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：
1 ^; C$ J, f4 J0 A# [: S7 i, a6 `
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
    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
8 {" I/ l1 ~! ^  y7 |4 u# S    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
1 _8 ~' O  K6 ~        
! Z3 I3 N" s1 `6 o5 M# V    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
7 w2 n- S* P& U# h7 g/ C    // changes the heatbugs have made. The ordering here is
* {8 _! ^+ |$ B/ U- @    // 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
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
- f+ O" f; j6 Q3 H    // 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
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
6 `5 d) t6 Q$ K  _7 ]; [0 p
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
0 s8 ~# P" _5 Z$ @9 Y% \      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
* o4 I6 X) d. b. Z- w" S) {      actionForEach =
# }. y7 Q' T5 I/ Z6 b" `, n4 \4 ^! c5 ^        modelActions.createFActionForEachHomogeneous$call
: q$ ?; L" k$ c7 }% G# |- S        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
% {% J( P# l0 i      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();

6 P0 t' J1 K  S# G* V    try {
0 B( u" k# S8 t1 ~8 w3 m8 n      modelActions.createActionTo$message
( K, ^! O, L- [9 z$ B7 J" X5 n. |        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
  O6 g' \( [- u) m8 J    // Then we create a schedule that executes the
8 M" O' y3 V  L3 ]    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
) K! Q1 ^# e5 I% Y. m% k    // modelActions ActionGroup at particular times.  This
" T7 S  }5 }) ?! h, F    // schedule has a repeat interval of 1, it will loop every
- Y% r# [) Y3 r+ [; [    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
" q: [* F5 R( |* _
0 |" W/ x4 Y* `/ w    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
  
7 W2 k5 r  Y' f2 y8 `9 z( J    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
6 n) K+ m( [6 f: }        
. r' f9 P9 d! f9 `. F9 U7 }$ N, v    return this;
# _! w# u$ {3 Y8 u2 \/ ~  }