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：
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2 ]5 e1 `' H+ i4 E/ S7 R public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
8 M% s2 `. U$ v8 J+ n    // an action group, because we want these actions to be
% L. a3 Z) t6 }  H) `1 ^6 J5 E    // executed in a specific order, but these steps should
7 B7 O' ]# N( L: q  }# X9 F    // take no (simulated) time. The M(foo) means "The message
4 W- a8 T; Q& x- ^8 |    // called <foo>". You can send a message To a particular
    // object, or ForEach object in a collection.
- ?+ F. T7 V) c  Y8 c' S% |6 v        
    // 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!
( Y; h3 X9 ^8 n7 ~: l% R$ }) D        
    // Note also, that with the additional
: ~7 C, a! d# {) K* @: `    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
7 _/ o+ a+ Y! Y; j( S! f" [0 W2 B    // their step rule.  This has the effect of removing any
# R* C9 W! u2 v  i; R; h    // systematic bias in the iteration throught the heatbug
3 L& h1 e9 [/ K9 d. n- o( ]8 y, C    // list from timestep to timestep
        
8 x+ X" A$ 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
2 W1 K6 G& E& r    // indirectly by some other process).
   
7 m& t) S- t5 e" n' h  |    modelActions = new ActionGroupImpl (getZone ());
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    try {
- j! I+ j, |% p+ {7 q0 Z4 D, Z# n1 g$ y      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
) h% h) s6 T' t; }    }
* Z2 w( M5 d( E. v( d# D5 \
( w. c* C$ {6 p) b  y' H    try {
3 L0 ]7 F6 E* s5 r, c: C      Heatbug proto = (Heatbug) heatbugList.get (0);
$ g* Q1 o% W) U6 ?& C      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
& n  M6 @% G1 t' P      actionForEach =
) ~% |7 E; }, Z1 Y4 B        modelActions.createFActionForEachHomogeneous$call
( C$ I; I0 }" I2 b. F        (heatbugList,
  ]7 [% @, R, g/ f4 U, h0 z) D& B         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
1 ]# c+ |6 T* q5 K    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
( Z5 P" W* R' o( U( F9 B2 W0 I5 C   
    syncUpdateOrder ();

    try {
6 N: x+ l9 m6 s6 y" t      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
1 O( I/ r$ l) ^- y$ }: D- a    }
7 E' `# e2 {) V0 L$ X        
    // 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
6 B3 T2 `! }, z; Q# C    // time step.  The action is executed at time 0 relative to
4 k! B6 ]- t/ _, t% u* f! |0 {    // the beginning of the loop.

' n, _+ ?# S4 `: d2 q- Y    // This is a simple schedule, with only one action that is
9 b& P  Y0 g5 b: w' M    // just repeated every time. See jmousetrap for more
4 d6 Y# y" |) A& i    // complicated schedules.
5 W2 H3 F" [; S4 k1 h  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
0 s+ l, y# j/ d6 n/ [) Z" A) R  }