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：

: q# ?( M. b0 j% n public Object buildActions () {
    super.buildActions();
   
    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
    // executed in a specific order, but these steps should
    // take no (simulated) time. The M(foo) means "The message
# Z& l' p* v9 c: q    // called <foo>". You can send a message To a particular
  r; [6 k  i) r    // 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
    // significant!
- v( s3 u: Z' t& t        
    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
% p1 X! s/ J) A, _% `    // randomize the order in which the bugs actually run
8 [: f$ x4 P  ~: f+ z! A    // their step rule.  This has the effect of removing any
    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
        
    // By default, all `createActionForEach' modelActions have
5 R1 g6 w" k0 W0 v9 d    // 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).
   
    modelActions = new ActionGroupImpl (getZone ());

3 q, }* D" w' Z    try {
" A& Y; w- s6 {- w      modelActions.createActionTo$message
3 N( i( I8 |# o* H) z) Y        (heat, new Selector (heat.getClass (), "stepRule", false));
! Y- M6 \6 s4 N0 t4 G0 u    } catch (Exception e) {
+ J  u5 p4 m: H# w" v4 x8 @      System.err.println ("Exception stepRule: " + e.getMessage ());
/ M! ?( y0 _% ?    }
) _, L1 F; @8 d1 v1 s, o
    try {
) b! i* P9 N% x0 Q8 w8 e8 E      Heatbug proto = (Heatbug) heatbugList.get (0);
2 @: t/ v2 }' P# m7 P9 H7 Q2 ]5 G      Selector sel =
( }0 ?3 U" W" {! }) a% e6 J        new Selector (proto.getClass (), "heatbugStep", false);
; l1 A, [! \8 C/ }      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
% O1 s. l* W, d# T( ]" j  f3 v        (heatbugList,
  X3 T- ^" z  w+ p3 m         new FCallImpl (this, proto, sel,
$ n$ u/ k# b- G                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
   
    syncUpdateOrder ();

* {' p0 c! d& n, h    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
' Q" b* e* e& a6 D; w7 E) J# B, Q      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
6 c# ~. d7 ?5 @% V+ N' f' B9 @4 r1 L    // Then we create a schedule that executes the
  X7 p$ n6 B3 _    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
. Y% d# E9 M9 ~9 E1 l% f    // 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
) c3 V/ S4 P7 T! e. K    // 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
3 v8 F$ F% w" ]8 ?$ [$ \    // complicated schedules.
6 L0 ]% w& ]% G) M3 f8 o) y. N  
1 R* Q3 ^. _, o2 [8 V1 z  l4 w    modelSchedule = new ScheduleImpl (getZone (), 1);
: X" _+ {  q$ f" H& D% ?5 N) s    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }