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：

+ g6 n0 f/ N% A3 D& _2 B  | public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
; W+ V/ N  [8 w- U" f    // an action group, because we want these actions to be
: S! n1 }3 j$ I/ y    // executed in a specific order, but these steps should
! [8 M  }' e: n( s    // take no (simulated) time. The M(foo) means "The message
8 }$ q) N6 G- P# K+ n    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
6 d, n8 o# k' e5 @& q: {        
* U4 _7 r# p4 l    // 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
7 m' m; x% O3 H/ h* f' c& f9 t. F    // significant!
        
4 C8 P3 ?5 ^" p    // Note also, that with the additional
) X! u1 d. l. f8 @2 u3 c# M    // `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
$ s0 ~" l0 D+ z) D: B& M, t) [    // list from timestep to timestep
5 T+ q3 v% h+ R/ {# i9 z: n) d        
$ }: R; `8 T' d7 U    // By default, all `createActionForEach' modelActions have
6 }' z8 z3 j7 f6 s% E0 O    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
7 g+ e6 Z4 i* A6 t  \& H    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
0 v) B4 ^2 h* K7 l& o) V' A! E    modelActions = new ActionGroupImpl (getZone ());
& u; }& ^8 v7 `+ e3 Y2 i2 Z' H  g' C
    try {
3 X* k/ T4 c+ J% g2 g5 U      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
* ?6 @7 t7 S3 u# D) j      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
2 s6 n, B9 x0 ]/ q7 _; s      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
' W6 ?) |( E! H9 z" O  g0 X: |- b    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
6 t5 d% \! m: l. Z0 a% b2 ?   
    syncUpdateOrder ();

    try {
0 j5 f7 @' i& J* y8 d* Z0 V1 _; G" T& K      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
# q! Y% ?7 k: L    // 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
8 k8 U+ K9 |" q# T* d& `  j+ ?    // time, we create a Schedule that says to use the
9 G( l' w$ a+ g3 c! f3 c    // modelActions ActionGroup at particular times.  This
* L! H! H5 g# `9 T4 w0 ]    // 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.

    // 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);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
$ d9 {8 Y0 x$ i) {$ g  }