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();
* D2 L1 X0 x, S- C   
    // Create the list of simulation actions. We put these in
: I/ g1 Y+ m% f; G) T    // an action group, because we want these actions to be
$ O* X/ O- j2 K- j    // executed in a specific order, but these steps should
/ G- l' N; d! H* Y8 T1 |5 B, }) H    // take no (simulated) time. The M(foo) means "The message
1 O$ r8 O; f8 j! s5 v. W5 ^    // called <foo>". You can send a message To a particular
1 z+ C7 L, q! b; W# y- Z    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
( s9 q0 N; P2 V( y    // changes the heatbugs have made. The ordering here is
    // significant!
. t' c7 ]6 _. y" O+ L0 O        
7 G! U; E+ v2 w* k3 L    // 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
: j5 @2 s+ v! b    // list from timestep to timestep
5 J' W+ S) \- h: g3 {2 S        
6 U+ s* K4 y& L. p  V    // 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
1 Z: I& Z, a. S+ p, Z! l# Z    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

) M! o' I& b! n9 l) W    try {
( ~; G: U; R$ M$ K) E      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
( h) ?1 F0 i$ r, @' R! e      System.err.println ("Exception stepRule: " + e.getMessage ());
8 r6 [" C3 C8 q! |. d. A: l; _8 [    }

( B' u0 K6 r8 a  s! @3 A    try {
0 c2 v, v" e% F! x. e1 Z      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
' p1 Y9 O: z" E2 R* r. D- A' Y* F# r        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
+ z* v) H* H* g' ~                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
9 D/ n- v  a+ n/ x8 l      e.printStackTrace (System.err);
) i' G3 J9 K1 F" {( O$ L. V; J+ u    }
   
    syncUpdateOrder ();

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
* k+ _6 \' C! }" ?$ m8 i. w4 m4 b        
    // Then we create a schedule that executes the
1 n: M1 W) {4 r# g! g+ P8 r    // modelActions. modelActions is an ActionGroup, by itself it
6 N. z, O# h0 Z* W    // has no notion of time. In order to have it executed in
3 ^# g8 R: V# n. W: i: D) t$ }    // time, we create a Schedule that says to use the
) d' m  V' \1 I! O0 `, ]6 ?! s    // 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
2 `2 H5 h$ o1 B4 p. j: e4 @    // the beginning of the loop.
4 Y. `" b' \: G( s
. B2 z6 Z% d  {6 w, }1 G' z    // This is a simple schedule, with only one action that is
8 A: a6 s/ d3 z) o  J) h( [/ h    // just repeated every time. See jmousetrap for more
1 y+ U4 f+ p% e" U9 L1 R# a3 b    // complicated schedules.
, L1 H2 ^5 D7 L+ }  |. O# o  
2 H: I' I: f+ _7 i    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
% m5 D5 @2 l& L2 g8 G2 g# W        
    return this;
9 X+ E: E3 w0 p* K0 U/ j  }