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 () {
- }8 y$ `) ^: c8 W' @    super.buildActions();
0 M2 C1 X0 I7 E1 k; d   
! c  |( P- _" D) ?, z    // 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
5 _1 Z- c" c3 I% v  w    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
5 L/ k& K  K  z4 J+ X        
    // Note we update the heatspace in two phases: first run
. o! v1 o( I. m* I" f6 W/ q1 h) w7 C$ J    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
  C- ?, ~% M. c. x    // significant!
        
    // Note also, that with the additional
" `# u) @  {% F& p- R# T    // `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 Z7 @- S4 c: j; M    // list from timestep to timestep
3 e& G/ t0 c/ T& B/ J1 T9 }        
/ J! H) ]& P- `9 O" \9 E    // 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).
   
* S8 S6 p% Z, [    modelActions = new ActionGroupImpl (getZone ());

2 k3 w7 I! u0 q* e4 _    try {
      modelActions.createActionTo$message
) t. L8 I' e; o+ x2 o        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
8 v$ K% h/ c' J# d# {. c" A      System.err.println ("Exception stepRule: " + e.getMessage ());
2 V) i, H7 z2 E- S, I    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
7 j0 D( u. t) Y6 x" \& X: S  E      Selector sel =
% O2 F- O7 z* p  e8 N        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
1 x$ u, f' B. T7 }: x4 [- @        (heatbugList,
         new FCallImpl (this, proto, sel,
; Q, }1 }- Q" j& a! r% t; @                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
- }$ e2 f! a, j* m$ s" P+ V    }
- \) P  K0 T0 N; D. u) i. n0 W& L; o   
    syncUpdateOrder ();
1 K0 `7 Z2 y, r7 u' ?
/ k2 h% A( p0 ^2 N9 a    try {
$ u3 ~0 h$ ]8 d" R3 c7 G      modelActions.createActionTo$message
3 D' Y; J( T" @# D3 q8 c. l+ j        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
0 H. l( g0 `9 g      System.err.println("Exception updateLattice: " + e.getMessage ());
) M0 Z/ d9 m  }: _) o+ x# W0 V% X    }
& U* H! M, i0 t; F7 E        
: G  n% I+ S" {0 K1 Q& g- r3 `* T    // Then we create a schedule that executes the
  q0 A# F/ G5 L    // modelActions. modelActions is an ActionGroup, by itself it
8 [& q" C% B5 H3 K  H! V. Y    // has no notion of time. In order to have it executed in
    // 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
    // time step.  The action is executed at time 0 relative to
) O7 w; h* Q6 ^7 \( g: L# n    // the beginning of the loop.

4 J( x, z7 Q! Z- ^3 ]    // This is a simple schedule, with only one action that is
! H0 _1 n, S) V, W0 A    // just repeated every time. See jmousetrap for more
$ t. ?9 u9 O. t- D& Z1 c' W    // complicated schedules.
  
0 ]; T3 T7 Z1 r) x: j8 I    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }