pps. The following is more elegant and also works:
static Boolean[] testInit = new Boolean[1];
private void initialize() {
if (testInit[0] != null) {
while (!testInit[0].booleanValue()) {
try{
Thread.sleep(10);
} catch(Exception e) {
System.out.println("geodesic constructor error "+e);
}
}
return;
}
testInit[0] = Boolean.FALSE;
...
System.out.println("geodesic initialization completed");
testInit[0] = Boolean.TRUE;
}
It takes advantage of the fact that static testInit[0] has THREE
possible values: null, false, and true.
This is what I'm going with for now.
Bob
Bob Hanson wrote:
>One revision -- the prev. code only ensures synchronicity, not
>once-through and synchronized. This is correct:
>
> private void initialize() {
> //System.out.println("geodesic init " + testInit + " started");
> if (testInit.x++ > 0) {
> while (testInit.y == 0) {
>Bob Hanson wrote:
>
>
>
>>OK, I've identified the problem:
>>
>>1) In Geodesics we see:
>>
>>Geodesic3D(Graphics3D g3d) {
>> this.g3d = g3d;
>> if (vertexCounts == null)
>> initialize();
>> }
>>
>>
>> private synchronized void initialize() {
>> if (vertexCounts != null) {
>> return;
>> }
>> vertexCounts = new short[maxLevel];
>> .....
>>}
>>
>>
>>Fine, this APPEARS to say, "If some other thread has not STARTED to
>>initialize the geodesic normals system, go ahead and initialize." That's
>>important, because only the first thread should initialize. Note that
>>this is not "the first thread from this web page loading" but "the first
>>thread from any page from this server (or, perhaps, from this server
>>using this Jar file, I suspect) since the Jmol applet has first been
>>used in this browser session."
>>
>>2) It turns out there are two problems with this:
>>
>>Problem 1: It is NOT "Wait here until some other thread has FINISHED
>>initializing the geodesci normals system." Miguel is saying, "Oh
>>[EMAIL PROTECTED]" right now. Because while one thread has STARTED -- but not
>>FINISHED -- initializing the normals system, another thread has bypassed
>>initialization and is fast into creating an isosurface that needs that
>>system.
>>
>>Problem 2: You (apparently) cannot use synchronization within a
>>constructor. At least in Firefox (the only browser I tested this on) I
>>changed the above to this:
>>
>> Geodesic3D(Graphics3D g3d) {
>> this.g3d = g3d;
>> String msg = "Geodesecs "+ System.currentTimeMillis();
>> System.out.println(msg+" 0");
>> initialize();
>> System.out.println(msg+" 1");
>> }
>>
>> private synchronized void initialize() {
>> System.out.println("geodesic init");
>> if (vertexCounts != null) {
>> System.out.println("geodesic init skipped");
>> return;
>> }
>> System.out.println("geodesic init continuing");
>> vertexCounts = new short[maxLevel];
>> ...
>> for(int i=0;i++<1000000;){String s="";} // just to slow it down
>> System.out.println("geodesic init 1");
>> }
>>
>>Now, you might expect to see the threads wait for the synchronization,
>>right? But NOOOO! I get for a page displaying eight orbitals [added
>>comments in brackets]:
>>
>>Geodesecs 1149943353546 0
>>Geodesecs 1149943353546 0
>>Geodesecs 1149943353546 0
>>Geodesecs 1149943353546 0
>>Geodesecs 1149943353546 0
>>Geodesecs 1149943353546 0
>>
>>[that's six of them]
>>
>>geodesic init
>>geodesic init
>>geodesic init
>>geodesic init
>>Geodesecs 1149943353546 0
>>geodesic init
>>geodesic init
>>
>>[how can this be -- they are synchronized, no? Ah, but they are
>>CONSTRUCTORS!]
>>
>>geodesic init continuing
>>geodesic init continuing
>>geodesic init continuing
>>geodesic init continuing
>>
>>[you're kidding, right? ALL continuing? What happened to the sync?]
>>
>>geodesic init
>>geodesic init continuing
>>geodesic init continuing
>>
>>[#$&[EMAIL PROTECTED]
>>
>>geodesic init 1
>>
>>[at this point 7 contructors have started, 7 have started into
>>initialize() in full, 5 are CONTINUING, one has completed initialize();
>>one is unaccounted for, and none have finished construction of Geodesics.]
>>
>>Could not instantiate wrappedApplet classorg.jmol.applet.Jmol
>>java.lang.NullPointerException
>> at org.jmol.g3d.Geodesic3D.getVertex(Geodesic3D.java:406)
>> at org.jmol.g3d.Geodesic3D.quadruple(Geodesic3D.java:296)
>> at org.jmol.g3d.Geodesic3D.initialize(Geodesic3D.java:216)
>> at org.jmol.g3d.Geodesic3D.<init>(Geodesic3D.java:180)
>> at org.jmol.g3d.Graphics3D.<init>(Graphics3D.java:104)
>> at org.jmol.viewer.Viewer.<init>(Viewer.java:121)
>> at org.jmol.viewer.Viewer.allocateViewer(Viewer.java:143)
>> at org.jmol.api.JmolViewer.allocateViewer(JmolViewer.java:51)
>> at org.jmol.applet.Jmol.initWindows(Jmol.java:182)
>> at org.jmol.applet.Jmol.init(Jmol.java:145)
>> at
>>org.jmol.appletwrapper.WrappedAppletLoader.run(WrappedAppletLoader.java:51)
>>
>>[There it is!!! No surprise here, I guess.]
>>
>>geodesic init 1
>>geodesic init skipped
>>geodesic init 1
>>geodesic init 1
>>
>>[3 more have done the FULL initialization; one did skip]
>>
>>Geodesecs 1149943353546 1
>>Geodesecs 1149943353546 1
>>Geodesecs 1149943353671 0
>>Geodesecs 1149943353546 1
>>Geodesecs 1149943353546 1
>>
>>[ok, the first 4 threads have completed construction of Geodesics; #8 is
>>finally getting going]
>>
>>Could not instantiate wrappedApplet classorg.jmol.applet.Jmol
>>java.lang.NullPointerException
>> at org.jmol.g3d.Geodesic3D.getVertex(Geodesic3D.java:406)
>> at org.jmol.g3d.Geodesic3D.quadruple(Geodesic3D.java:295)
>> at org.jmol.g3d.Geodesic3D.initialize(Geodesic3D.java:216)
>> at org.jmol.g3d.Geodesic3D.<init>(Geodesic3D.java:180)
>> at org.jmol.g3d.Graphics3D.<init>(Graphics3D.java:104)
>> at org.jmol.viewer.Viewer.<init>(Viewer.java:121)
>> at org.jmol.viewer.Viewer.allocateViewer(Viewer.java:143)
>> at org.jmol.api.JmolViewer.allocateViewer(JmolViewer.java:51)
>> at org.jmol.applet.Jmol.initWindows(Jmol.java:182)
>> at org.jmol.applet.Jmol.init(Jmol.java:145)
>> at
>>org.jmol.appletwrapper.WrappedAppletLoader.run(WrappedAppletLoader.java:51)
>>
>>[argh!]
>>
>>geodesic init
>>geodesic init skipped
>>Geodesecs 1149943353671 1
>>
>>[#8 skips all initialization]
>>
>>Geodesecs 1149943353546 1
>>
>>[six completions; two errors; page shows orbitals 1,2,3,4,5, and 7, but
>>not 6 or 8]
>>
>>
>>THAT's the problem. I leave it to Miguel to tell us the elegant
>>solution. Mine is a classic no-synchronize entry/exit flag system using
>>a static boolean array:
>>
>> Geodesic3D(Graphics3D g3d) {
>> this.g3d = g3d;
>> String msg = "Geodesecs "+ System.currentTimeMillis();
>> System.out.println(msg+" 0");
>> initialize();
>> System.out.println(msg+" 1");
>> }
>>
>> static Point3i testInit = new Point3i();
>> private void initialize() {
>> System.out.println("geodesic init " + testInit + " started");
>> if (testInit.x++ > 0 && testInit.y == 0) {
>> while (testInit.y == 0) {
>> try{
>> Thread.sleep(10);
>> } catch(Exception e) {
>> System.out.println("geodesic error "+e);
>> }
>> System.out.println("geodesic init "+ testInit + " waiting");
>> }
>> System.out.println("geodesic init skipped");
>> return;
>> }
>> System.out.println("geodesic init " + testInit + " continuing");
>>...
>> System.out.println("geodesic init " + testInit + " completed");
>> ++testInit.y;
>> }
>>
>>Note that this takes advantage of the fact that Point3i is an object
>>that allows storage of two values and that, though static, allows for
>>the modification of these values. I'm just using testInit.x and
>>testInit.y. I now get:
>>
>>Geodesecs 1149949067812 0
>>geodesic init (0, 0, 0) started
>>geodesic init (1, 0, 0) continuing
>>Geodesecs 1149949067843 0
>>geodesic init (1, 0, 0) started
>>Geodesecs 1149949067843 0
>>geodesic init (2, 0, 0) started
>>Geodesecs 1149949067843 0
>>geodesic init (3, 0, 0) started
>>Geodesecs 1149949067843 0
>>geodesic init (4, 0, 0) started
>>Geodesecs 1149949067843 0
>>geodesic init (5, 0, 0) started
>>geodesic init (6, 0, 0) waiting
>>geodesic init (6, 0, 0) waiting
>>geodesic init (6, 0, 0) waiting
>>geodesic init (6, 0, 0) waiting
>>Geodesecs 1149949067843 0
>>geodesic init (6, 0, 0) started
>>geodesic init (7, 0, 0) waiting
>>Geodesecs 1149949067843 0
>>geodesic init (7, 0, 0) started
>>geodesic init (8, 0, 0) completed
>>Geodesecs 1149949067812 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>geodesic init (8, 1, 0) waiting
>>geodesic init skipped
>>Geodesecs 1149949067843 1
>>
>>
>>That's it! I see 8 orbitals now, and only one full initialization.
>>No synchronization.
>>Comments?
>>
>>Bob
>>
>>
>>
>>_______________________________________________
>>Jmol-developers mailing list
>>[email protected]
>>https://lists.sourceforge.net/lists/listinfo/jmol-developers
>>
>>
>>
>>
>
>
>
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