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 () {
. ~  i& H8 {' B+ j) S( h    super.buildActions();
   
! f8 d; p/ k1 a% 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
* P* p1 S. ~3 ?0 \6 l  x1 ^& D  F    // 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.
        
8 D/ a% j' V& W2 y    // Note we update the heatspace in two phases: first run
* {* K! y, x* d9 r  D    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
3 X& F, z4 `. d3 W: n& W% x7 P        
: Q) e* t1 ^' q  ]4 Z' s8 e$ T$ r    // Note also, that with the additional
) n. e2 v& f' A  L7 k1 A7 t    // `randomizeHeatbugUpdateOrder' Boolean flag we can
& C* \, V8 N" u! ?' k% w    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
6 `! a3 T! U# n9 m0 g    // systematic bias in the iteration throught the heatbug
: e* M+ W4 e! S. {7 W0 c    // 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
    // indirectly by some other process).
8 }2 v0 j9 Q; O4 J+ k. q8 F! a+ n   
    modelActions = new ActionGroupImpl (getZone ());

  s; y* ?" z( C  e  a% b. s    try {
      modelActions.createActionTo$message
4 q3 p! P! t8 o8 w- _  O        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
2 a6 w+ ?6 e9 c: u( }- b. ^    }
3 D( C; y* u6 Q5 d  L( E5 r/ d/ }
    try {
) I  z4 f; }9 m$ {$ O$ k  I1 ~      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
+ _$ `" X3 m5 ^% `& x! v0 w8 A        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
" q" y* i; v: k. f& q( U  V9 W9 @    } catch (Exception e) {
! l* Z6 _* z5 w6 P7 ?0 S      e.printStackTrace (System.err);
1 l, Q! o' M3 v    }
   
    syncUpdateOrder ();
$ m8 j0 O+ c  N/ X# X8 R) J6 v( y
, [9 g' z4 t% b" _. `6 S( w    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
" @2 Z0 b$ g. l% I' Y    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
' X- s/ S( M* A9 A/ x        
    // Then we create a schedule that executes the
5 D9 O4 p, c2 b9 {6 D8 H0 e- n  {    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
* c/ Z* D  v9 D+ U    // time, we create a Schedule that says to use the
$ H$ {, l- ]' o1 R    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
7 F5 B& f5 b/ C4 K+ u    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
2 z5 {3 o3 c; i( B( K; d
    // This is a simple schedule, with only one action that is
- B0 L3 f& z) h    // just repeated every time. See jmousetrap for more
- r, \1 w5 v4 r2 @* A( R2 G- d    // complicated schedules.
  
6 l) e* F. {) H, H    modelSchedule = new ScheduleImpl (getZone (), 1);
: J5 m6 l1 V7 K# x    modelSchedule.at$createAction (0, modelActions);
  v' p3 U  s) f5 r" `4 z8 j        
    return this;
- x9 w# {2 X, ?, g* y! Y8 d; w2 w  }