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 E0 c# }. r% ~& h" Y& q public Object buildActions () {
* e6 I# g% T* B+ ?: V2 i    super.buildActions();
   
1 t3 j4 L1 c5 k5 _' E( m) f. }! }2 ]    // Create the list of simulation actions. We put these in
% B, t$ \+ v) D) P# l5 G    // an action group, because we want these actions to be
+ ~4 R* ~* N( z5 x6 w    // executed in a specific order, but these steps should
% u4 c6 f4 ]8 F- v3 }    // take no (simulated) time. The M(foo) means "The message
% Q2 P1 x! j# v" ?    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
' u: a, T6 F; I. t+ t7 M        
/ r+ p( q* W/ P, X7 L* k9 S    // 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
" d6 q6 N$ a+ i& K    // significant!
        
% e% e! v, b  _1 z6 j    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
8 k3 c, H! E1 Y& ]/ a/ L; u    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
/ Y' A% y* ?9 {- _6 g1 Z5 R+ t    // list from timestep to timestep
) A7 V; M* K4 G. Y( [# p        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
7 \1 I% a3 I9 H    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
+ q& O5 E' A: R" \/ P# ]2 p    modelActions = new ActionGroupImpl (getZone ());
3 G+ P) |3 N: [1 P1 e
1 S( u! a+ l0 A) O; y2 r: m& @1 t- X    try {
      modelActions.createActionTo$message
1 y( _, ?! _: ^) T        (heat, new Selector (heat.getClass (), "stepRule", false));
: G( X* ~: \5 L% e2 |$ K    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
) e8 F6 t. P' C$ s    }
' C( s: U: o' u) V$ v, I. I1 V
    try {
+ B/ _8 V7 ^& M- o! U3 X4 ~* X7 U. O      Heatbug proto = (Heatbug) heatbugList.get (0);
- o5 B1 G9 A* v- @3 J0 I  H      Selector sel =
% p) }+ q5 [) e, ]# ~, p        new Selector (proto.getClass (), "heatbugStep", false);
' x3 g1 w  e5 z5 e% _      actionForEach =
3 `0 M. B/ ?" ~" F" [- g: y% Y        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
# v/ e* H1 O' J7 ^3 h) h/ \) n                        new FArgumentsImpl (this, sel)));
0 O  K6 a( ~, m* o$ Y) y1 u    } catch (Exception e) {
      e.printStackTrace (System.err);
. v# m, f$ V8 F8 E    }
   
' {0 l& j7 `1 E# a' E0 e    syncUpdateOrder ();

    try {
$ j* z' t5 i6 I3 P+ P. \* W      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
  ~5 B- Z1 w8 p5 s/ x% ^6 |$ g. O    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
" j- X1 ^7 ~+ H8 ~% t8 L# O        
5 a7 Q/ F/ A2 f3 I2 |0 P9 H    // Then we create a schedule that executes the
" z6 H+ c+ j. I; X- @' R1 B    // 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.
& o+ f7 z' B/ I- K; g" Y
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
- E: n+ u7 x8 D9 N- F# @    modelSchedule.at$createAction (0, modelActions);
        
& e5 I' a7 t# @) X    return this;
& f6 Z% ?4 N# f& B  }