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();
   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
) q% Y3 G$ w8 l$ a+ |    // 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
7 l7 j+ X, U% S/ c+ w2 }; Y    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
2 I$ ?+ x& @, ^5 Y4 q+ v# C, }    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
* N7 H+ a9 X' f+ ?3 V    // `randomizeHeatbugUpdateOrder' Boolean flag we can
; P8 A, S  f/ E    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
/ A; R  h. M  t& `( }9 X! }    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
, w# y( r) e( i: e  J        
    // 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
$ ?: e' ]/ g4 z6 T    // indirectly by some other process).
3 v, c8 ^" D. L# P4 l+ W/ f   
    modelActions = new ActionGroupImpl (getZone ());

) t( i7 V9 l; G* k+ L  `; g( P& v% \    try {
( R7 \4 O/ Q0 P/ L/ D3 F      modelActions.createActionTo$message
- |; m1 r, k# v6 b        (heat, new Selector (heat.getClass (), "stepRule", false));
# W3 m  z$ G7 o/ [/ e    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
0 y. F8 h  e2 i      actionForEach =
: }8 k- F8 B" i) @, c        modelActions.createFActionForEachHomogeneous$call
' |1 j  e3 y: i        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
% d5 V9 L1 M7 u/ x8 c2 E      e.printStackTrace (System.err);
    }
) X9 ^" b0 B* {; W* t   
3 q! z# ~% y& H; }4 w    syncUpdateOrder ();
$ }6 i' a  m9 ^  r5 u
    try {
: C  u; o- Q+ u' y/ f3 Z& M6 Z# a5 o      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
2 S- r6 R5 I# W* H: k& N% g/ F    } catch (Exception e) {
' ?/ G: q* b+ _0 c      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
" y4 H4 L9 Z4 t2 C, k) r. w    // modelActions. modelActions is an ActionGroup, by itself it
- J  E; D( q  I6 I' f1 e: K    // has no notion of time. In order to have it executed in
  D' e6 O, ^4 F9 [1 H    // time, we create a Schedule that says to use the
2 k, X. @( {) o; [! y    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
% d2 K8 x4 j* U% Y1 m* a# a, D    // time step.  The action is executed at time 0 relative to
; {! B3 r/ I: I" e: I# O- G. w7 K    // the beginning of the loop.

: {, n; m8 R& t    // 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);
) ?. K3 L4 C# A4 Y' d! M) F  }4 f        
1 j. h( }4 o' @6 Q; |; a    return this;
  }