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 () {
$ O: N- x# F0 `    super.buildActions();
6 n! n; V% }: q   
, R# \- m+ I" z  G1 I( A# u    // Create the list of simulation actions. We put these in
    // an action group, because we want these actions to be
% t5 t8 ]3 h% p& |) D/ g+ z    // 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
    // object, or ForEach object in a collection.
. M; ^4 H* B4 ]! Q        
    // 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!
# q, V+ f' e4 g        
) n, F; D" m3 F    // Note also, that with the additional
1 G* P4 e: z4 `' C+ z    // `randomizeHeatbugUpdateOrder' Boolean flag we can
    // randomize the order in which the bugs actually run
    // their step rule.  This has the effect of removing any
* u0 U7 E( b& Y! o$ z4 I    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
) }/ i: R8 [! J5 M3 [        
+ I; ?" C' \7 l8 r    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
    // order of iteration through the `heatbugList' will be
6 O2 N, d3 P' V, E& S    // identical (assuming the list order is not changed
: V- V! ], Y" J6 G- m5 c; H    // indirectly by some other process).
   
    modelActions = new ActionGroupImpl (getZone ());

    try {
: o' a+ [( M9 a/ c2 `      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "stepRule", false));
( w, t7 [  _" q( S! ?0 }4 u    } catch (Exception e) {
) \$ H2 Q) \3 J8 D7 X( v/ g2 }      System.err.println ("Exception stepRule: " + e.getMessage ());
    }

    try {
( [4 Q3 r9 q2 q  Q# \      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
        new Selector (proto.getClass (), "heatbugStep", false);
      actionForEach =
& f0 _  f0 Z' w8 W+ x* S        modelActions.createFActionForEachHomogeneous$call
0 p8 G7 t5 G5 w$ `1 q; e  K1 r3 }        (heatbugList,
         new FCallImpl (this, proto, sel,
6 p5 F9 F" |2 A( A1 Q                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
6 }% s: f, l, y. H: p      e.printStackTrace (System.err);
0 c, f2 t; m# ?2 \: u    }
: K" c, M% y3 {8 f; ?3 q   
& a( w4 S  B: T/ g# i9 j# C    syncUpdateOrder ();

    try {
      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
) i/ S+ L  s' W2 A        
    // Then we create a schedule that executes the
/ C9 N0 _" q0 f/ \  z5 G. Y. x. ?+ u    // modelActions. modelActions is an ActionGroup, by itself it
    // has no notion of time. In order to have it executed in
( \7 R2 l! u% \$ P: r) `    // time, we create a Schedule that says to use the
    // modelActions ActionGroup at particular times.  This
8 d* U" z/ q# \) f: B    // schedule has a repeat interval of 1, it will loop every
8 D3 F6 Y, P* |    // time step.  The action is executed at time 0 relative to
    // the beginning of the loop.
/ _" D- H3 j  x& q+ q
6 m2 }5 u& F4 X" f7 [/ W    // This is a simple schedule, with only one action that is
    // just repeated every time. See jmousetrap for more
    // complicated schedules.
" X( C+ B' l; [" X0 v  
' o3 _  j) Z+ U    modelSchedule = new ScheduleImpl (getZone (), 1);
    modelSchedule.at$createAction (0, modelActions);
        
    return this;
: |& W- t+ o$ i) U8 z3 W( _3 z  i7 `  }