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：

( h0 Q$ g( l5 x+ p* V5 H public Object buildActions () {
    super.buildActions();
   
3 p, A, F1 V7 y    // 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
; h0 d" T5 w* y8 e% M    // take no (simulated) time. The M(foo) means "The message
: t1 D/ s. G2 @! o: P% V1 p    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
: `4 f0 K; P% p& f& `        
    // 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!
" X+ G% Z/ G0 O: h8 }        
    // Note also, that with the additional
$ j  F  D9 |3 F. ?4 b" T! s    // `randomizeHeatbugUpdateOrder' Boolean flag we can
% h5 `6 M- V0 D+ g0 U' T: [    // randomize the order in which the bugs actually run
8 q9 p& K( D" _8 l, z2 h9 H    // their step rule.  This has the effect of removing any
, \& P# y; @+ P& E8 C  j    // systematic bias in the iteration throught the heatbug
' w8 D' _9 E( l' y& T    // list from timestep to timestep
5 Q) h. w$ }; Z9 y1 u4 `2 A        
7 P! y. K  v( u    // 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).
$ G  s. i+ ]) X3 _! i+ c2 e0 Z   
4 S( s* F8 N* b' i  [1 N    modelActions = new ActionGroupImpl (getZone ());

    try {
! x' e& L+ W' d( h* l, E% K9 ~. R+ y      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
& n6 x- T2 c$ z# t    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
3 w  R% Y" }( n2 y% U) r( r) E
    try {
: S% B0 Q5 O$ B+ y4 f      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
7 R# z' Y* a( W5 j. _$ p- J        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
% t" ~" U0 T$ e% ?$ e5 M        (heatbugList,
         new FCallImpl (this, proto, sel,
" [! H. Q1 T+ i) }+ w6 W3 w6 S                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();
6 z9 i& v2 r6 H" a' W
    try {
3 j- i0 Q( M2 W7 B' L' O      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
8 ]  j( b3 S- {# T3 N8 f" h0 S      System.err.println("Exception updateLattice: " + e.getMessage ());
" U* g: r0 `$ G$ m+ |  L; ?+ b    }
        
3 T9 w5 W+ e; I% t' t( a6 v, s7 E    // Then we create a schedule that executes the
# Z, G5 S) r8 Q! U8 h# [7 Z    // modelActions. modelActions is an ActionGroup, by itself it
& t2 b  ?+ L4 A6 g4 _    // has no notion of time. In order to have it executed in
8 n4 g9 j, z# q* }5 U    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
! a. e+ y2 Z' y/ G' E  E  Q    // 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
1 O1 x, {( J* r) p1 `! y    // just repeated every time. See jmousetrap for more
" v, ]$ v0 f  j: L    // complicated schedules.
3 U! R- S2 L2 F" t0 A1 J  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
9 @$ d: P1 s& B" d9 j: A# f  }