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 () {
    super.buildActions();
5 K. l- @9 r+ t9 j7 {   
; v3 w" Y; d: g' e, Y: G, U2 ?6 H    // 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
5 m3 H5 @0 K/ ~1 V! e$ w    // take no (simulated) time. The M(foo) means "The message
    // called <foo>". You can send a message To a particular
- R5 W. C) c3 d' E    // object, or ForEach object in a collection.
8 z3 y3 ^! Q) }- Z        
    // Note we update the heatspace in two phases: first run
8 x* i3 C! @7 \3 r' _2 ?7 ~3 E& t    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
    // significant!
* Q: p, a" c" {7 a, n. B6 o4 [5 b" N        
0 {2 A4 `; P- I! @" x. c: x8 @    // Note also, that with the additional
    // `randomizeHeatbugUpdateOrder' Boolean flag we can
' F) [+ r" @! t3 y- y    // randomize the order in which the bugs actually run
3 k+ W9 Y3 T# m2 L1 ~" R    // 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
3 h" G% P' Z3 _- M" H! Q+ Y! \    // a default order of `Sequential', which means that the
! n% _& r( v8 _& Z& f    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
9 |3 j' E# d& W8 g" T( b$ R    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

/ h0 l( a& _- c1 {' m* h' \    try {
% m; t; Z( I  d' h( m9 ^0 `      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
0 I. [; t) m" U* Z    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
    }
' n% y1 w/ v9 R* e& i
    try {
! {6 n; X# B4 }8 V      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
7 E" h) Z% X: C2 T- Z9 ^! J        new Selector (proto.getClass (), "heatbugStep", false);
8 H' Q1 K/ p# v- B      actionForEach =
) p: {) T: ]9 p  z! l; a        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
      e.printStackTrace (System.err);
    }
& W& ?+ N& K- s& p   
    syncUpdateOrder ();
' l' _) A5 k( Z; R7 _
    try {
      modelActions.createActionTo$message
$ {) V- _; a+ ]- L$ }        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
9 e8 V+ a6 o0 e" M& k    }
3 R' a  r" _% P% Q8 ^        
. q. o- A9 G( e    // 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
1 \: z$ s+ D; L0 |+ ]  Z0 H0 [- W    // time step.  The action is executed at time 0 relative to
5 x% o8 d4 x) ^( O. `    // the beginning of the loop.
- w7 I' ~; _8 r
    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
% D" @7 Q2 F* g    // complicated schedules.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
  }