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：

public Object buildActions () {
8 |8 x9 Q2 n) U$ U8 H: }    super.buildActions();
. e) }  ?* B5 W' t& e* S   
    // 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
) h9 b- x7 ]$ P# @1 y    // 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.
, y* v; V: y; b6 i/ N3 z        
    // Note we update the heatspace in two phases: first run
2 q' ?5 G0 ]6 b. |2 q    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
) q9 ?( B! ^8 v5 k" T1 `6 o. o0 p    // significant!
5 d2 q. o6 d3 B2 O9 z        
    // Note also, that with the additional
* M6 J& b* ]. F* p$ Z    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
  G: }' G) R. n0 z' D    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
( [# m/ E8 ~7 @        
8 x3 S7 r, F1 H    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
. k  S$ G; `* v  j! s9 {/ ]9 _' e    // order of iteration through the `heatbugList' will be
% `  i7 @& i7 _" t. ?' k  Y    // identical (assuming the list order is not changed
8 w0 c: f+ K) d$ v& O( ]6 k    // indirectly by some other process).
   
& ^7 b5 \, b* v! q: i    modelActions = new ActionGroupImpl (getZone ());

4 o0 _8 Z3 D# j( D/ k    try {
      modelActions.createActionTo$message
8 t- r$ B( \6 A1 x: l4 w' W7 c        (heat, new Selector (heat.getClass (), "stepRule", false));
6 Q( }. @1 m& `7 B2 X    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

) `5 N% \# k2 e& a    try {
( D5 a4 V: I! Z/ B% Z4 M      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
4 l5 n$ q8 T3 u- t5 j        new Selector (proto.getClass (), "heatbugStep", false);
' R+ }! G5 p1 I      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
! Y' m9 \* [8 \+ v3 x2 o7 D0 j) {, ^         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
2 n, `! E1 \7 R& J  f      e.printStackTrace (System.err);
2 h1 P: t. Y6 a3 w    }
   
& b+ d% @1 [% M    syncUpdateOrder ();
! [6 V7 ~- n- j% v4 g! x3 A' }
8 D. H  Y8 J  h" I    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
0 F$ v  H3 z+ f' ~4 o6 K    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
6 M+ {! a$ X8 Q" M2 t    }
        
    // Then we create a schedule that executes the
3 j/ x; W1 i5 y6 z; ~" u    // modelActions. modelActions is an ActionGroup, by itself it
  X" i2 m$ g8 o: k: w    // has no notion of time. In order to have it executed in
$ |( g8 D, g+ t& l) l    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
! c, `6 \' h& h/ X# P    // schedule has a repeat interval of 1, it will loop every
/ S3 R: U8 [) z4 ?' c0 S; q    // time step.  The action is executed at time 0 relative to
# h# a! l( z" \4 e    // the beginning of the loop.

    // This is a simple schedule, with only one action that is
7 F6 Z* b+ b+ b    // just repeated every time. See jmousetrap for more
    // complicated schedules.
; _  b5 c5 X* c  e& P  
    modelSchedule = new ScheduleImpl (getZone (), 1);
; b8 b: s* O7 L* g: a3 e, \. ^    modelSchedule.at$createAction (0, modelActions);
        
) p2 h& ^! L5 [- T* I6 E    return this;
2 x" C) o: v5 x& `+ w; ]* O7 b8 D( C& s  }