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 () {
0 C3 k3 q0 f; e) T' q# V: F9 X3 e! X+ M    super.buildActions();
7 Q3 [# i8 n- Q' ]2 R, n   
2 q& K2 d! y/ J- `0 a4 W    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
+ M& Q9 s. S+ y% k( W4 e/ {6 b    // 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.
        
    // 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
1 p6 O! l5 X% ?9 m: R3 L    // significant!
        
    // Note also, that with the additional
" n' h1 O+ h, u! U3 g, V    // `randomizeHeatbugUpdateOrder' Boolean flag we can
7 k& c* G2 S# s3 c8 L- k$ {    // randomize the order in which the bugs actually run
, ]: X, ~; E* L    // their step rule.  This has the effect of removing any
# G/ n" U4 W" b1 `$ ?( q* ~) }6 P1 E    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
1 |7 T. ]3 D3 l2 u- j        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
/ u9 X9 i3 d0 V+ c! V    // identical (assuming the list order is not changed
    // indirectly by some other process).
- |" \, X% q- K, t   
    modelActions = new ActionGroupImpl (getZone ());
6 n8 v; r" J  ]* {7 R; k0 T# I
    try {
      modelActions.createActionTo$message
' D' p$ Y: e% t) |3 d        (heat, new Selector (heat.getClass (), "stepRule", false));
6 G3 T. f1 n1 Z% M3 Y    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
$ D3 i# V+ d4 _# x) {, _    }

; v* K" W! ]. N% I. k7 b6 ^) t    try {
0 j  k0 Y  c0 e  ~2 o      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
* z6 t" ~+ |2 ~' A- a        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
7 u$ [2 i. M7 M" f0 D; H0 g- q        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
+ S" k2 s: G/ G$ z; b    }
& P7 n) @! Q5 |% u7 J( [# {   
    syncUpdateOrder ();

' ^: ?0 e; q& U) ~, O    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
# g, N7 G4 X; s0 a, ?    } catch (Exception e) {
; U( ^7 K+ ~0 v9 k! [) ]      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
4 K: ?8 X4 c! ^/ d2 N- _7 M0 W: W        
5 A5 P0 N/ |) y    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
" C! a/ p! i" y( p9 g' U$ F; H% `    // 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
  }0 K: ]4 \3 t* H* T( p! L    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
2 X" Z  R: ?, \6 }  W
    // This is a simple schedule, with only one action that is
" o7 B9 k( `2 _, ?4 I: F5 ^    // just repeated every time. See jmousetrap for more
; `% A% N$ i. b4 i: {5 v/ z    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
" Z$ j& F; Y- G& Z8 b# w$ z& W$ e( C/ w    return this;
  }