问jheatbugs-2001-03-28中某些代码

sybbk

HeatbugModelSwarm中buildActions部分，3个try分别是做什么？查了下refbook-java-2.2，解释太简略，还是不懂，高手指点，谢谢！代码如下：

5 z: r' q: j$ u3 D public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
7 @7 r, E. O; j: Q4 @8 q0 [) w    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
- A: Y8 V2 c/ J# P; F8 f; {    // object, or ForEach object in a collection.
, B# `, o! f; c( W  `7 V        
. F$ m( t9 E6 F) p2 j# v8 e3 V    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
# l$ N5 {9 B' V. C        
4 ~3 f. O* Z# P! R* E    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
- ]* \, g0 p; L' t    // randomize the order in which the bugs actually run
* w' ^- i" n% S- b2 i8 f7 s6 [: K    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
$ e1 m* I! c( a- @( n        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
$ F8 W! z8 c" v5 L% D7 q# Y   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
0 _0 I, ~' g4 f% E; C- ~    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

7 g- t: T% a- s" l    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
5 R. d( o8 T4 L/ }' g5 j) p* l- v      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
0 i* v: z" `# \+ u        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
; z. E' U- q9 ]         new FCallImpl (this, proto, sel,
. ]; f/ [, n( O& P0 z" M. p                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
4 v" N. i9 U0 u- i7 m+ y. }1 m   
    syncUpdateOrder ();

3 h( G( J- o/ C! {    try {
      modelActions.createActionTo$message
  f1 F+ z7 g$ \6 o$ _; @$ n$ u        (heat, new Selector (heat.getClass (), "updateLattice", false));
3 h4 D8 _+ r0 Q: r    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
1 s3 W4 f" ?9 d" c    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
9 {) n7 a! Y( ~$ X1 S    // has no notion of time. In order to have it executed in
$ |+ ^2 p4 Q% ]/ j) C" k! C8 O    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
4 ]0 K' f  p- G* Z    // the beginning of the loop.

6 L8 j  W1 X2 }2 H5 E    // This is a simple schedule, with only one action that is
$ K7 g5 U: P* Z* J9 f8 U    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
' t8 L! v; L3 i5 V8 T! P        
1 G$ w  ?  u9 c* j  A: g7 F$ J1 Y    return this;
4 Z9 s) Q9 Y6 v  A" x; X: ]  }