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 () {
- U  T) J# u1 G, G  k    super.buildActions();
   
    // Create the list of simulation actions. We put these in
! I, g" X% E! T& }2 b" Z3 g! {    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
1 M! z  @+ P: k, T- Y9 r1 l    // 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.
        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
) P& W, A* G( ?        
6 }8 t' T, Y, n" g9 B8 T    // Note also, that with the additional
* K$ }  V/ D# L- O) L    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
9 x4 {& p: U. U/ a2 E/ G    // systematic bias in the iteration throught the heatbug
& W! \2 Y1 h; D    // list from timestep to timestep
        
& p* f  F* x0 X" g. _- M    // 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
. {9 W- U& r) X2 D  g0 e    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

9 L! ?5 {' \  a    try {
- _2 J. c8 w1 r      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
, a. i! c& ?: t; m; T! E' G* o" d      System.err.println ("Exception stepRule: " + e.getMessage ());
, J& c8 i, d: \2 W' @1 u- O. Z. S5 T    }
% k- x( y5 a8 B! I7 ~# [2 Y
    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
) b. Q. g+ J: E7 H+ {. _& S      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
0 a: G# l( v) W9 Z' o9 m1 ?      actionForEach =
- m4 e% q* r  D5 B        modelActions.createFActionForEachHomogeneous$call
$ p% }2 B& W  n( r( j        (heatbugList,
" R) F2 F1 A1 l# Z. G         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
# R9 K! H9 X/ k9 v1 ?, e: f7 `    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
0 p. o: y* [( F2 P; T: P/ m: B    syncUpdateOrder ();
4 I; ^$ b2 M% O/ y0 x
    try {
      modelActions.createActionTo$message
9 @; J5 g( c& |9 p: J        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
; ~$ o' B1 Y9 z3 V. ^! r8 v" p      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
5 O' V8 X- l5 v( {. N1 e7 ?        
' z3 o# m8 H1 N+ r    // Then we create a schedule that executes the
) o4 `6 P: `- C- A    // 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
5 V7 _+ d1 ^; p" k    // modelActions ActionGroup at particular times.  This
: }  r% _" N% T) M. h    // schedule has a repeat interval of 1, it will loop every
    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
7 v/ |+ n4 }- S9 X
, b8 Y. ], q, K& L) k    // This is a simple schedule, with only one action that is
- l& D$ v) x5 a5 a    // just repeated every time. See jmousetrap for more
( [' E" w, u6 d, b! K    // complicated schedules.
" G; h3 B' R' D1 b3 J4 }  
    modelSchedule = new ScheduleImpl (getZone (), 1);
  P# H% T. K8 t6 ?& e- ^/ ~    modelSchedule.at$createAction (0, modelActions);
( x" q/ a1 @" }( r        
4 o; x( P4 e: r( J    return this;
  }