/* Copyright 2006 by Sean Luke and George Mason University Licensed under the Academic Free License version 3.0 See the file "LICENSE" for more information */ package sim.display; import sim.engine.*; import sim.portrayal.*; import java.io.*; import sim.util.Bag; /** A wrapper for SimState and Schedule which provides additional functionality for GUI objects. This wrapper extends the functionality of SimState and Schedule through encapsulation, NOT subclassing. Why? Because the general idea is that SimState, and *anything* which hangs off of it, should be serializable out to a checkpoint and not know or care about whether or not it's running under a GUI or running headless.

Displays and Controllers (such as Display2D and the Console) do not care about the SimState, and make precious few calls to the Schedule. Instead, they generally only work with you through the GUIState class.

GUIState has the same start() and finish() methods as SimState, and indeed the default forms of these methods just call start() and finish() on the underlying SimState. Additionally, GUIState has init(Controller) and quit() methods. The init(Controller) method sets up the GUIState to work in an environment controlled by the specified Controller. The quit() method is called to tell the GUIState to shut down and free any of its resources (perhaps the simulation document is being closed in the GUI, or the GUI is quitting).

GUIState also has two methods used by the Controller to specify things about it. In particular, public static String getName(Class class) should return an intelligent name for the simulation, and public static Object getInfo(Class class) should return an HTML or textual description of the simulation either as a URL or a String.

You can create a global inspector for your model (as opposed to the individual per-object inspectors created by various portrayals). This is done by overriding either getInspector() or getSimulationInspectedObject().

GUIState has a wrapper step() method which in turn calls the Schedule's step(state) method. However, this wrapper provides a hook for objects such as displays to schedule themselves without using the Schedule. This hook is the scheduleImmediate(...) and scheduleImmediateRepeat(...) methods. There is also a reset() method which resets both the immediates and the underlying Schedule.

Last, GUIState has a wrapper function to make it convenient to read in a new SimState from a serialized file: readNewStateFromCheckpoint(). This function checks to see if the serialized file is valid for this simulation. To do this, it calls validSimState(), which is a hook that you should override to return TRUE if the provided state is a valid SimState for your simulation (usually this means that it's the right subclass of SimState for your purposes).

Generally speaking, if you have access to a GUIState, you should use GUIstate methods start(), finish(), step(), reset(), and readNewStateFromCheckpoint() instead of the underlying methods in the SimState and Controller. Otherwise, feel free to use the underlying methods (such as Schedule.time()).

Exception Handling. It's a common error to schedule a null event, or one with an invalid time. Like Schedule, GUIState previously returned false or null in such situations, but this leaves the burden on the programmer to check, and programmers are forgetful! We have changed GUIState and Schedule to throw exceptions by default instead. You can change them both back to returning false or null (perhaps if you want to handle the situations yourself more efficiently than atching an exception, or if you know what you're doing schedule-wise) by setting Schedule.setThrowingScheduleExceptions(false). */ public abstract class GUIState { /** The underlying SimState */ public SimState state; /** The controller for the GUIState. This field may be null if there is no controller or no controller YET */ public Controller controller; /** A bag of objects containing objects that may be needed at various times */ public Bag guiObjects; /** Override this constructor in your subclass to call super(state) where state is a properly constructed SimState appropriate to your problem -- do NOT call super()*/ private GUIState() { } /** You may optionally override this constructor to call super(state) but you should be sure to override the no-argument GUIState() constructor as stipulated. */ protected GUIState(SimState state) { this.state = state; resetQueues(); } /** Returns the short name of the class. If the Class is foo.bar.baz.Quux, then Quux is returned. */ public static String getTruncatedName(Class theClass) { // do the default if (theClass==null) return ""; String fullName = theClass.getName(); int lastPeriod = fullName.lastIndexOf("."); return fullName.substring(lastPeriod + 1); // nifty, works even if lastPeriod = -1 } /** Call this method to get the simulation name for any class. If a class does not implement getName(), then the fully qualified classname is used instead. To provide a descriptive name for your class, override getName(). */ public final static String getName(Class theClass) { if (theClass == null) return ""; try { java.lang.reflect.Method m = theClass.getMethod("getName", (Class[])null); if (m.getDeclaringClass().equals(GUIState.class)) // it wasn't overridden return getTruncatedName(theClass); else return (String)(m.invoke(null,(Object[])null)); } catch (NoSuchMethodException e) { e.printStackTrace(); return getTruncatedName(theClass); } catch (Throwable e) { e.printStackTrace(); return "Error in retrieving simulation name"; } } /** Override this method in your subclass to provide a descriptive name for your simulation; otherwise the default will be used: the short classname (that is, if your class is foo.bar.Baz, Baz will be used). That might not be very descriptive!

Notice that this is a static method, and yet you're overriding it as if it were an instance method. This is because the method getInfo(Class) uses reflection to call the proper method on a per-class basis. Like magic! */ public static String getName() { return "This is GUIState's getName() method. It probably shouldn't have been called."; } static Object doDefaultInfo(Class theClass) { java.net.URL url = theClass.getResource("index.html"); if (url == null) return ""; else return url; } /** Returns either a String or a URL which provides descriptive information about the simulation hosted by the given class (which should be a GUIState subclass). To change the information string about your own simulation, override the getInfo() method instead. If you don't override this method, MASON will look for a file called "index.html" in the same directory as the class file and use that. However if this then fails, Java will hunt for any "index.html" file and use that instead -- that's probably not what you wanted. Long story short, either override the getInfo() method, or provide an "index.html" file. */ public final static Object getInfo(Class theClass) { if (theClass == null) return ""; try { java.lang.reflect.Method m = theClass.getMethod("getInfo", (Class[])null); if (m.getDeclaringClass().equals(GUIState.class)) // it wasn't overridden return doDefaultInfo(theClass); else return m.invoke(null,(Object[])null); } catch (NoSuchMethodException e) { return doDefaultInfo(theClass); } catch (Throwable e) { e.printStackTrace(); return "Error in retrieving simulation info"; } } /** Override this method with a static method of your own in your subclass to provide an object (a URL or a String) describing information about your simulation; if you do not override this method, then the system will look for a file called index.html located next to your .class file and use a URL to that file as the information. If there is no such file, Java may then go on a hunting expedition to find and return some file called index.html in your CLASSPATH; this is probably not what you intended, but we can't easily prevent it. If there's absolutely no such file, getInfo() will return a blank HTML page.

Notice that this is a static method, and yet you're overriding it as if it were an instance method. This is because the method getInfo(Class) uses reflection to call the proper method on a per-class basis. Like magic! */ public static Object getInfo() { return "This is GUIState's getInfo() method. It probably shouldn't have been called."; } /** By default returns a non-volatile Inspector which wraps around getSimulationInspectedObject(); if getSimulationInspectedObject() returns null, then getInspector() will return null also. Override this to provide a custom inspector as you see fit. */ public Inspector getInspector() { Object object = getSimulationInspectedObject(); if (object == null) return null; Inspector i = new SimpleInspector(object, this); i.setVolatile(false); return i; } /** Returns an object with various property methods (getFoo(...), isFoo(...), setFoo(...)) whose properties will be accessible by the user. This gives you an easy way to allow the user to set certain global properties of your model from the GUI. If null is returned (the default), then nothing will be displayed to the user. One trick you should know about your object: it should be public, as well its property methods, and if it's anonymous, it should not introduce any property methods not defined in its superclass. Otherwise Java's reflection API can't access those methods -- they're considered private. GUIState also supports sim.util.Properties's domFoo(...) domain declarations to allow for sliders and pop-up lists.*/ public Object getSimulationInspectedObject() { return null; } /** Use Inspector.isVolatile() instead. This method returns getInspector().isVolatile(). This is an expensive method and you should not use it. @deprecated */ public boolean isInspectorVolatile() { return getInspector().isVolatile(); } /** Called to initialize (display) windows etc. You can use this to set up the windows, then register them with the Controller so it can manage hiding, showing, and moving them. The default version of this method simply calls this.controller=controller; */ public void init(Controller controller) { this.controller = controller; } /** Called immediately prior to starting the simulation, or in-between simulation runs. Ordinarily, you wouldn't need to override this hook. */ boolean started = false; public void start() { started = true; state.start(); // schedule the global inspector if there is one // run the start queue stuff synchronized(state.schedule) { // execute the start queue Steppable[] _start2 = start2; System.arraycopy(start,0,start2,0,startSize); int _startSize = startSize; startSize = 0; // do the start stuff for(int x=0;x<_startSize;x++) _start2[x].step(state); } } /** Called either at the proper or a premature end to the simulation. If the user quits the program, this function may not be called. Ordinarily, you wouldn't need to override this hook. Does nothing if the GUIState hasn't been started or loaded yet. */ public void finish() { if (!started) return; // no reason to call synchronized(state.schedule) { // execute the finish queue Steppable[] _finish2 = finish2; System.arraycopy(finish,0,finish2,0,finishSize); int _finishSize = finishSize; finishSize = 0; // do the finish stuff for(int x=0;x<_finishSize;x++) _finish2[x].step(state); } state.finish(); resetQueues(); started = false; } /** Called by the Console when the user is quitting the SimState. A good place to stick stuff that you'd ordinarily put in a finalizer -- finalizers are tenuous at best. So here you'd put things like the code that closes the relevant display windows etc.*/ public void quit() { } /** This method should be set to return TRUE if state can be validly used -- mostly likely all you need to check is that it's the right class for this simulation. The default returns TRUE if state is non-null and the same class as the current state; that's often sufficient. */ public boolean validSimState(SimState state) { return (state != null && state.getClass().equals(this.state.getClass())); } /** Called by the Console when the user is loading in a new state from a checkpoint. The new state is passed in as an argument. The default version simply calls finish(), then sets this.state to the new state. You should override this, calling super.load(state) first, to reset your portrayals etc. to reflect the new state. state.start() will NOT be called. Thus anything you handled in start() that needs to be reset to accommodate the new state should be handled here. We recommend that you call repaint() on any Display2Ds. */ public void load(SimState state) { this.state = state; started = true; // just in case // schedule the global inspector if there is one // run the start queue stuff synchronized(state.schedule) { // execute the start queue Steppable[] _start2 = start2; System.arraycopy(start,0,start2,0,startSize); int _startSize = startSize; startSize = 0; // do the start stuff for(int x=0;x<_startSize;x++) _start2[x].step(state); } } /** Loads a new SimState from the provided file. Do not call this in an unthreadsafe situation -- it doesn't check. Returns false if the state was not valid. Returns various errors if bad things occurred trying to serialize in from the checkpoint. If false is returned or an error is thrown, the old SimState is retained. */ public boolean readNewStateFromCheckpoint(File file) throws IOException, ClassNotFoundException, OptionalDataException, ClassCastException, Exception { FileInputStream f = new FileInputStream(file); SimState state = SimState.readFromCheckpoint(f); f.close(); if (!validSimState(state)) return false; finish(); // let it clean up load(state); return true; } // the before and after queues protected Steppable[] before; Steppable[] before2; protected int beforeSize; protected Steppable[] after; Steppable[] after2; protected int afterSize; // the start and finish queues Steppable[] start; Steppable[] start2; int startSize; Steppable[] finish; Steppable[] finish2; int finishSize; /** Don't call this unless you know what you're doing. */ protected void resetQueues() { before = new Steppable[11]; before2 = new Steppable[11]; beforeSize = 0; after = new Steppable[11]; after2 = new Steppable[11]; afterSize = 0; start = new Steppable[11]; start2 = new Steppable[11]; startSize = 0; finish = new Steppable[11]; finish2 = new Steppable[11]; finishSize = 0; } /** Empties out the schedule and resets it to a pristine state BEFORE_SIMULATION. If you're using a GUIState, you should call this version instead of Schedule's version. */ public synchronized final void reset(SimState state) { state.schedule.reset(); resetQueues(); } /** Returns FALSE if nothing was stepped -- the schedule is exhausted or time has run out. */ public boolean step() { boolean returnval = false; synchronized(state.schedule) { // grab the before and after queues so no one add to them // while we're using them. Steppable[] _before2 = before2; Steppable[] _after2 = after2; System.arraycopy(before,0,before2,0,beforeSize); System.arraycopy(after,0,after2,0,afterSize); int _beforeSize = beforeSize; int _afterSize = afterSize; afterSize = 0; beforeSize = 0; // do the before stuff first for(int x=0;x<_beforeSize;x++) _before2[x].step(state); // step the schedule returnval = state.schedule.step(state); // do the after stuff for(int x=0;x<_afterSize;x++) _after2[x].step(state); } return returnval; } /** Roughly doubles the array size, retaining the existing elements */ protected Steppable[] increaseSubsteps(Steppable[] substeps) { Steppable[] newsubstep = new Steppable[substeps.length*2+1]; System.arraycopy(substeps,0,newsubstep,0,substeps.length); return newsubstep; } /** Schedules an item to occur (in no particular order) immediately before or immediately after the schedule is stepped on the next time step (not including blank steps). Pass in FALSE to indicate you want to be immediately BEFORE the next timestep; pass in TRUE if you want to be immediately AFTER the next time step (the more common situation). Returns false if the current time is AFTER_SIMULATION or if the event is null.

Why would you use this method? Primarily to get things scheduled which aren't stored in the Schedule itself, so it can be serialized out without them. */ public boolean scheduleImmediate(boolean immediatelyAfter, Steppable event) { synchronized(state.schedule) { if (event == null || state.schedule.time() >= Schedule.AFTER_SIMULATION) { if (event == null) { throw new IllegalArgumentException("The provided Steppable is null"); } else if (state.schedule.time() >= Schedule.AFTER_SIMULATION) { throw new IllegalArgumentException("The simulation is over and the item cannot be scheduled."); } } if (immediatelyAfter) { if (afterSize == after.length) { after = increaseSubsteps(after); after2 = new Steppable[after.length]; } after[afterSize++] = event; } else { if (beforeSize == before.length) { before = increaseSubsteps(before); before2 = new Steppable[before.length]; } before[beforeSize++] = event; } } return true; } /** Schedules an item to occur (in no particular order) immediately before or immediately after all future steps the Schedule takes (not including blank steps). Pass in FALSE to indicate you want to be immediately BEFORE the next timestep; pass in TRUE if you want to be immediately AFTER the next time step (the more common situation). Returns a Stoppable, or null if the current time is AFTER_SIMULATION or if the event is null. The recurrence will continue until state.schedule.time() >= AFTER_SIMULATION, state.schedule is cleared out, or the Stoppable's stop() method is called, whichever happens first.

Why would you use this method? Primarily to get things scheduled which aren't stored in the Schedule itself, so it can be serialized out without them. */ public Stoppable scheduleImmediateRepeat(boolean immediatelyAfter, Steppable event) { // if (event == null) return null; // no need to check because scheduleImmediate does already Repeat r = new Repeat(immediatelyAfter, event); if (scheduleImmediate(immediatelyAfter, r)) return r; else return null; } /** Schedules an item to occur when the user starts or stops the simulator, or when it stops on its own accord. If atEnd is TRUE, then the item is scheduled to occur when the finish() method is executed. If atEnd is FALSE, then the item is scheduled to occur when the start() method is executed. Returns true if scheduling succeeded. @deprecated use scheduleAtStart and scheduleAtEnd instead */ public boolean scheduleAtExtreme(Steppable event, boolean atEnd) { return _scheduleAtExtreme(event, atEnd); } // this has been pulled out to avoid deprecation warnings for scheduleAtStart and scheduleAtEnd boolean _scheduleAtExtreme(Steppable event, boolean atEnd) { synchronized(state.schedule) { if (event == null || state.schedule.time() >= Schedule.AFTER_SIMULATION) { if (event == null) { throw new IllegalArgumentException("The provided Steppable is null"); } else if (state.schedule.time() >= Schedule.AFTER_SIMULATION) { throw new IllegalArgumentException("The simulation is over and the item cannot be scheduled."); } } if (atEnd) { if (finishSize == finish.length) { finish = increaseSubsteps(finish); finish2 = new Steppable[finish.length]; } finish[finishSize++] = event; } else { if (startSize == start.length) { start = increaseSubsteps(start); start2 = new Steppable[start.length]; } start[startSize++] = event; } } return true; } /** Schedules an item to occur when the user starts the simulator (when the start() method is executed) or loads one (when load() is executed). Identical to scheduleAtExtreme(event,false). Returns true if scheduling succeeded. */ public boolean scheduleAtStart(Steppable event) { return _scheduleAtExtreme(event,false); } /** Schedules an item to occur when the user stops the simulator (when the stop() method is executed), when it stops on its own accord, or when the user has load()ed another simulation to replace it. Identical to scheculeAtExtreme(event,false). Returns true if scheduling succeeded. */ public boolean scheduleAtEnd(Steppable event) { return _scheduleAtExtreme(event,true); } /** Handles repeated steps. This is done by wrapping the Steppable with a Repeat object which is itself Steppable, and on its step calls its subsidiary Steppable, then reschedules itself. Repeat is stopped by setting its subsidiary to null, and so the next time it's scheduled it won't reschedule itself (or call the subsidiary). A private class for GUIState. Notice almost exactly the same as Schedule.Repeat. */ class Repeat implements Steppable, Stoppable { protected boolean immediatelyAfter; protected Steppable step; // if null, does not reschedule public Repeat(boolean immediatelyAfter, Steppable step) { this.immediatelyAfter = immediatelyAfter; this.step = step; } public synchronized void step(SimState state) { if (step!=null) { try { scheduleImmediate(immediatelyAfter,this); } catch (IllegalArgumentException e) { /* Only occurs if time has run out */} step.step(state); } } public synchronized void stop() { step = null; } } }