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root/jsr166/jsr166/src/jsr166y/Phaser.java

Comparing jsr166/src/jsr166y/Phaser.java (file contents):
Revision 1.22 by jsr166, Sun Jul 26 17:33:37 2009 UTC vs.
Revision 1.40 by dl, Mon Aug 24 12:49:39 2009 UTC

#	Line 12 | Line 12 | import java.util.concurrent.atomic.Atomi
12		import java.util.concurrent.locks.LockSupport;
13
14		/**
15	<	* A reusable synchronization barrier, similar in functionality to a
15	>	* A reusable synchronization barrier, similar in functionality to
16		* {@link java.util.concurrent.CyclicBarrier CyclicBarrier} and
17		* {@link java.util.concurrent.CountDownLatch CountDownLatch}
18		* but supporting more flexible usage.
19		*
20	<	* <ul>
21	<	*
22	<	* <li> The number of parties synchronizing on a phaser may vary over
23	<	* time.  A task may register to be a party at any time, and may
24	<	* deregister upon arriving at the barrier.  As is the case with most
25	<	* basic synchronization constructs, registration and deregistration
26	<	* affect only internal counts; they do not establish any further
27	<	* internal bookkeeping, so tasks cannot query whether they are
28	<	* registered. (However, you can introduce such bookkeeping by
29	<	* subclassing this class.)
30	<	*
31	<	* <li> Each generation has an associated phase value, starting at
32	<	* zero, and advancing when all parties reach the barrier (wrapping
33	<	* around to zero after reaching {@code Integer.MAX_VALUE}).
34	<	*
35	<	* <li> Like a CyclicBarrier, a Phaser may be repeatedly awaited.
36	<	* Method {@code arriveAndAwaitAdvance} has effect analogous to
37	<	* {@code CyclicBarrier.await}.  However, Phasers separate two
38	<	* aspects of coordination, that may also be invoked independently:
20	>	* <p> <b>Registration.</b> Unlike the case for other barriers, the
21	>	* number of parties <em>registered</em> to synchronize on a phaser
22	>	* may vary over time.  Tasks may be registered at any time (using
23	>	* methods {@link #register}, {@link #bulkRegister}, or forms of
24	>	* constructors establishing initial numbers of parties), and
25	>	* optionally deregistered upon any arrival (using {@link
26	>	* #arriveAndDeregister}).  As is the case with most basic
27	>	* synchronization constructs, registration and deregistration affect
28	>	* only internal counts; they do not establish any further internal
29	>	* bookkeeping, so tasks cannot query whether they are registered.
30	>	* (However, you can introduce such bookkeeping by subclassing this
31	>	* class.)
32	>	*
33	>	* <p> <b>Synchronization.</b> Like a {@code CyclicBarrier}, a {@code
34	>	* Phaser} may be repeatedly awaited.  Method {@link
35	>	* #arriveAndAwaitAdvance} has effect analogous to {@link
36	>	* java.util.concurrent.CyclicBarrier#await CyclicBarrier.await}. Each
37	>	* generation of a {@code Phaser} has an associated phase number. The
38	>	* phase number starts at zero, and advances when all parties arrive
39	>	* at the barrier, wrapping around to zero after reaching {@code
40	>	* Integer.MAX_VALUE}. The use of phase numbers enables independent
41	>	* control of actions upon arrival at a barrier and upon awaiting
42	>	* others, via two kinds of methods that may be invoked by any
43	>	* registered party:
44		*
45		* <ul>
46		*
47	<	*   <li> Arriving at a barrier. Methods {@code arrive} and
48	<	*       {@code arriveAndDeregister} do not block, but return
49	<	*       the phase value current upon entry to the method.
50	<	*
51	<	*   <li> Awaiting others. Method {@code awaitAdvance} requires an
52	<	*       argument indicating the entry phase, and returns when the
53	<	*       barrier advances to a new phase.
54	<	* </ul>
47	>	*   <li> <b>Arrival.</b> Methods {@link #arrive} and
48	>	*       {@link #arriveAndDeregister} record arrival at a
49	>	*       barrier. These methods do not block, but return an associated
50	>	*       <em>arrival phase number</em>; that is, the phase number of
51	>	*       the barrier to which the arrival applied. When the final
52	>	*       party for a given phase arrives, an optional barrier action
53	>	*       is performed and the phase advances.  Barrier actions,
54	>	*       performed by the party triggering a phase advance, are
55	>	*       arranged by overriding method {@link #onAdvance(int, int)},
56	>	*       which also controls termination. Overriding this method is
57	>	*       similar to, but more flexible than, providing a barrier
58	>	*       action to a {@code CyclicBarrier}.
59	>	*
60	>	*   <li> <b>Waiting.</b> Method {@link #awaitAdvance} requires an
61	>	*       argument indicating an arrival phase number, and returns when
62	>	*       the barrier advances to (or is already at) a different phase.
63	>	*       Unlike similar constructions using {@code CyclicBarrier},
64	>	*       method {@code awaitAdvance} continues to wait even if the
65	>	*       waiting thread is interrupted. Interruptible and timeout
66	>	*       versions are also available, but exceptions encountered while
67	>	*       tasks wait interruptibly or with timeout do not change the
68	>	*       state of the barrier. If necessary, you can perform any
69	>	*       associated recovery within handlers of those exceptions,
70	>	*       often after invoking {@code forceTermination}.  Phasers may
71	>	*       also be used by tasks executing in a {@link ForkJoinPool},
72	>	*       which will ensure sufficient parallelism to execute tasks
73	>	*       when others are blocked waiting for a phase to advance.
74		*
75	+	* </ul>
76		*
77	<	* <li> Barrier actions, performed by the task triggering a phase
78	<	* advance while others may be waiting, are arranged by overriding
79	<	* method {@code onAdvance}, that also controls termination.
80	<	* Overriding this method may be used to similar but more flexible
81	<	* effect as providing a barrier action to a CyclicBarrier.
82	<	*
83	<	* <li> Phasers may enter a <em>termination</em> state in which all
84	<	* actions immediately return without updating phaser state or waiting
85	<	* for advance, and indicating (via a negative phase value) that
86	<	* execution is complete.  Termination is triggered by executing the
87	<	* overridable {@code onAdvance} method that is invoked each time the
63	<	* barrier is about to be tripped. When a Phaser is controlling an
64	<	* action with a fixed number of iterations, it is often convenient to
65	<	* override this method to cause termination when the current phase
66	<	* number reaches a threshold. Method {@code forceTermination} is also
67	<	* available to abruptly release waiting threads and allow them to
68	<	* terminate.
77	>	* <p> <b>Termination.</b> A {@code Phaser} may enter a
78	>	* <em>termination</em> state in which all synchronization methods
79	>	* immediately return without updating phaser state or waiting for
80	>	* advance, and indicating (via a negative phase value) that execution
81	>	* is complete.  Termination is triggered when an invocation of {@code
82	>	* onAdvance} returns {@code true}.  As illustrated below, when
83	>	* phasers control actions with a fixed number of iterations, it is
84	>	* often convenient to override this method to cause termination when
85	>	* the current phase number reaches a threshold. Method {@link
86	>	* #forceTermination} is also available to abruptly release waiting
87	>	* threads and allow them to terminate.
88		*
89	<	* <li> Phasers may be tiered to reduce contention. Phasers with large
89	>	* <p> <b>Tiering.</b> Phasers may be <em>tiered</em> (i.e., arranged
90	>	* in tree structures) to reduce contention. Phasers with large
91		* numbers of parties that would otherwise experience heavy
92	<	* synchronization contention costs may instead be arranged in trees.
93	<	* This will typically greatly increase throughput even though it
94	<	* incurs somewhat greater per-operation overhead.
95	<	*
96	<	* <li> By default, {@code awaitAdvance} continues to wait even if
97	<	* the waiting thread is interrupted. And unlike the case in
98	<	* CyclicBarriers, exceptions encountered while tasks wait
99	<	* interruptibly or with timeout do not change the state of the
100	<	* barrier. If necessary, you can perform any associated recovery
101	<	* within handlers of those exceptions, often after invoking
102	<	* {@code forceTermination}.
103	<	*
104	<	* <li>Phasers ensure lack of starvation when used by ForkJoinTasks.
105	<	*
106	<	* </ul>
92	>	* synchronization contention costs may instead be set up so that
93	>	* groups of sub-phasers share a common parent.  This may greatly
94	>	* increase throughput even though it incurs greater per-operation
95	>	* overhead.
96	>	*
97	>	* <p><b>Monitoring.</b> While synchronization methods may be invoked
98	>	* only by registered parties, the current state of a phaser may be
99	>	* monitored by any caller.  At any given moment there are {@link
100	>	* #getRegisteredParties} parties in total, of which {@link
101	>	* #getArrivedParties} have arrived at the current phase ({@link
102	>	* #getPhase}).  When the remaining ({@link #getUnarrivedParties})
103	>	* parties arrive, the phase advances; thus, this value is always
104	>	* greater than zero if there are any registered parties.  The values
105	>	* returned by these methods may reflect transient states and so are
106	>	* not in general useful for synchronization control.  Method {@link
107	>	* #toString} returns snapshots of these state queries in a form
108	>	* convenient for informal monitoring.
109		*
110		* <p><b>Sample usages:</b>
111		*
112	<	* <p>A Phaser may be used instead of a {@code CountDownLatch} to control
113	<	* a one-shot action serving a variable number of parties. The typical
114	<	* idiom is for the method setting this up to first register, then
115	<	* start the actions, then deregister, as in:
112	>	* <p>A {@code Phaser} may be used instead of a {@code CountDownLatch}
113	>	* to control a one-shot action serving a variable number of
114	>	* parties. The typical idiom is for the method setting this up to
115	>	* first register, then start the actions, then deregister, as in:
116		*
117		*  <pre> {@code
118	<	* void runTasks(List<Runnable> list) {
118	>	* void runTasks(List<Runnable> tasks) {
119		*   final Phaser phaser = new Phaser(1); // "1" to register self
120	<	*   for (Runnable r : list) {
120	>	*   // create and start threads
121	>	*   for (Runnable task : tasks) {
122		*     phaser.register();
123		*     new Thread() {
124		*       public void run() {
125		*         phaser.arriveAndAwaitAdvance(); // await all creation
126	<	*         r.run();
104	<	*         phaser.arriveAndDeregister();   // signal completion
126	>	*         task.run();
127		*       }
128		*     }.start();
129		*   }
130		*
131	<	*   doSomethingOnBehalfOfWorkers();
132	<	*   phaser.arrive(); // allow threads to start
111	<	*   int p = phaser.arriveAndDeregister(); // deregister self  ...
112	<	*   p = phaser.awaitAdvance(p); // ... and await arrival
113	<	*   otherActions(); // do other things while tasks execute
114	<	*   phaser.awaitAdvance(p); // await final completion
131	>	*   // allow threads to start and deregister self
132	>	*   phaser.arriveAndDeregister();
133		* }}</pre>
134		*
135		* <p>One way to cause a set of threads to repeatedly perform actions
136		* for a given number of iterations is to override {@code onAdvance}:
137		*
138		*  <pre> {@code
139	<	* void startTasks(List<Runnable> list, final int iterations) {
139	>	* void startTasks(List<Runnable> tasks, final int iterations) {
140		*   final Phaser phaser = new Phaser() {
141	<	*     public boolean onAdvance(int phase, int registeredParties) {
141	>	*     protected boolean onAdvance(int phase, int registeredParties) {
142		*       return phase >= iterations || registeredParties == 0;
143		*     }
144		*   };
145		*   phaser.register();
146	<	*   for (Runnable r : list) {
146	>	*   for (Runnable task : tasks) {
147		*     phaser.register();
148		*     new Thread() {
149		*       public void run() {
150		*         do {
151	<	*           r.run();
151	>	*           task.run();
152		*           phaser.arriveAndAwaitAdvance();
153		*         } while(!phaser.isTerminated();
154		*       }
#	Line 139 | Line 157 | import java.util.concurrent.locks.LockSu
157		*   phaser.arriveAndDeregister(); // deregister self, don't wait
158		* }}</pre>
159		*
160	<	* <p> To create a set of tasks using a tree of Phasers,
160	>	* If the main task must later await termination, it
161	>	* may re-register and then execute a similar loop:
162	>	* <pre> {@code
163	>	*   // ...
164	>	*   phaser.register();
165	>	*   while (!phaser.isTerminated())
166	>	*     phaser.arriveAndAwaitAdvance();
167	>	* }</pre>
168	>	*
169	>	* Related constructions may be used to await particular phase numbers
170	>	* in contexts where you are sure that the phase will never wrap around
171	>	* {@code Integer.MAX_VALUE}. For example:
172	>	*
173	>	* <pre> {@code
174	>	*   void awaitPhase(Phaser phaser, int phase) {
175	>	*     int p = phaser.register(); // assumes caller not already registered
176	>	*     while (p < phase) {
177	>	*       if (phaser.isTerminated())
178	>	*         // ... deal with unexpected termination
179	>	*       else
180	>	*         p = phaser.arriveAndAwaitAdvance();
181	>	*     }
182	>	*     phaser.arriveAndDeregister();
183	>	*   }
184	>	* }</pre>
185	>	*
186	>	*
187	>	* <p>To create a set of tasks using a tree of phasers,
188		* you could use code of the following form, assuming a
189	<	* Task class with a constructor accepting a Phaser that
189	>	* Task class with a constructor accepting a phaser that
190		* it registers for upon construction:
191		*  <pre> {@code
192		* void build(Task[] actions, int lo, int hi, Phaser b) {
#	Line 171 | Line 216 | import java.util.concurrent.locks.LockSu
216		*
217		* <p><b>Implementation notes</b>: This implementation restricts the
218		* maximum number of parties to 65535. Attempts to register additional
219	<	* parties result in IllegalStateExceptions. However, you can and
219	>	* parties result in {@code IllegalStateException}. However, you can and
220		* should create tiered phasers to accommodate arbitrarily large sets
221		* of participants.
222		*
#	Line 249 | Line 294 | public class Phaser {
294		private final Phaser parent;
295
296		/**
297	<	* The root of Phaser tree. Equals this if not in a tree.  Used to
297	>	* The root of phaser tree. Equals this if not in a tree.  Used to
298		* support faster state push-down.
299		*/
300		private final Phaser root;
#	Line 300 | Line 345 | public class Phaser {
345		}
346
347		/**
348	<	* Creates a new Phaser without any initially registered parties,
348	>	* Creates a new phaser without any initially registered parties,
349		* initial phase number 0, and no parent. Any thread using this
350	<	* Phaser will need to first register for it.
350	>	* phaser will need to first register for it.
351		*/
352		public Phaser() {
353		this(null);
354		}
355
356		/**
357	<	* Creates a new Phaser with the given numbers of registered
357	>	* Creates a new phaser with the given numbers of registered
358		* unarrived parties, initial phase number 0, and no parent.
359		*
360		* @param parties the number of parties required to trip barrier
#	Line 321 | Line 366 | public class Phaser {
366		}
367
368		/**
369	<	* Creates a new Phaser with the given parent, without any
369	>	* Creates a new phaser with the given parent, without any
370		* initially registered parties. If parent is non-null this phaser
371		* is registered with the parent and its initial phase number is
372		* the same as that of parent phaser.
#	Line 341 | Line 386 | public class Phaser {
386		}
387
388		/**
389	<	* Creates a new Phaser with the given parent and numbers of
389	>	* Creates a new phaser with the given parent and numbers of
390		* registered unarrived parties. If parent is non-null, this phaser
391		* is registered with the parent and its initial phase number is
392		* the same as that of parent phaser.
#	Line 368 | Line 413 | public class Phaser {
413		/**
414		* Adds a new unarrived party to this phaser.
415		*
416	<	* @return the current barrier phase number upon registration
416	>	* @return the arrival phase number to which this registration applied
417		* @throws IllegalStateException if attempting to register more
418		* than the maximum supported number of parties
419		*/
#	Line 380 | Line 425 | public class Phaser {
425		* Adds the given number of new unarrived parties to this phaser.
426		*
427		* @param parties the number of parties required to trip barrier
428	<	* @return the current barrier phase number upon registration
428	>	* @return the arrival phase number to which this registration applied
429		* @throws IllegalStateException if attempting to register more
430		* than the maximum supported number of parties
431		*/
#	Line 415 | Line 460 | public class Phaser {
460
461		/**
462		* Arrives at the barrier, but does not wait for others.  (You can
463	<	* in turn wait for others via {@link #awaitAdvance}).
463	>	* in turn wait for others via {@link #awaitAdvance}).  It is an
464	>	* unenforced usage error for an unregistered party to invoke this
465	>	* method.
466		*
467	<	* @return the barrier phase number upon entry to this method, or a
421	<	* negative value if terminated
467	>	* @return the arrival phase number, or a negative value if terminated
468		* @throws IllegalStateException if not terminated and the number
469		* of unarrived parties would become negative
470		*/
#	Line 463 | Line 509 | public class Phaser {
509		}
510
511		/**
512	<	* Arrives at the barrier, and deregisters from it, without
513	<	* waiting for others. Deregistration reduces number of parties
512	>	* Arrives at the barrier and deregisters from it without waiting
513	>	* for others. Deregistration reduces the number of parties
514		* required to trip the barrier in future phases.  If this phaser
515		* has a parent, and deregistration causes this phaser to have
516	<	* zero parties, this phaser is also deregistered from its parent.
516	>	* zero parties, this phaser also arrives at and is deregistered
517	>	* from its parent.  It is an unenforced usage error for an
518	>	* unregistered party to invoke this method.
519		*
520	<	* @return the current barrier phase number upon entry to
473	<	* this method, or a negative value if terminated
520	>	* @return the arrival phase number, or a negative value if terminated
521		* @throws IllegalStateException if not terminated and the number
522		* of registered or unarrived parties would become negative
523		*/
#	Line 520 | Line 567 | public class Phaser {
567
568		/**
569		* Arrives at the barrier and awaits others. Equivalent in effect
570	<	* to {@code awaitAdvance(arrive())}.  If you instead need to
571	<	* await with interruption of timeout, and/or deregister upon
572	<	* arrival, you can arrange them using analogous constructions.
570	>	* to {@code awaitAdvance(arrive())}.  If you need to await with
571	>	* interruption or timeout, you can arrange this with an analogous
572	>	* construction using one of the other forms of the awaitAdvance
573	>	* method.  If instead you need to deregister upon arrival use
574	>	* {@code arriveAndDeregister}. It is an unenforced usage error
575	>	* for an unregistered party to invoke this method.
576		*
577	<	* @return the phase on entry to this method
577	>	* @return the arrival phase number, or a negative number if terminated
578		* @throws IllegalStateException if not terminated and the number
579		* of unarrived parties would become negative
580		*/
#	Line 533 | Line 583 | public class Phaser {
583		}
584
585		/**
586	<	* Awaits the phase of the barrier to advance from the given
587	<	* value, or returns immediately if argument is negative or this
588	<	* barrier is terminated.
589	<	*
590	<	* @param phase the phase on entry to this method
591	<	* @return the phase on exit from this method
586	>	* Awaits the phase of the barrier to advance from the given phase
587	>	* value, returning immediately if the current phase of the
588	>	* barrier is not equal to the given phase value or this barrier
589	>	* is terminated.  It is an unenforced usage error for an
590	>	* unregistered party to invoke this method.
591	>	*
592	>	* @param phase an arrival phase number, or negative value if
593	>	* terminated; this argument is normally the value returned by a
594	>	* previous call to {@code arrive} or its variants
595	>	* @return the next arrival phase number, or a negative value
596	>	* if terminated or argument is negative
597		*/
598		public int awaitAdvance(int phase) {
599		if (phase < 0)
#	Line 554 | Line 609 | public class Phaser {
609		}
610
611		/**
612	<	* Awaits the phase of the barrier to advance from the given
613	<	* value, or returns immediately if argument is negative or this
614	<	* barrier is terminated, or throws InterruptedException if
615	<	* interrupted while waiting.
616	<	*
617	<	* @param phase the phase on entry to this method
618	<	* @return the phase on exit from this method
612	>	* Awaits the phase of the barrier to advance from the given phase
613	>	* value, throwing {@code InterruptedException} if interrupted
614	>	* while waiting, or returning immediately if the current phase of
615	>	* the barrier is not equal to the given phase value or this
616	>	* barrier is terminated. It is an unenforced usage error for an
617	>	* unregistered party to invoke this method.
618	>	*
619	>	* @param phase an arrival phase number, or negative value if
620	>	* terminated; this argument is normally the value returned by a
621	>	* previous call to {@code arrive} or its variants
622	>	* @return the next arrival phase number, or a negative value
623	>	* if terminated or argument is negative
624		* @throws InterruptedException if thread interrupted while waiting
625		*/
626		public int awaitAdvanceInterruptibly(int phase)
#	Line 577 | Line 637 | public class Phaser {
637		}
638
639		/**
640	<	* Awaits the phase of the barrier to advance from the given value
641	<	* or the given timeout elapses, or returns immediately if
642	<	* argument is negative or this barrier is terminated.
643	<	*
644	<	* @param phase the phase on entry to this method
645	<	* @return the phase on exit from this method
640	>	* Awaits the phase of the barrier to advance from the given phase
641	>	* value or the given timeout to elapse, throwing {@code
642	>	* InterruptedException} if interrupted while waiting, or
643	>	* returning immediately if the current phase of the barrier is
644	>	* not equal to the given phase value or this barrier is
645	>	* terminated.  It is an unenforced usage error for an
646	>	* unregistered party to invoke this method.
647	>	*
648	>	* @param phase an arrival phase number, or negative value if
649	>	* terminated; this argument is normally the value returned by a
650	>	* previous call to {@code arrive} or its variants
651	>	* @param timeout how long to wait before giving up, in units of
652	>	*        {@code unit}
653	>	* @param unit a {@code TimeUnit} determining how to interpret the
654	>	*        {@code timeout} parameter
655	>	* @return the next arrival phase number, or a negative value
656	>	* if terminated or argument is negative
657		* @throws InterruptedException if thread interrupted while waiting
658		* @throws TimeoutException if timed out while waiting
659		*/
#	Line 636 | Line 707 | public class Phaser {
707		}
708
709		/**
639	–	* Returns {@code true} if the current phase number equals the given phase.
640	–	*
641	–	* @param phase the phase
642	–	* @return {@code true} if the current phase number equals the given phase
643	–	*/
644	–	public final boolean hasPhase(int phase) {
645	–	return phaseOf(getReconciledState()) == phase;
646	–	}
647	–
648	–	/**
710		* Returns the number of parties registered at this barrier.
711		*
712		* @return the number of parties
#	Line 655 | Line 716 | public class Phaser {
716		}
717
718		/**
719	<	* Returns the number of parties that have arrived at the current
720	<	* phase of this barrier.
719	>	* Returns the number of registered parties that have arrived at
720	>	* the current phase of this barrier.
721		*
722		* @return the number of arrived parties
723		*/
#	Line 675 | Line 736 | public class Phaser {
736		}
737
738		/**
739	<	* Returns the parent of this phaser, or null if none.
739	>	* Returns the parent of this phaser, or {@code null} if none.
740		*
741	<	* @return the parent of this phaser, or null if none
741	>	* @return the parent of this phaser, or {@code null} if none
742		*/
743		public Phaser getParent() {
744		return parent;
#	Line 706 | Line 767 | public class Phaser {
767		* Overridable method to perform an action upon phase advance, and
768		* to control termination. This method is invoked whenever the
769		* barrier is tripped (and thus all other waiting parties are
770	<	* dormant). If it returns true, then, rather than advance the
771	<	* phase number, this barrier will be set to a final termination
772	<	* state, and subsequent calls to {@code isTerminated} will
773	<	* return true.
770	>	* dormant). If it returns {@code true}, then, rather than advance
771	>	* the phase number, this barrier will be set to a final
772	>	* termination state, and subsequent calls to {@link #isTerminated}
773	>	* will return true.
774		*
775	<	* <p> The default version returns true when the number of
775	>	* <p>The default version returns {@code true} when the number of
776		* registered parties is zero. Normally, overrides that arrange
777		* termination for other reasons should also preserve this
778		* property.
779		*
780	<	* <p> You may override this method to perform an action with side
780	>	* <p>You may override this method to perform an action with side
781		* effects visible to participating tasks, but it is in general
782		* only sensible to do so in designs where all parties register
783	<	* before any arrive, and all {@code awaitAdvance} at each phase.
784	<	* Otherwise, you cannot ensure lack of interference. In
785	<	* particular, this method may be invoked more than once per
725	<	* transition if other parties successfully register while the
726	<	* invocation of this method is in progress, thus postponing the
727	<	* transition until those parties also arrive, re-triggering this
728	<	* method.
783	>	* before any arrive, and all {@link #awaitAdvance} at each phase.
784	>	* Otherwise, you cannot ensure lack of interference from other
785	>	* parties during the invocation of this method.
786		*
787		* @param phase the phase number on entering the barrier
788		* @param registeredParties the current number of registered parties

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