moss.kernel
Class MWaitQueue

java.lang.Object
  moss.kernel.MWaitQueue

public class MWaitQueue
extends java.lang.Object

this class implements a wait-queue. Wait-queues are used for process-context operations, such as keeping track of blocked processes inside a device-driver. This class doesn't do any scheduling itself. It doesn't do any locking itself, either. Thus, lock outside if necessary.

Constructor Summary

MWaitQueue()
constructor -- creates an empty wait-queue

Method Summary

boolean	add_to_queue(MProcess p) adds a process to the wait-queue
boolean	del_from_queue(MProcess p) removes a specific process from the wait-queue
MProcess	get_from_queue() removes the first process from the wait-queue
boolean	is_empty() tests whether a queue is empty

Methods inherited from class java.lang.Object

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

Constructor Detail

MWaitQueue

public MWaitQueue()

constructor -- creates an empty wait-queue

Method Detail

add_to_queue

public boolean add_to_queue(MProcess p)

adds a process to the wait-queue

Parameters:

p - process to add

Returns:

true if the process was added, false if not (already there)

get_from_queue

public MProcess get_from_queue()

removes the first process from the wait-queue

Returns:

process removed, or null if empty

del_from_queue

public boolean del_from_queue(MProcess p)

removes a specific process from the wait-queue

Parameters:

p - process to remove

Returns:

true if the process was removed, false otherwise (not here)

is_empty

public boolean is_empty()

tests whether a queue is empty

Returns:

true if empty, false if waiting processes