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：

  F4 j) N6 z* E8 p% ~' R4 N9 Q public Object buildActions () {
" i" K/ R* O1 s$ {$ R    super.buildActions();
   
) Q( Z- @3 o& x6 ^0 Y* o# b    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
) }+ {9 ?" d9 n, S' _8 }" {# t( P    // executed in a specific order, but these steps should
8 m' P0 k8 b* G' A    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
. p: ^( ~: C) L% b, d    // object, or ForEach object in a collection.
/ W( F  n- r! M' Q/ K% l        
    // Note we update the heatspace in two phases: first run
    // diffusion, then run "updateWorld" to actually enact the
4 l& |3 ]. d8 ]+ H    // changes the heatbugs have made. The ordering here is
7 G" E9 J9 B1 U7 }. [  X$ \  Z    // significant!
        
    // Note also, that with the additional
9 M) G2 G/ `3 f    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
7 G9 f+ M8 y. X5 M4 {$ _5 R    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
+ R  \. _' c' M7 G    // 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).
- ^+ u! A* W; E/ Z' D; D   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
5 C; t5 a7 J4 \/ |! N! h      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
; C4 ]2 S; b: P8 H9 A% T8 z      Heatbug proto = (Heatbug) heatbugList.get (0);
" Q! O0 h  [( F" a. `      Selector sel =
' X, k9 g# P7 \2 }# G5 p        new Selector (proto.getClass (), "heatbugStep", false);
) q0 u% |( |; U% o. P! Y      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
7 j4 F# f1 ?) |         new FCallImpl (this, proto, sel,
3 U* ^8 i  k- z9 E9 |6 l                        new FArgumentsImpl (this, sel)));
, n; _) _9 s" J+ O$ }+ t- ]7 o$ G1 v    } catch (Exception e) {
      e.printStackTrace (System.err);
, N! R* G8 Q- C- q    }
   
0 Q4 [0 T6 P0 Y/ U. I! s    syncUpdateOrder ();

5 p- \* P$ j1 _  c4 C' {6 K6 Q    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
' G% }! x: n2 M2 I% S# {5 @      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
  n# Q9 d, d' C; w3 S/ M( K3 ]9 o        
    // Then we create a schedule that executes the
    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
9 p6 F) T0 }& S, r; Y    // time step.  The action is executed at time 0 relative to
7 B: S9 }+ p! H    // the beginning of the loop.
  M& s* s1 A9 y
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
+ Q/ ?9 P: a1 N* a! b( z3 |  
    modelSchedule = new ScheduleImpl (getZone (), 1);
) Q& x: N: k) e5 n1 @    modelSchedule.at$createAction (0, modelActions);
        
' Y. F8 F7 Z" o: j6 N" Z    return this;
  }