rootfinderpanel.java

来自「一个一元曲线多项式数值演示例子」· Java 代码 · 共 320 行

package numbercruncher.rootutils;

import java.awt.*;
import java.awt.event.*;

import numbercruncher.graphutils.*;

/**
 * The base panel for all root finder demo panels.
 */
public abstract class RootFinderPanel
    extends GraphPanel {
  /** control panel */
  protected Panel controlPanel = new Panel();
  /** n label */
  protected Label nLabel = new Label();
  /** n text */
  protected Label nText = new Label();
  /** run button */
  protected Button runButton = new Button("Run");
  /** step button */
  protected Button stepButton = new Button("Step");

  /** function image file name */
  private String functionImageFileName;
  /** function frame */
  private FunctionFrame functionFrame;
  /** function frame title */
  private String functionFrameTitle;

  /** array of functions
      to find roots for */private PlotFunction plotFunctions[];
  /** selected function */
  private PlotFunction plotFunction;

  /** thread for automatic stepping */
  private Thread runThread = null;

  /** true if pause button was pressed */
  private boolean paused = false;
  /** true if algorithm converged */
  private boolean converged = false;

  /**
   * Constructor.
   * @param plotFunctions the array of functions to plot
   * @param functionImageFileName the function image file name
   * @param functionFrameTitle the function frame title
   */
  protected RootFinderPanel(PlotFunction plotFunctions[],
                            String functionImageFileName,
                            String functionFrameTitle) {
    this(plotFunctions, true, false,
         functionImageFileName, functionFrameTitle);
  }

  /**
   * Constructor.
   * @param plotFunctions the array of functions to plot
   * @param xorMode true to set XORMode
   * @param functionImageFileName the function image file name
   * @param functionFrameTitle the function frame title
   */
  protected RootFinderPanel(PlotFunction plotFunctions[],
                            boolean xorMode,
                            String functionImageFileName,
                            String functionFrameTitle) {
    this(plotFunctions, xorMode, false,
         functionImageFileName, functionFrameTitle);
  }

  /**
   * Constructor.
   * @param plotFunctions the array of functions to plot
   * @param xorMode true to set XORMode
   * @param drawXequalsY true to draw X=Y line
   * @param functionImageFileName the function image file name
   * @param functionFrameTitle the function frame title
   */
  protected RootFinderPanel(PlotFunction plotFunctions[],
                            boolean xorMode,
                            boolean drawXequalsY,
                            String functionImageFileName,
                            String functionFrameTitle) {
    super(plotFunctions, plotFunctions[0].getPlotProperties(),
          xorMode, drawXequalsY);

    this.plotFunctions = plotFunctions;
    this.plotFunction = plotFunctions[0];
    this.functionImageFileName = functionImageFileName;
    this.functionFrameTitle = functionFrameTitle;

    Font labelFont = getLabelFont();
    Font textFont = getTextFont();

    nLabel.setFont(labelFont);
    nLabel.setAlignment(Label.RIGHT);
    nLabel.setText("n:");
    nText.setFont(textFont);
    nText.setAlignment(Label.LEFT);
    nText.setText(" ");

    runButton.setEnabled(true);
    stepButton.setEnabled(true);

    // Step button handler.
    stepButton.addActionListener(new ActionListener() {
      // If the run thread is inactive, call step().
      // If the thread is active, stop it and revert the
      // button label to "Step".
      public void actionPerformed(ActionEvent ev) {
        if ( (runThread != null) && (runThread.isAlive())) {
          paused = true;
          runButton.setEnabled(true);
          stepButton.setLabel("Step");
        }
        else {
          step();
        }
      }
    });

    // Run button handler.
    runButton.addActionListener(new ActionListener() {
      // Start the run thread and change the step button
      // label to "Pause".
      public void actionPerformed(ActionEvent ev) {
        runButton.setEnabled(false);
        stepButton.setLabel("Pause");
        paused = false;

        runThread = new RunThread();
        runThread.start();
      }
    });
  }

  /**
   * Set the converged flag.
   * @param converged true if algorithm converged
   */
  public void setConverged(boolean converged) {
    this.converged = converged;
  }

  /**
   * Open the function frame.
   */
  private void openFunctionFrame() {
    functionFrame = new FunctionFrame(plotFunctions, functionImageFileName,
                                      functionFrameTitle, this);
    functionFrame.setVisible(true);

    setHeaderImage(functionFrame.getImage());
    setFunction(plotFunctions[0]);
  }

  /**
   * Choose a function. (Callback from the function frame.)
   */
  public void chooseFunction(int index) {
    plotFunction = plotFunctions[index];
    setFunction(plotFunction);
    draw();
  }

  /**
   * Return the selected function to find roots for.
   * @return the selected function
   */
  protected PlotFunction getSelectedPlotFunction() {
    return plotFunction;
  }

  //-----------------------------//
  // GraphPanel method overrides //
  //-----------------------------//

  /**
   * Create the function frame or bring it to the front.
   * (Callback from header panel.)
   */
  public void doHeaderAction() {
    if (functionFrame != null) {
      functionFrame.toFront();
    }
    else {
      openFunctionFrame();
    }
  }

  /**
   * Return the value of the selected function at x.
   * @param x the value of x
   * @return the value of the function
   */
  public float valueAt(float x) {
    return plotFunction.at(x);
  }

  /**
   * Notification that the plot bounds changed.
   * Redraw the panel.
   */
  public void plotBoundsChanged() {
    draw();
  }

  /**
   * Notification that a user input error occurred.
   * Disable the run and step buttons.
   */
  protected void userErrorOccurred() {
    runButton.setEnabled(false);
    stepButton.setEnabled(false);
  }

  /**
   * Draw the contents the panel.
   */
  public void draw() {
    // Stop the run thread.
    paused = true;
    converged = false;

    // Reinitialize the run and step buttons.
    runButton.setEnabled(true);
    stepButton.setEnabled(true);
    stepButton.setLabel("Step");

    setHeaderDisplay(plotFunction);
    super.draw();
  }

  //--------------------------//
  // DemoPanel implementation //
  //--------------------------//

  /**
   * Initialize the demo. (Callback from applet.)
   */
  public void initializeDemo() {
    openFunctionFrame();
  }

  /**
   * Close the demo. (Callback from applet.)
   */
  public void closeDemo() {
    if (functionFrame != null) {
      functionFrame.setVisible(false);
      functionFrame.dispose();
      functionFrame = null;
    }
  }

  //---------------------//
  // Algorithm animation //
  //---------------------//

  /**
   * One iteration step.  Do nothing here.
   */
  protected void step() {}

  /**
   * The thread that automatically steps once per half second.
   */
  private class RunThread
      extends Thread {
    /**
     * Run the thread.
     */
    public void run() {
      // Loop until the iteration count stops.
      while ( (!paused) && (!converged)) {
        step();

        try {
          sleep(500); // half second
        }
        catch (Exception ex) {}
      }

      // Unless it's only paused, disable this function.
      if (!paused) {
        runButton.setEnabled(false);
        stepButton.setEnabled(false);
        stepButton.setLabel("Step");
      }
    }
  }

  /**
   * The algorithm successfully converged.
   */
  protected void successfullyConverged() {
    converged = true;

    runButton.setEnabled(false);
    stepButton.setEnabled(false);
  }

  /**
   * The algorithm has exceeded the maximum number of iterations.
   * @param maxIters the maximum number of iterations
   * @param text the text to star out
   */
  protected void iterationLimitExceeded(int maxIters, Label text) {
    converged = false;
    paused = true; // stop the run thread

    nText.setText(">" + maxIters + " ITERS");
    text.setText("***");

    runButton.setEnabled(false);
    stepButton.setEnabled(false);
  }
}