Package ptolemy.domains.csp.demo.BusContention

Class BusContentionApplet

  • All Implemented Interfaces:
    java.awt.image.ImageObserver, java.awt.MenuContainer, java.io.Serializable, javax.accessibility.Accessible, javax.swing.RootPaneContainer, ExecutionListener
    public class BusContentionApplet
extends PtolemyApplet
    A model of hardware subsystems accessing a shared resource using rendezvous. The model shows the use of timed CSP to deterministically handle nondeterministic events.

    The applet consists of a controller, three processors and a memory block. At randomly selected points in time, each processor can request permission from the controller to access the memory. The processors each have priorities associated with them, and in cases where there is a simultaneous memory access request, the controller grants permission to the processor with the highest priority.

    All communication between actors in a CSP model of computation occurs via rendezvous. Rendezvous is an atomic form of communication. This model uses a timed extension to CSP, so each rendezvous logically occurs at a specific point in time.

    Because of the atomic nature of rendezvous, when the controller receives a request for access, it cannot know whether there is another, higher priority request pending at the same time. To overcome this difficulty, an alarm is employed. The alarm is started by the controller immediately following the first request for memory access. It is awakened when time is ready to advance (the model blocks on delays). This indicates to the controller that no more memory requests will occur at the given point in time. Hence, the alarm uses centralized time to make deterministic an inherently non-deterministic activity.

    In the applet, each of the initially blue processors (the circular nodes) can be in one of three states. The color yellow indicates that a processor is in state 1 and is waiting for the controller to give it permission to access memory. The color green indicates that a processor has been granted permission to access memory. The color red indicates that the processor has been denied memory access.

    Since:
    Ptolemy II 0.3
    Version:
    $Id$
    Author:
    John S. Davis II, Michael Shilman
    See Also:
    Serialized Form
    Pt.AcceptedRating:
    Red (cxh)
    Pt.ProposedRating:
    Red (eal)

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  BusContentionApplet.BusContentionGraphController  
      static class  BusContentionApplet.LocalEdgeRenderer
      LocalEdgeRenderer draws arrowheads on both ends of the connector
      class  BusContentionApplet.StateListener
      StateListener is an inner class that listens to state events on the Ptolemy kernel and changes the color of the nodes appropriately.
      static class  BusContentionApplet.ThreadRenderer
      ThreadRenderer draws the nodes to represent running threads.

      • Nested classes/interfaces inherited from class javax.swing.JApplet

        javax.swing.JApplet.AccessibleJApplet

      • Nested classes/interfaces inherited from class java.applet.Applet

        java.applet.Applet.AccessibleApplet

      • Nested classes/interfaces inherited from class java.awt.Panel

        java.awt.Panel.AccessibleAWTPanel

      • Nested classes/interfaces inherited from class java.awt.Container

        java.awt.Container.AccessibleAWTContainer

      • Nested classes/interfaces inherited from class java.awt.Component

        java.awt.Component.AccessibleAWTComponent, java.awt.Component.BaselineResizeBehavior, java.awt.Component.BltBufferStrategy, java.awt.Component.FlipBufferStrategy

    • Field Summary

      • Fields inherited from class javax.swing.JApplet

        accessibleContext, rootPane, rootPaneCheckingEnabled

      • Fields inherited from class java.awt.Component

        BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

      • Fields inherited from interface java.awt.image.ImageObserver

        ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected NamedObj _createModel​(Workspace workspace)
      Create a model.
      protected void _createView()
      Create an animation pane.
      void start()
      Override the baseclass start method so that the model does not immediately begin executing as soon as the the applet page is displayed.

      • Methods inherited from class javax.swing.JApplet

        addImpl, createRootPane, getAccessibleContext, getContentPane, getGlassPane, getGraphics, getJMenuBar, getLayeredPane, getRootPane, getTransferHandler, isRootPaneCheckingEnabled, paramString, remove, repaint, setContentPane, setGlassPane, setJMenuBar, setLayeredPane, setLayout, setRootPane, setRootPaneCheckingEnabled, setTransferHandler, update

      • Methods inherited from class java.applet.Applet

        getAppletContext, getAudioClip, getAudioClip, getCodeBase, getDocumentBase, getImage, getImage, getLocale, getParameter, isActive, isValidateRoot, newAudioClip, play, play, resize, resize, setStub, showStatus

      • Methods inherited from class java.awt.Panel

        addNotify

      • Methods inherited from class java.awt.Container

        add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getMousePosition, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paint, paintComponents, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, removeAll, removeContainerListener, removeNotify, setComponentZOrder, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, transferFocusDownCycle, validate, validateTree

      • Methods inherited from class java.awt.Component

        action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    • Constructor Detail

      • BusContentionApplet

        public BusContentionApplet()

    • Method Detail

      • _createModel

        protected NamedObj _createModel​(Workspace workspace)
                         throws java.lang.Exception
        Create a model.
        Overrides:
        _createModel in class PtolemyApplet
        Parameters:
        workspace - The workspace in which to create the model.
        Returns:
        A model.
        Throws:
        java.lang.Exception - If something goes wrong. This is a broad exception to allow derived classes wide lattitude as to which exception to throw.

      • start

        public void start()
        Override the baseclass start method so that the model does not immediately begin executing as soon as the the applet page is displayed. Execution begins once the "Go" button is depressed. Layout the graph visualization, since this can't be done in the init method, because the graph hasn't yet been displayed.
        Overrides:
        start in class PtolemyApplet