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：

3 X" w% z$ \" [* {' `. m( Z/ f public Object buildActions () {
    super.buildActions();
   
) f: ~! f# j9 a2 @8 @    // 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
! u  U6 l6 g* D2 {6 i+ R  k- C: _    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
* h5 L% O$ w1 K+ x        
3 b; j7 U6 [! C7 G# W* K    // 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
3 u5 Y1 L/ L, }" l, Y, W    // significant!
" r+ `+ {/ g! o/ u/ w$ g        
  Q1 a3 Q3 {. P- w" o    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
2 m7 D  A" o. D4 z) V$ u    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
: q) ~. D9 M1 p5 q    // list from timestep to timestep
; m" X8 S. C5 i7 N        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
! |6 S/ j# C, ^' Q    // order of iteration through the `heatbugList' will be
4 L6 r! Z  h# j- y) e' l6 g    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
9 t* Y8 c! h/ S+ {" h+ a    modelActions = new ActionGroupImpl (getZone ());
# D; N' \8 ?0 \. C
    try {
      modelActions.createActionTo$message
' U$ N3 Y* [( S/ G0 `6 j        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
9 b7 f" R7 h# R: ]: r. ^      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
* A& i# D9 H  {4 \      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
2 C- c/ i. x4 i1 j        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
9 X. ~( q# o7 ]  ^) M    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
# i/ |1 J3 _: x. Y    syncUpdateOrder ();
5 F- }  v. z6 R  j$ A& {6 K
$ o) V/ @; Z* U7 q* }    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
+ r6 a4 }# @: ?$ u3 \( G' A# T8 f/ E      System.err.println("Exception updateLattice: " + e.getMessage ());
" Q, V: T1 v! b, ~" `  k    }
+ W( i3 F" _* B5 z/ A, T- ~8 f        
5 S% {! }/ v5 K; a7 S2 Y    // Then we create a schedule that executes the
8 Y8 V( D. g2 Q    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
7 U9 `1 A2 C3 g; b  N    // schedule has a repeat interval of 1, it will loop every
, z  z  Q5 n6 h) k6 P" \    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

' K4 w- w# J$ a, z( f$ \) h    // This is a simple schedule, with only one action that is
+ S: p& C5 Y2 M& ~1 o3 D6 ]9 p    // just repeated every time. See jmousetrap for more
- ^8 `& H0 E% e6 s/ r% z    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
# k+ e3 p6 v# \2 H    return this;
  }