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：

" {! A! L7 K& Q/ o- l0 |/ E' R. I( ~; i public Object buildActions () {
    super.buildActions();
3 P+ }% c" _8 y8 r  t, M/ K3 Q# {   
    // Create the list of simulation actions. We put these in
& n* ]$ ?1 \/ m/ P2 w8 _- X    // an action group, because we want these actions to be
/ B9 x& ^) l' r, p    // 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
( a; ?4 J( {; F6 J    // object, or ForEach object in a collection.
- z: J9 x) \6 _" c; q" R        
9 B4 {. w6 E- M2 N' u) e6 z7 h; b    // Note we update the heatspace in two phases: first run
' J3 T$ Q3 \" H# n; s. c    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
! S0 N  ?1 Q, w) _; r        
# j! L. o  Y2 Z    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
" c# ^0 ~7 e( K* Y    // systematic bias in the iteration throught the heatbug
( t" h' \/ J* H& u8 B5 g0 J8 L/ e5 s    // list from timestep to timestep
( v# u1 j9 ]" H* V" U$ m3 `$ M        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
. E" P2 x: I. q. `+ m* b! d" ?8 u, ]    // identical (assuming the list order is not changed
    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

: ?8 k6 x% Z. A, p9 A3 R    try {
8 \. }7 b' V- `4 e) v      modelActions.createActionTo$message
" Y; q) Q0 C; J& }0 i. z( m( J        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
1 i4 F4 h: M  E$ `      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
, P1 k1 x. m7 ]  H2 Q, l
! M& F( Z: ]1 @4 ^8 \6 M5 v$ V' z    try {
% n5 `0 n& N: _9 H! ^% H: {- E      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
) E1 @$ q2 I  _) p6 w, ?: G7 c        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
2 W- P" B1 e) k7 B  e        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
9 Y4 w% Q1 \0 |- H5 T8 P- \   
    syncUpdateOrder ();

% n. d. k  Q9 i' b" p; e    try {
      modelActions.createActionTo$message
+ {2 z, h8 J/ t, C$ @) Y        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
# a" ?( O, O0 U% b  a      System.err.println("Exception updateLattice: " + e.getMessage ());
, u& }! k! p5 v% U0 G9 |    }
        
' s9 P& _. ]& o# {/ [; h    // Then we create a schedule that executes the
  S7 j0 J) Y0 }; E- g& a( I, d    // modelActions. modelActions is an ActionGroup, by itself it
3 K' ?; ~( m5 G/ c3 B) @' d1 Y$ 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
2 w0 L; D$ z" c- D4 `- s    // schedule has a repeat interval of 1, it will loop every
& l$ S7 ^1 G$ u$ r- y& a! I    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.

    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
( R& c" ~8 j: |& S4 J  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
+ }* S0 {" G2 ]+ M# h9 X        
3 t: ^$ p6 h$ I" g  T) g# r    return this;
( l* K+ q+ ~, n  }