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：

5 l- w/ x. F$ S! u' a public Object buildActions () {
) M1 X. n! Y  W  p. ?    super.buildActions();
   
. r8 m- J# f7 @/ M/ X9 B' a    // Create the list of simulation actions. We put these in
8 s8 e* _0 p& i) ^+ T; T2 k    // an action group, because we want these actions to be
3 U) ?( e5 u, }$ Y    // executed in a specific order, but these steps should
2 v% `$ n8 Q$ H% m/ ~    // take no (simulated) time. The M(foo) means "The message
1 p) [. i( h4 ^# O. x    // called <foo>". You can send a message To a particular
, a" J3 K# V+ d  j9 F1 ]1 v    // object, or ForEach object in a collection.
        
5 l) |  [% c  A" `    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
2 ?9 s+ g3 _5 ]; [4 x+ w1 J    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
; {$ z3 c6 F& {& X. B, Q# M6 `1 H5 L    // 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
. o. A; t5 V9 ^# }    // list from timestep to timestep
2 Q8 t+ L/ i9 h" A, R: @+ N        
    // By default, all `createActionForEach' modelActions have
. z, c5 ^" C9 v0 x    // 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).
   
8 b) k0 M: `% }  t2 @: Z/ s    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
7 M8 Q, {8 |0 P; x' h# Y+ O1 S      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

/ w7 U* o. F! u) x- e1 u    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
. c+ f' S6 ^- I7 ?      actionForEach =
) x$ K+ L. g& u: r2 t: G        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
. t# Q) L6 x0 h) R. G# k0 n! T         new FCallImpl (this, proto, sel,
/ A; Z  ^% b1 H1 }& W                        new FArgumentsImpl (this, sel)));
* M; w) z3 X" {1 A7 S    } catch (Exception e) {
9 D6 n0 w& Z( p9 r% \2 I      e.printStackTrace (System.err);
' l9 a6 U' F1 R    }
   
    syncUpdateOrder ();
. V2 Y8 \- Y' B* F; M" ]: ]
    try {
( v1 V8 p, j) E# a1 x      modelActions.createActionTo$message
# B! _+ K4 r, `! H% x( X        (heat, new Selector (heat.getClass (), "updateLattice", false));
) F+ a  S' k% g9 H8 O5 l- Q- i    } catch (Exception e) {
$ t5 X3 c5 M+ q% U1 I      System.err.println("Exception updateLattice: " + e.getMessage ());
9 ^5 H2 o3 D# z# r    }
, i" [8 w& `# y; C& W, y9 g: B, s        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
- Y+ {" p0 j: S& R- K# p    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
) L/ z) Q6 E4 K5 c' ~  F    // modelActions ActionGroup at particular times.  This
9 r: N7 q6 c- r' `8 k    // schedule has a repeat interval of 1, it will loop every
( g# D/ ]- {7 S* ?    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
" z/ d. x* w6 ]: k
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
( e/ {: {7 I5 I  c! f) R  
( w$ i& o( ^- e/ L% |6 Z; }0 s    modelSchedule = new ScheduleImpl (getZone (), 1);
3 _: I0 H! M$ g) F! Z    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  Y& I' e- W0 X* |9 a8 R6 |  R  }