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 () {
& ]* ^: @' y9 A7 W+ O% c    super.buildActions();
   
. N' g$ C" j$ d: E; O' m    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
$ v' \9 I* A. q* h6 D3 o    // executed in a specific order, but these steps should
' E: d: s1 K0 @, S    // 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.
        
/ \2 n) D" g' D0 B2 j: {) E    // 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!
        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
+ f6 X' L- F0 i' R5 [. Y    // randomize the order in which the bugs actually run
- d; \5 Q5 o& F( ]2 C0 B5 r( V' r9 I0 l    // their step rule.  This has the effect of removing any
! h+ B7 ~+ D2 X    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
2 d* H* T# P+ w2 }  `    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
# l3 R6 P, m  U& ^0 o3 _$ t+ W# t* I    // order of iteration through the `heatbugList' will be
- c: p4 a0 J, w+ c# _    // identical (assuming the list order is not changed
    // indirectly by some other process).
# s9 R3 A' t! K( ]- s$ D3 `   
7 M5 l4 ~2 w! n5 _9 P    modelActions = new ActionGroupImpl (getZone ());
, J9 @, n$ q' T  B' Z6 L
    try {
      modelActions.createActionTo$message
" |1 c+ i& }+ j9 Y        (heat, new Selector (heat.getClass (), "stepRule", false));
3 a0 s' k- D# O; D1 l- B) D    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
' S; `+ ], }5 s  B* |    }
* `4 Y/ \1 ~8 `8 U) V* ]- }
! U' ^/ g2 ^; l0 j" h! r    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
8 c6 _! H  x+ x5 h$ O7 b; d$ w         new FCallImpl (this, proto, sel,
- a  f, _: x2 c+ U7 y, }" Z                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
! w. _5 R* l) j      e.printStackTrace (System.err);
    }
   
' @6 }5 {3 L9 H. F. l' ?+ ]1 i/ `    syncUpdateOrder ();

    try {
% R, h* B2 ^+ H: `* P% K      modelActions.createActionTo$message
4 _8 N" p( m( D        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
. \9 G1 y4 O9 p; G3 ]9 P5 T. [% T        
8 D) Q2 R2 z9 Z: Z+ t# l    // Then we create a schedule that executes the
7 ~" r) \, E6 D% z$ k* Y    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
$ g5 G) S5 f* h6 o1 Q    // time, we create a Schedule that says to use the
4 N5 E8 y/ N0 u4 g    // 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
    // the beginning of the loop.

    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
% M( v  W+ V  V+ Q' }    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
$ t  E# ~) P0 b" j) |* f  {% M- X  A        
. j. w& t; Z' _& K/ @4 F    return this;
9 G# h2 s: w& Z0 C! g; v# ~$ x& J# B  }