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 () {
/ i) F5 U; U3 W* Y    super.buildActions();
   
    // 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 S+ i3 M- t8 V( v! V! p8 W; D0 F    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
3 u: }0 w. f7 ?; @8 p    // object, or ForEach object in a collection.
( S8 }" m" s2 `0 k3 E$ O        
) d5 v7 L0 o7 h$ l' x    // Note we update the heatspace in two phases: first run
; s# K' U: s0 X5 Q  E, x, x    // diffusion, then run "updateWorld" to actually enact the
  f- S" e  M. [% u    // changes the heatbugs have made. The ordering here is
    // significant!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
' n6 B+ u% ]( n- t    // 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
        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
5 I# e) f" h2 _% n    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
, d) G7 X/ j3 C2 X  S    // indirectly by some other process).
7 _9 q0 V) Z5 h6 K6 m: s' v   
    modelActions = new ActionGroupImpl (getZone ());
/ j  Z- _& O- {
    try {
* }6 P: @2 [( i, D      modelActions.createActionTo$message
$ |2 L; u4 D3 i* k/ x- v        (heat, new Selector (heat.getClass (), "stepRule", false));
! J9 o. G! C2 A    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
4 g* A) M) g. \
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
2 K) G2 [/ f5 T; A! q/ ]        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
* c: b  m" u* ]$ C, l                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
* `1 B- x! c' p9 r3 d: Q+ w! o   
    syncUpdateOrder ();

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
" l% f1 S' P# I4 ]7 l    } catch (Exception e) {
, |& d6 f- ^1 f! ~      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
( S: n% |& M  K7 C# g    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
9 j  M# K$ \/ L: y4 Q    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
! @3 ~' m$ L# R& i7 t& {3 F$ y* f    // time step.  The action is executed at time 0 relative to
9 E4 D3 a- `1 k, y) m3 d    // the beginning of the loop.

5 s6 H, Z2 h1 @    // This is a simple schedule, with only one action that is
3 f. H" t1 s% `( L' j+ Q( |    // just repeated every time. See jmousetrap for more
    // complicated schedules.
! ^/ }9 w& U- |" z5 o  
    modelSchedule = new ScheduleImpl (getZone (), 1);
- x  `4 F" |0 w4 F    modelSchedule.at$createAction (0, modelActions);
        
8 o! `8 X3 s* _7 S    return this;
  }