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：

7 G$ x$ c5 k5 ]; p0 G3 U. P9 h public Object buildActions () {
    super.buildActions();
& {$ p1 {* R$ L9 M3 j1 R   
/ R% t! c, n) b    // Create the list of simulation actions. We put these in
" q8 a# h& e# {, m$ w: m    // an action group, because we want these actions to be
/ N! A* _& U* V4 M) s6 E    // 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
4 K. M5 y2 O7 j' j- |+ t    // object, or ForEach object in a collection.
        
    // Note we update the heatspace in two phases: first run
! Z% S4 V$ ^7 k/ f5 `% m    // diffusion, then run "updateWorld" to actually enact the
    // changes the heatbugs have made. The ordering here is
9 z" R" |5 d' S5 }5 Z! m, W% C2 o    // significant!
2 M: u, A3 r1 o! I5 f        
- m9 @' _# {4 ?8 s$ J5 L4 I    // Note also, that with the additional
# L& R7 V# K! J    // `randomizeHeatbugUpdateOrder' Boolean flag we can
. p3 g  B5 K: `0 w& O' O" A    // randomize the order in which the bugs actually run
- z7 L/ B6 r7 V: i3 H    // their step rule.  This has the effect of removing any
  ^8 f6 h. Y7 y& v, z    // systematic bias in the iteration throught the heatbug
    // list from timestep to timestep
  t; `6 [  X$ \9 J8 l+ k        
    // By default, all `createActionForEach' modelActions have
    // a default order of `Sequential', which means that the
9 ^9 \% N8 b: R/ ^) W    // order of iteration through the `heatbugList' will be
    // identical (assuming the list order is not changed
    // indirectly by some other process).
; d3 @+ E& H) Z/ p- D* V. _" d   
    modelActions = new ActionGroupImpl (getZone ());

# k9 _/ Z  R  E    try {
      modelActions.createActionTo$message
5 o% n) A  S" g- R% i3 |        (heat, new Selector (heat.getClass (), "stepRule", false));
    } catch (Exception e) {
      System.err.println ("Exception stepRule: " + e.getMessage ());
) S7 p) G, c* E1 k4 |2 p( e7 T  L0 @    }
8 }5 E  A- [1 @' D/ {
0 b7 T$ T. e( {6 |, D( |7 t    try {
      Heatbug proto = (Heatbug) heatbugList.get (0);
      Selector sel =
0 {* t; g# o  ~" @        new Selector (proto.getClass (), "heatbugStep", false);
. l1 W  j$ M/ E# U. L      actionForEach =
        modelActions.createFActionForEachHomogeneous$call
        (heatbugList,
         new FCallImpl (this, proto, sel,
/ |9 e7 d3 Y- ?& j/ A- G" v& T                        new FArgumentsImpl (this, sel)));
    } catch (Exception e) {
, V0 X, D# I  ?5 e      e.printStackTrace (System.err);
    }
   
. f  D- T) w! Z1 H    syncUpdateOrder ();
/ A3 k# m% G+ W& Z5 P  c
3 r4 V+ ]: f5 ~0 S    try {
# l7 X7 u' Z" j% k      modelActions.createActionTo$message
        (heat, new Selector (heat.getClass (), "updateLattice", false));
    } catch (Exception e) {
% U7 `7 o9 m6 t6 N6 _. G      System.err.println("Exception updateLattice: " + e.getMessage ());
    }
        
    // Then we create a schedule that executes the
' _7 Z" l9 D8 A    // 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
$ F7 ?6 [) G" k5 w    // modelActions ActionGroup at particular times.  This
    // schedule has a repeat interval of 1, it will loop every
4 D$ D2 O3 y) s8 n9 k4 ~    // 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.
  
    modelSchedule = new ScheduleImpl (getZone (), 1);
. U- A% X$ _' X3 @0 N5 A! N" J    modelSchedule.at$createAction (0, modelActions);
        
7 `5 u) Q  p& h9 h    return this;
  }