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();
) D: L% V4 o6 \9 s) K$ B   
. ~' }, f8 d! O) N) e/ Q2 y    // 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
    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
        
& B2 e& a3 ~4 @8 z    // Note we update the heatspace in two phases: first run
8 d8 c; p+ u; G1 v2 F" h    // diffusion, then run "updateWorld" to actually enact the
0 }* [( F" l, D    // changes the heatbugs have made. The ordering here is
7 E; _4 c7 X* u: i' L1 a, {    // 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
4 {5 ?; b( b! C" v8 ^+ l# E0 R/ D* m0 i    // list from timestep to timestep
        
2 O* \/ |0 _8 W. r9 O- Y    // 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
    // indirectly by some other process).
   
: I2 c& f0 z6 h    modelActions = new ActionGroupImpl (getZone ());

8 x5 Y) ^% j6 n7 Y    try {
      modelActions.createActionTo$message
+ S- E7 P* m1 A4 V/ j, H8 ^        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
; z/ ^5 k/ l' A# L$ i      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
5 W" o- C% `, r7 ]" c1 _+ }( E
! X* E+ e" m3 z  Y6 g0 e( m$ l    try {
7 Z  m# D7 t' D' ?% e. r      Heatbug proto = (Heatbug) heatbugList.get (0);
) W  |% _! Y) }2 k% N0 ]+ J      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
7 j. I# c' Y5 J1 p/ S' F      actionForEach =
7 ~2 n# Q( d2 B        modelActions.createFActionForEachHomogeneous$call
) D' s7 O  ?0 q1 O2 H$ g" m# `        (heatbugList,
1 T6 N. b0 C( r! D. F         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
+ M9 Z' k  A, b2 s% N    }
   
    syncUpdateOrder ();
* f/ I9 S$ G- z1 c& w( G3 f
8 M+ v+ |7 O7 L: r    try {
      modelActions.createActionTo$message
7 w9 _' t, n# W% N3 }4 [" ~        (heat, new Selector (heat.getClass (), "updateLattice", false));
1 R9 J1 T5 P9 ^; ?5 k8 V% W    } catch (Exception e) {
7 `  W7 {$ F, b$ L      System.err.println("Exception updateLattice: " + e.getMessage ());
9 l( T1 q" j! D" |7 a% d% T$ M    }
        
4 W8 c( T! D6 C    // Then we create a schedule that executes the
* a) Q  `. M3 |/ N    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
, J( x4 s' s4 R8 P* k* P    // 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
  X9 O9 p  d6 }- O, v2 w    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
6 Q9 D6 k- y- {( Y; h% B6 P
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
9 O3 D" K; F- Y7 h% _  
    modelSchedule = new ScheduleImpl (getZone (), 1);
2 |2 u1 l/ c2 p% w; t8 w3 b    modelSchedule.at$createAction (0, modelActions);
        
+ M6 d. @0 i) R0 d9 y# v0 T- E    return this;
  }