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：
9 o  c4 x; j" N0 Z$ u
2 o# W2 z/ C4 a2 ]2 h) L! q$ e- O1 u public Object buildActions () {
( v, R; K! ~5 d& t: ]    super.buildActions();
   
    // Create the list of simulation actions. We put these in
1 k+ ]+ W- T6 L+ x9 T+ Y    // an action group, because we want these actions to be
" ~, L) m9 p- W. H& K    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
" Q: I1 b7 a! z    // object, or ForEach object in a collection.
        
) X+ @8 c1 n  ]; i    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
) Z, u+ u7 F& \0 d  ~    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
' L! y2 W0 ^: |    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
1 ~0 M8 z9 m/ E7 H3 Y    // systematic bias in the iteration throught the heatbug
8 w1 K2 \) a! z& W    // list from timestep to timestep
        
3 ]& s1 A, z' r4 V% r    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
6 Y* d+ l7 l. q, J; c: j9 n+ f+ q    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
7 o8 e& X* _4 v0 g    modelActions = new ActionGroupImpl (getZone ());
( j  [+ [5 I  V3 R
  Y2 X% B* W* q5 P) P    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
: C- ^& _$ d. M( P) o$ u      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

! f- r: n. B8 q1 t- m# _( F+ i7 W    try {
8 }& T3 b+ v: e( u/ q1 M2 f7 E      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
6 F! H4 i+ d% }/ N        modelActions.createFActionForEachHomogeneous$call
" j7 K4 h" l# [* @        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
7 @) h( Y0 ~* n9 v6 [    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
6 q, o7 t4 i9 y4 h" u& y5 ?- L   
; w* m3 f& p' o3 A    syncUpdateOrder ();
2 }/ H; ~$ w$ b  K! g& a7 J
    try {
) e  `& E) X- d! t' J# l      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
- T) x( y# z* _& c7 A    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
  O& a0 ]& l3 {' z5 V    // Then we create a schedule that executes the
* X( Q% b+ s7 }/ z8 Y1 s) }8 g, {    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
) n' Z: l. H, I$ I& O* E2 n    // 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
    // the beginning of the loop.

    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
, F  [; P# ?" D) \8 Y    // complicated schedules.
0 U- |2 P3 \4 q+ }3 w/ B$ d3 }  k  
    modelSchedule = new ScheduleImpl (getZone (), 1);
6 \9 s9 X% b2 g# Y2 a% S    modelSchedule.at$createAction (0, modelActions);
        
4 _2 b/ y8 Z4 d( }$ Z    return this;
  }