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：

0 n4 Q5 e' s( ?' L8 R public Object buildActions () {
( J  ~; v: n& Z  l8 K    super.buildActions();
5 i, ?  z3 m) X& z+ T   
( _' t! U! o2 ?, b* s- y5 R    // Create the list of simulation actions. We put these in
- I, @/ m- E, j0 `    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
% k8 Y- b+ u. Z+ z) }    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
0 m* E4 }: s  h. j        
; F0 T% R( A- Q2 _, A    // 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!
" y: D9 Q) }/ u% W3 h; I        
    // Note also, that with the additional
' S5 ~, }; D+ K+ Z    // `randomizeHeatbugUpdateOrder' Boolean flag we can
4 e3 t. i, t" o# @' y4 p/ r# h    // randomize the order in which the bugs actually run
% _0 x* g8 v+ M, b3 Q    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
& w, E9 ~  O5 ~; S    // list from timestep to timestep
        
    // 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
7 V2 r9 c" M: h# |, L( R    // indirectly by some other process).
2 N8 X5 M  l/ Z* |' G! J   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
7 t: ^* o3 b3 x        (heat, new Selector (heat.getClass (), "stepRule", false));
5 k6 |+ @3 r8 v; _    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
" `. c  y( B8 p" W7 ~& X    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
9 H/ p4 @) P1 j3 A5 m      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
$ _& g% y: @* A. o        modelActions.createFActionForEachHomogeneous$call
6 F  X, R) i6 r4 O. D. O+ i        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
$ S  T. h' ~1 B2 G/ G    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
% Y0 Q) _- {, T) u9 d( W1 \    syncUpdateOrder ();
) t7 X. A' I5 T- X. m# T0 w$ Z2 U
6 H; k7 _2 i, e  D: m! H  F    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
% F  U1 d+ S/ H8 k1 B' M8 U. e* G    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
- e7 K4 K* Y2 W  J# y! u' m    }
        
6 T; s1 m6 @- w# P  y    // Then we create a schedule that executes the
/ ?9 M. x. z3 \8 r    // 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
    // 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.

0 h4 Q7 n8 k  s8 Y0 x8 J- @7 a    // This is a simple schedule, with only one action that is
' |! m  q, Q0 c/ t% C) s    // just repeated every time. See jmousetrap for more
5 U, R0 d8 Y4 I' t    // complicated schedules.
  
  {/ r; {: d+ A) A4 A0 n$ Q    modelSchedule = new ScheduleImpl (getZone (), 1);
+ e# j7 |/ U. ^5 A4 `$ c4 W    modelSchedule.at$createAction (0, modelActions);
        
" X4 I4 ^; ^, k$ F+ `1 ]' _$ G    return this;
  }