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 () {
    super.buildActions();
, ~( M, c2 ^4 y! K7 P* n   
4 `+ F, h1 R: Q- f5 a$ p# W2 x    // 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
    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
- Z: f7 O! p/ K- Z    // object, or ForEach object in a collection.
        
$ I! L0 i  u) K4 a' g0 e$ e    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
, \3 u9 u8 y+ {- S; `  }    // changes the heatbugs have made. The ordering here is
    // significant!
9 p7 K/ Y* W2 r. u$ H+ a9 M        
    // Note also, that with the additional
- A) R( q4 e) G    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // 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
    // list from timestep to timestep
+ d  [; @8 O0 R( M6 y/ K$ w: s3 d        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
; E1 Z, n: D, }& O4 c, l    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());
9 h3 h% A, f9 U
    try {
      modelActions.createActionTo$message
2 G5 ?, h% @1 Y; C" d        (heat, new Selector (heat.getClass (), "stepRule", false));
. Z- [) i& C# i7 H9 g4 G7 d7 B% }% O: A    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
+ }7 @1 F  @* |. H$ i7 m    }
# @8 z& c5 J( ^9 u' d
& |3 }" `: P" s8 h' x    try {
' v* W1 ]3 ~/ V' u      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
8 X/ z. K4 C* C0 L& _; B9 c# }1 ^6 p      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
  G* b+ u0 U2 S! J9 s5 ]                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
# `) {. _; G# _5 c3 @   
    syncUpdateOrder ();
& H2 y$ C% w  l1 K6 J( h
, |4 w. d3 R! W! l    try {
- A" A" @; U4 U$ W; Z4 Y      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
& P( T. K3 C. x4 N4 ?    } catch (Exception e) {
. `' b) D1 ~/ y5 k      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
; K$ I) c) S2 V0 \    // Then we create a schedule that executes the
    // 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
5 r6 R" q/ v9 Y2 N1 k    // time step.  The action is executed at time 0 relative to
) [" B0 a, z8 `9 b; K    // the beginning of the loop.
: {% n1 A, V% g; [( d
' H& h, m0 d# I- \! O    // This is a simple schedule, with only one action that is
0 I( K4 D0 z* q; e1 A/ Y9 M% D    // just repeated every time. See jmousetrap for more
( }: `6 F+ P$ p4 g    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
& g  c' K" [: H  E  i6 _    return this;
  }