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：

& Z* j+ F& Z" K public Object buildActions () {
    super.buildActions();
   
& p4 _+ |$ q4 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
0 M2 s+ J% F+ z2 @    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
* N, f$ H$ J5 {4 S. ]    // object, or ForEach object in a collection.
. u" L& u. q3 a/ L! S# m        
3 }/ F1 U# J% E: B) g7 z1 M+ l/ P0 A    // 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
+ K$ t. u/ b* z8 b1 q4 j    // significant!
        
    // Note also, that with the additional
    // `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
1 |4 s- p/ p6 R1 O    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
' Y, j. E/ Y% o( e    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
; o+ h* X$ B6 U* o9 ?6 W   
    modelActions = new ActionGroupImpl (getZone ());
  @( S: g  F! o/ o8 e1 j
    try {
. G) K# v$ e; C" `, ]! K' s      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
5 |4 K5 w9 k3 `      System.err.println ("Exception stepRule: " + e.getMessage ());
3 n1 k/ N1 A. T3 K, `! U    }
3 T; H- x; H2 |% l. U$ G
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
) D; ^# A  g6 A4 K8 `6 ~8 f      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
0 y. j, K& ]# @0 k  u# h1 M: S0 {        (heatbugList,
( C2 x' s8 z2 _; E         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
2 R3 g! m% C! k$ H% j7 ]6 a2 I      e.printStackTrace (System.err);
, a& a8 l9 w6 S7 v. B( e    }
   
; G5 H; M' u- V4 {  ^    syncUpdateOrder ();
& e$ J! ^" I( o: C
3 _" @" ]' W/ [% o    try {
: Q) m& Y/ [- y- d      modelActions.createActionTo$message
( G* ]$ O# L2 q0 R1 P5 A        (heat, new Selector (heat.getClass (), "updateLattice", false));
8 N/ H( f" {3 h- e3 ~/ p    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
0 t- r" X6 ]$ r    }
$ Y2 \3 t8 }6 n& I+ y2 o        
    // 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
# b# b: c+ @" d1 C' p5 h    // 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
    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

+ R3 Y% f. u3 l1 z    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
3 I6 @/ O6 T3 l$ z; q- j5 {/ G    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
8 c5 o- [1 `! u% V1 O    return this;
  }