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 () {
: h  C4 F7 r+ ^. N    super.buildActions();
9 z  n) h! Z" r) h/ d$ @. h   
% t5 s3 q5 ]4 Y2 m    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
- y2 h6 k$ L6 H# y1 ?; \    // executed in a specific order, but these steps should
6 C2 |# ?$ |2 ~5 q1 u" }# G6 C" k    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
) f# |3 O* Q! W$ ^4 [7 O. {" d    // 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 B' c% q    // significant!
6 F3 G) l' x; @7 I' G/ Q        
4 V) o4 o4 u- M4 E2 E0 J    // Note also, that with the additional
2 k# q- x: F+ T8 ?    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
/ m" Q7 j. G- ]2 q4 w( j    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
) v% h  s# I! i: E7 j        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
$ O4 l! H  o. D- N    // order of iteration through the `heatbugList' will be
6 a8 k+ h* B1 O, u) ~    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

    try {
      modelActions.createActionTo$message
+ t0 f9 T$ y$ u+ ]        (heat, new Selector (heat.getClass (), "stepRule", false));
% k0 h( s7 g7 D& y  h    } catch (Exception e) {
. U9 i4 Y% Z0 ]2 }8 R      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
& v; t5 `. ^4 r3 A" w      Selector sel =
" v% I( u6 ~' G7 |) P6 {2 m" J  }        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
/ w9 e( D/ Y) `- a6 y        (heatbugList,
& X  w1 O- G' L) K7 j         new FCallImpl (this, proto, sel,
5 }; s5 Q, J1 t3 x, A! Y( B. _! Q( T                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
0 v& w3 S$ G) E- ~/ W1 ^    }
   
    syncUpdateOrder ();

) l. C3 F- D2 D* z7 d5 A4 s    try {
8 e) `/ n8 {7 I7 z3 |) s! k9 W* H0 W      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
3 i/ V! F3 l/ P      System.err.println("Exception updateLattice: " + e.getMessage ());
# a1 E- A. B2 H  x( e. o    }
        
4 g% ?: F$ Z5 S& A7 Q    // 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
. ~+ C! P* P! {5 a& ]4 C5 t; ]    // 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
8 e9 z" e) \% ~    // the beginning of the loop.
$ K/ \1 G4 f. m5 h9 y! o
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
4 d5 e) ~, q" p/ ?! J    // complicated schedules.
  
& W- l' B! z+ q6 L! j( q# U4 H  |5 U" P    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
$ P5 \! ]5 s+ w  }