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：

( A: ~- t5 S% ]' a$ c& m/ h9 x; C public Object buildActions () {
+ J) F) }0 |4 A. y' m: R+ G    super.buildActions();
& Y1 s" ^- j6 e   
. v/ m; G$ `; X    // Create the list of simulation actions. We put these in
' J5 d8 i- C4 w0 M6 U6 E7 A: {, t/ E    // an action group, because we want these actions to be
, W% @3 u) p( G1 b/ k' M$ d/ x    // 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
    // object, or ForEach object in a collection.
& m7 ^3 q' y# D& q' W- _- G( e        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
) y* _" @# K+ q- O# n! h' A+ J    // changes the heatbugs have made. The ordering here is
    // significant!
8 X: Y2 j# q: ]6 {+ x        
( Y% B: m" B( L" U2 l: N' u& X    // Note also, that with the additional
7 e1 D; i4 t7 @5 s! l- ]    // `randomizeHeatbugUpdateOrder' Boolean flag we can
9 w9 g. S4 v( b5 R" t8 N# h2 N$ H    // 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
8 b. ^/ t% _. Y% _        
. x# j% U* e1 |& w- z5 K* B    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
, s( [3 c1 U9 B9 r. [    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
: x2 {) r( [$ l. Q5 v( _    modelActions = new ActionGroupImpl (getZone ());
! ]& I( R# ~, x* S' V6 U6 _
    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
2 y; M( e) s  d  t* `1 u) D. ?    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
" d. b& J" }4 G    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
5 L: O  g1 g- A      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
5 _4 M6 P. g% H* Q) H    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
' Z) u3 c4 t/ |4 j, f2 {   
    syncUpdateOrder ();

* P. e' m* s0 t    try {
3 Q; ]$ U/ Z# t2 [: {1 D% c      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
/ A2 Q# `" }0 C9 c- ]    // has no notion of time. In order to have it executed in
% @$ q  m" t- }    // 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
! z* H/ b" m2 z* t    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
, X% s& q( x/ F! ?
" q2 v- K2 f0 A' z    // This is a simple schedule, with only one action that is
1 q! b( w9 p: j4 x6 }* {    // just repeated every time. See jmousetrap for more
    // complicated schedules.
# o7 d3 `3 Z) \# m# ?! {5 ]! h% E" C  
) c3 v4 A5 v" s5 s    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
* U* h5 x) ?1 y' F    return this;
  }