tullmann@cs.utah.edu

Fields

· waitState_

Summary  |  Top

   private int waitState_

The state this thread is "waiting in". This identifies what sort of event this thread is blocked on. The envents are defined below.

   private int resumeRC_

The standard integer status code this thread is to return when it is awoken.

   private boolean validWakeup_

A private boolean indicating if a thread wakeup was spurious or not.

   static final int WAIT_NONE

   static final int IPC_SR_DISCONN

   static final int IPC_SR_CONNECT

   static final int IPC_SR_SEND

   static final int IPC_SR_RECV

   static final int IPC_SR_ACK

   static final int IPC_SR_OVER

   static final int IPC_SR_ANY

   static final int IPC_CL_DISCONN

   static final int IPC_CL_CONNECT

   static final int IPC_CL_SEND

   static final int IPC_CL_RECV

   static final int IPC_CL_ACK

   static final int IPC_CL_OVER

   static final int IPC_CL_ANY

Constructors

· ThreadWait

Summary  |  Top

   public ThreadWait() 

Default constructor

   boolean captureIn(int expectedState) 

Capture this thread if its waiting in expectedState.

XXX This will have to go native when inheritance scheduling is implemented.

Parameter	Description
expectedState	must be on of the states defined above.

Returns:

true if the thread is captured, false otherwise.

   boolean isWaitingIn(int reqState) 

Check to seee if this thread is blocked in the given wait state (or some specialization of that wait state.)

Parameter	Description
reqState	the state to compare waitState_ against.

Returns:

true if thread is that state, false otherwise.

   int waitIn(int waitState, 
              Lockable lock, 
              int resumeRC) 

Cause the current thread to wait in state waitState. When the thread resumes it will return its resumeRc, which will defaults to the provided resumeRC. (But, other threads can access and manipulate the resumeRC.) The provided Lockable object, if not null, will be unlocked before the thread is put to sleep.

This object had best be locked on entry, and is unlocked when the function returns.

This function will not return unless the calling thread is explicitly woken up by some other thread.

Parameter	Description
waitState	The wait state to record this thread as blocked in.
lock	a lockable object to s_unlock() before sleeping.
resumeRC	The initial value to use as a return code when the thread is awoken.

Returns:

The thread's resumeRc at the time of waking.

See Also: Lockable

   void setWaitState(int waitState) 

Set the current thread's recorded wait state. This should only be called on captured threads that already have some wait state.

Parameter	Description
waitState	the wait state to record.

   void kick(int resumeRC) 

Resume this thread (which must be captured.)

Parameter	Description
resumeRC	return code for the target thread to resume with

   void destroy() 

Destroy this per-thread wait information. This is only called by Thread.destroy()

See Also: Thread.destroy

   String debugInfo() 

Return a string describing this thread's current wait state. TODO: remove dependencies on Integer class and StringBuffer class.

Returns:

a string describing this thread's current wait state.

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