applets/SpreadSheet/SpreadSheet.java

/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */


import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;


@SuppressWarnings("serial")
public class SpreadSheet extends Applet implements MouseListener, KeyListener {

    String title;
    Font titleFont;
    Color cellColor;
    Color inputColor;
    int cellWidth = 100;
    int cellHeight = 15;
    int titleHeight = 15;
    int rowLabelWidth = 15;
    Font inputFont;
    boolean isStopped = false;
    boolean fullUpdate = true;
    int rows;
    int columns;
    int currentKey = -1;
    int selectedRow = -1;
    int selectedColumn = -1;
    SpreadSheetInput inputArea;
    Cell cells[][];
    Cell current = null;

    @Override
    public synchronized void init() {
        String rs;

        cellColor = Color.white;
        inputColor = new Color(100, 100, 225);
        inputFont = new Font("Monospaced", Font.PLAIN, 10);
        titleFont = new Font("Monospaced", Font.BOLD, 12);
        title = getParameter("title");
        if (title == null) {
            title = "Spreadsheet";
        }
        rs = getParameter("rows");
        if (rs == null) {
            rows = 9;
        } else {
            rows = Integer.parseInt(rs);
        }
        rs = getParameter("columns");
        if (rs == null) {
            columns = 5;
        } else {
            columns = Integer.parseInt(rs);
        }
        cells = new Cell[rows][columns];
        char l[] = new char[1];
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {

                cells[i][j] = new Cell(this,
                        Color.lightGray,
                        Color.black,
                        cellColor,
                        cellWidth - 2,
                        cellHeight - 2);
                l[0] = (char) ((int) 'a' + j);
                rs = getParameter("" + new String(l) + (i + 1));
                if (rs != null) {
                    cells[i][j].setUnparsedValue(rs);
                }
            }
        }

        Dimension d = getSize();
        inputArea = new SpreadSheetInput(null, this, d.width - 2, cellHeight - 1,
                inputColor, Color.white);
        resize(columns * cellWidth + rowLabelWidth,
                (rows + 3) * cellHeight + titleHeight);
        addMouseListener(this);
        addKeyListener(this);
    }

    public void setCurrentValue(float val) {
        if (selectedRow == -1 || selectedColumn == -1) {
            return;
        }
        cells[selectedRow][selectedColumn].setValue(val);
        repaint();
    }

    @Override
    public void stop() {
        isStopped = true;
    }

    @Override
    public void start() {
        isStopped = false;
    }

    @Override
    public void destroy() {
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {
                if (cells[i][j].type == Cell.URL) {
                    cells[i][j].updaterThread.run = false;
                }
            }
        }
    }

    public void setCurrentValue(int type, String val) {
        if (selectedRow == -1 || selectedColumn == -1) {
            return;
        }
        cells[selectedRow][selectedColumn].setValue(type, val);
        repaint();
    }

    @Override
    public void update(Graphics g) {
        if (!fullUpdate) {
            int cx, cy;

            g.setFont(titleFont);
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < columns; j++) {
                    if (cells[i][j].needRedisplay) {
                        cx = (j * cellWidth) + 2 + rowLabelWidth;
                        cy = ((i + 1) * cellHeight) + 2 + titleHeight;
                        cells[i][j].paint(g, cx, cy);
                    }
                }
            }
        } else {
            paint(g);
            fullUpdate = false;
        }
    }

    public void recalculate() {
        int i, j;

        //System.out.println("SpreadSheet.recalculate");
        for (i = 0; i < rows; i++) {
            for (j = 0; j < columns; j++) {
                if (cells[i][j] != null && cells[i][j].type == Cell.FORMULA) {
                    cells[i][j].setRawValue(evaluateFormula(
                            cells[i][j].parseRoot));
                    cells[i][j].needRedisplay = true;
                }
            }
        }
        repaint();
    }

    float evaluateFormula(Node n) {
        float val = 0.0f;

        //System.out.println("evaluateFormula:");
        //n.print(3);
        if (n == null) {
            //System.out.println("Null node");
            return val;
        }
        switch (n.type) {
            case Node.OP:
                val = evaluateFormula(n.left);
                switch (n.op) {
                    case '+':
                        val += evaluateFormula(n.right);
                        break;
                    case '*':
                        val *= evaluateFormula(n.right);
                        break;
                    case '-':
                        val -= evaluateFormula(n.right);
                        break;
                    case '/':
                        val /= evaluateFormula(n.right);
                        break;
                }
                break;
            case Node.VALUE:
                //System.out.println("=>" + n.value);
                return n.value;
            case Node.CELL:
                if (cells[n.row][n.column] == null) {
                    //System.out.println("NULL at 193");
                } else {
                    //System.out.println("=>" + cells[n.row][n.column].value);
                    return cells[n.row][n.column].value;
                }
        }

        //System.out.println("=>" + val);
        return val;
    }

    @Override
    public synchronized void paint(Graphics g) {
        int i, j;
        int cx, cy;
        char l[] = new char[1];


        Dimension d = getSize();

        g.setFont(titleFont);
        i = g.getFontMetrics().stringWidth(title);
        g.drawString((title == null) ? "Spreadsheet" : title,
                (d.width - i) / 2, 12);
        g.setColor(inputColor);
        g.fillRect(0, cellHeight, d.width, cellHeight);
        g.setFont(titleFont);
        for (i = 0; i < rows + 1; i++) {
            cy = (i + 2) * cellHeight;
            g.setColor(getBackground());
            g.draw3DRect(0, cy, d.width, 2, true);
            if (i < rows) {
                g.setColor(Color.red);
                g.drawString("" + (i + 1), 2, cy + 12);
            }
        }

        g.setColor(Color.red);
        cy = (rows + 3) * cellHeight + (cellHeight / 2);
        for (i = 0; i < columns; i++) {
            cx = i * cellWidth;
            g.setColor(getBackground());
            g.draw3DRect(cx + rowLabelWidth,
                    2 * cellHeight, 1, d.height, true);
            if (i < columns) {
                g.setColor(Color.red);
                l[0] = (char) ((int) 'A' + i);
                g.drawString(new String(l),
                        cx + rowLabelWidth + (cellWidth / 2),
                        cy);
            }
        }

        for (i = 0; i < rows; i++) {
            for (j = 0; j < columns; j++) {
                cx = (j * cellWidth) + 2 + rowLabelWidth;
                cy = ((i + 1) * cellHeight) + 2 + titleHeight;
                if (cells[i][j] != null) {
                    cells[i][j].paint(g, cx, cy);
                }
            }
        }

        g.setColor(getBackground());
        g.draw3DRect(0, titleHeight,
                d.width,
                d.height - titleHeight,
                false);
        inputArea.paint(g, 1, titleHeight + 1);
    }

    //1.1 event handling
    @Override
    public void mouseClicked(MouseEvent e) {
    }

    @Override
    public void mousePressed(MouseEvent e) {
        int x = e.getX();
        int y = e.getY();
        Cell cell;
        if (y < (titleHeight + cellHeight)) {
            selectedRow = -1;
            if (y <= titleHeight && current != null) {
                current.deselect();
                current = null;
            }
            e.consume();
        }
        if (x < rowLabelWidth) {
            selectedRow = -1;
            if (current != null) {
                current.deselect();
                current = null;
            }
            e.consume();

        }
        selectedRow = ((y - cellHeight - titleHeight) / cellHeight);
        selectedColumn = (x - rowLabelWidth) / cellWidth;
        if (selectedRow > rows
                || selectedColumn >= columns) {
            selectedRow = -1;
            if (current != null) {
                current.deselect();
                current = null;
            }
        } else {
            if (selectedRow >= rows) {
                selectedRow = -1;
                if (current != null) {
                    current.deselect();
                    current = null;
                }
                e.consume();
            }
            if (selectedRow != -1) {
                cell = cells[selectedRow][selectedColumn];
                inputArea.setText(cell.getPrintString());
                if (current != null) {
                    current.deselect();
                }
                current = cell;
                current.select();
                requestFocus();
                fullUpdate = true;
                repaint();
            }
            e.consume();
        }
    }

    @Override
    public void mouseReleased(MouseEvent e) {
    }

    @Override
    public void mouseEntered(MouseEvent e) {
    }

    @Override
    public void mouseExited(MouseEvent e) {
    }

    @Override
    public void keyPressed(KeyEvent e) {
    }

    @Override
    public void keyTyped(KeyEvent e) {
        fullUpdate = true;
        inputArea.processKey(e);
        e.consume();
    }

    @Override
    public void keyReleased(KeyEvent e) {
    }

    @Override
    public String getAppletInfo() {
        return "Title: SpreadSheet \nAuthor: Sami Shaio \nA simple spread sheet.";
    }

    @Override
    public String[][] getParameterInfo() {
        String[][] info = {
            { "title", "string",
                "The title of the spread sheet.  Default is 'Spreadsheet'" },
            { "rows", "int", "The number of rows.  Default is 9." },
            { "columns", "int", "The number of columns.  Default is 5." }
        };
        return info;
    }
}


class CellUpdater extends Thread {

    Cell target;
    InputStream dataStream = null;
    StreamTokenizer tokenStream;
    public volatile boolean run = true;

    public CellUpdater(Cell c) {
        super("cell updater");
        target = c;
    }

    @Override
    public void run() {
        try {
            dataStream = new URL(target.app.getDocumentBase(),
                    target.getValueString()).openStream();
            tokenStream = new StreamTokenizer(new BufferedReader(
                    new InputStreamReader(dataStream)));
            tokenStream.eolIsSignificant(false);

            while (run) {
                switch (tokenStream.nextToken()) {
                    case StreamTokenizer.TT_EOF:
                        dataStream.close();
                        return;
                    default:
                        break;
                    case StreamTokenizer.TT_NUMBER:
                        target.setTransientValue((float) tokenStream.nval);
                        if (!target.app.isStopped && !target.paused) {
                            target.app.repaint();
                        }
                        break;
                }
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    break;
                }
            }
        } catch (IOException e) {
            return;
        }
    }
}


class Cell {

    public static final int VALUE = 0;
    public static final int LABEL = 1;
    public static final int URL = 2;
    public static final int FORMULA = 3;
    Node parseRoot;
    boolean needRedisplay;
    boolean selected = false;
    boolean transientValue = false;
    public int type = Cell.VALUE;
    String valueString = "";
    String printString = "v";
    float value;
    Color bgColor;
    Color fgColor;
    Color highlightColor;
    int width;
    int height;
    SpreadSheet app;
    CellUpdater updaterThread;
    boolean paused = false;

    public Cell(SpreadSheet app,
            Color bgColor,
            Color fgColor,
            Color highlightColor,
            int width,
            int height) {
        this.app = app;
        this.bgColor = bgColor;
        this.fgColor = fgColor;
        this.highlightColor = highlightColor;
        this.width = width;
        this.height = height;
        needRedisplay = true;
    }

    public void setRawValue(float f) {
        valueString = Float.toString(f);
        value = f;
    }

    public void setValue(float f) {
        setRawValue(f);
        printString = "v" + valueString;
        type = Cell.VALUE;
        paused = false;
        app.recalculate();
        needRedisplay = true;
    }

    public void setTransientValue(float f) {
        transientValue = true;
        value = f;
        needRedisplay = true;
        app.recalculate();
    }

    public void setUnparsedValue(String s) {
        switch (s.charAt(0)) {
            case 'v':
                setValue(Cell.VALUE, s.substring(1));
                break;
            case 'f':
                setValue(Cell.FORMULA, s.substring(1));
                break;
            case 'l':
                setValue(Cell.LABEL, s.substring(1));
                break;
            case 'u':
                setValue(Cell.URL, s.substring(1));
                break;
        }
    }

    /**
     * Parse a spreadsheet formula. The syntax is defined as:
     *
     * formula -> value
     * formula -> value op value
     * value -> '(' formula ')'
     * value -> cell
     * value -> <number>
     * op -> '+' | '*' | '/' | '-'
     * cell -> <letter><number>
     */
    public String parseFormula(String formula, Node node) {
        String subformula;
        String restFormula;
        Node left;
        Node right;
        char op;

        if (formula == null) {
            return null;
        }
        subformula = parseValue(formula, node);
        //System.out.println("subformula = " + subformula);
        if (subformula == null || subformula.length() == 0) {
            //System.out.println("Parse succeeded");
            return null;
        }
        if (subformula.equals(formula)) {
            //System.out.println("Parse failed");
            return formula;
        }

        // parse an operator and then another value
        switch (op = subformula.charAt(0)) {
            case 0:
                //System.out.println("Parse succeeded");
                return null;
            case ')':
                //System.out.println("Returning subformula=" + subformula);
                return subformula;
            case '+':
            case '*':
            case '-':
            case '/':
                restFormula = subformula.substring(1);
                subformula = parseValue(restFormula, right = new Node());
                //System.out.println("subformula(2) = " + subformula);
                if (subformula == null ? restFormula != null : !subformula.
                        equals(restFormula)) {
                    //System.out.println("Parse succeeded");
                    left = new Node(node);
                    node.left = left;
                    node.right = right;
                    node.op = op;
                    node.type = Node.OP;
                    //node.print(3);
                    return subformula;
                } else {
                    //System.out.println("Parse failed");
                    return formula;
                }
            default:
                //System.out.println("Parse failed (bad operator): " + subformula);
                return formula;
        }
    }

    public String parseValue(String formula, Node node) {
        char c = formula.charAt(0);
        String subformula;
        String restFormula;
        float _value;
        int row;
        int column;

        //System.out.println("parseValue: " + formula);
        restFormula = formula;
        if (c == '(') {
            //System.out.println("parseValue(" + formula + ")");
            restFormula = formula.substring(1);
            subformula = parseFormula(restFormula, node);
            //System.out.println("rest=(" + subformula + ")");
            if (subformula == null
                    || subformula.length() == restFormula.length()) {
                //System.out.println("Failed");
                return formula;
            } else if (!(subformula.charAt(0) == ')')) {
                //System.out.println("Failed (missing parentheses)");
                return formula;
            }
            restFormula = subformula;
        } else if (c >= '0' && c <= '9') {
            int i;

            //System.out.println("formula=" + formula);
            for (i = 0; i < formula.length(); i++) {
                c = formula.charAt(i);
                if ((c < '0' || c > '9') && c != '.') {
                    break;
                }
            }
            try {
                _value = Float.valueOf(formula.substring(0, i)).floatValue();
            } catch (NumberFormatException e) {
                //System.out.println("Failed (number format error)");
                return formula;
            }
            node.type = Node.VALUE;
            node.value = _value;
            //node.print(3);
            restFormula = formula.substring(i);
            //System.out.println("value= " + value + " i=" + i +
            //                     " rest = " + restFormula);
            return restFormula;
        } else if (c >= 'A' && c <= 'Z') {
            int i;

            column = c - 'A';
            restFormula = formula.substring(1);
            for (i = 0; i < restFormula.length(); i++) {
                c = restFormula.charAt(i);
                if (c < '0' || c > '9') {
                    break;
                }
            }
            row = Float.valueOf(restFormula.substring(0, i)).intValue();
            //System.out.println("row = " + row + " column = " + column);
            node.row = row - 1;
            node.column = column;
            node.type = Node.CELL;
            //node.print(3);
            if (i == restFormula.length()) {
                restFormula = null;
            } else {
                restFormula = restFormula.substring(i);
                if (restFormula.charAt(0) == 0) {
                    return null;
                }
            }
        }

        return restFormula;
    }

    public void setValue(int type, String s) {
        paused = false;
        if (this.type == Cell.URL) {
            updaterThread.run = false;
            updaterThread = null;
        }

        valueString = s;
        this.type = type;
        needRedisplay = true;
        switch (type) {
            case Cell.VALUE:
                setValue(Float.valueOf(s).floatValue());
                break;
            case Cell.LABEL:
                printString = "l" + valueString;
                break;
            case Cell.URL:
                printString = "u" + valueString;
                updaterThread = new CellUpdater(this);
                updaterThread.start();
                break;
            case Cell.FORMULA:
                parseFormula(valueString, parseRoot = new Node());
                printString = "f" + valueString;
                break;
        }
        app.recalculate();
    }

    public String getValueString() {
        return valueString;
    }

    public String getPrintString() {
        return printString;
    }

    public void select() {
        selected = true;
        paused = true;
    }

    public void deselect() {
        selected = false;
        paused = false;
        needRedisplay = true;
        app.repaint();
    }

    public void paint(Graphics g, int x, int y) {
        if (selected) {
            g.setColor(highlightColor);
        } else {
            g.setColor(bgColor);
        }
        g.fillRect(x, y, width - 1, height);
        if (valueString != null) {
            switch (type) {
                case Cell.VALUE:
                case Cell.LABEL:
                    g.setColor(fgColor);
                    break;
                case Cell.FORMULA:
                    g.setColor(Color.red);
                    break;
                case Cell.URL:
                    g.setColor(Color.blue);
                    break;
            }
            if (transientValue) {
                g.drawString("" + value, x, y + (height / 2) + 5);
            } else {
                if (valueString.length() > 14) {
                    g.drawString(valueString.substring(0, 14),
                            x, y + (height / 2) + 5);
                } else {
                    g.drawString(valueString, x, y + (height / 2) + 5);
                }
            }
        }
        needRedisplay = false;
    }
}


class Node {

    public static final int OP = 0;
    public static final int VALUE = 1;
    public static final int CELL = 2;
    int type;
    Node left;
    Node right;
    int row;
    int column;
    float value;
    char op;

    public Node() {
        left = null;
        right = null;
        value = 0;
        row = -1;
        column = -1;
        op = 0;
        type = Node.VALUE;
    }

    public Node(Node n) {
        left = n.left;
        right = n.right;
        value = n.value;
        row = n.row;
        column = n.column;
        op = n.op;
        type = n.type;
    }

    public void indent(int ind) {
        for (int i = 0; i < ind; i++) {
            System.out.print(" ");
        }
    }

    public void print(int indentLevel) {
        char l[] = new char[1];
        indent(indentLevel);
        System.out.println("NODE type=" + type);
        indent(indentLevel);
        switch (type) {
            case Node.VALUE:
                System.out.println(" value=" + value);
                break;
            case Node.CELL:
                l[0] = (char) ((int) 'A' + column);
                System.out.println(" cell=" + new String(l) + (row + 1));
                break;
            case Node.OP:
                System.out.println(" op=" + op);
                left.print(indentLevel + 3);
                right.print(indentLevel + 3);
                break;
        }
    }
}


class InputField {

    int maxchars = 50;
    int cursorPos = 0;
    Applet app;
    String sval;
    char buffer[];
    int nChars;
    int width;
    int height;
    Color bgColor;
    Color fgColor;

    public InputField(String initValue, Applet app, int width, int height,
            Color bgColor, Color fgColor) {
        this.width = width;
        this.height = height;
        this.bgColor = bgColor;
        this.fgColor = fgColor;
        this.app = app;
        buffer = new char[maxchars];
        nChars = 0;
        if (initValue != null) {
            initValue.getChars(0, initValue.length(), this.buffer, 0);
            nChars = initValue.length();
        }
        sval = initValue;
    }

    public void setText(String val) {
        int i;

        for (i = 0; i < maxchars; i++) {
            buffer[i] = 0;
        }
        if (val == null) {
            sval = "";
        } else {
            sval = val;
        }
        nChars = sval.length();
        sval.getChars(0, sval.length(), buffer, 0);
    }

    public String getValue() {
        return sval;
    }

    public void paint(Graphics g, int x, int y) {
        g.setColor(bgColor);
        g.fillRect(x, y, width, height);
        if (sval != null) {
            g.setColor(fgColor);
            g.drawString(sval, x, y + (height / 2) + 3);
        }
    }

    public void processKey(KeyEvent e) {
        char ch = e.getKeyChar();
        switch (ch) {
            case '\b': // delete
                if (nChars > 0) {
                    nChars--;
                    sval = new String(buffer, 0, nChars);
                }
                break;
            case '\n': // return
                selected();
                break;
            default:
                if (nChars < maxchars && ch >= '0') {
                    buffer[nChars++] = ch;
                    sval = new String(buffer, 0, nChars);
                }
        }
        app.repaint();
    }

    public void keyReleased(KeyEvent e) {
    }

    public void selected() {
    }
}


class SpreadSheetInput
        extends InputField {

    public SpreadSheetInput(String initValue,
            SpreadSheet app,
            int width,
            int height,
            Color bgColor,
            Color fgColor) {
        super(initValue, app, width, height, bgColor, fgColor);
    }

    @Override
    public void selected() {
        float f;
        sval = ("".equals(sval)) ? "v" : sval;
        switch (sval.charAt(0)) {
            case 'v':
                String s = sval.substring(1);
                try {
                    int i;
                    for (i = 0; i < s.length(); i++) {
                        char c = s.charAt(i);
                        if (c < '0' || c > '9') {
                            break;
                        }
                    }
                    s = s.substring(0, i);
                    f = Float.valueOf(s).floatValue();
                    ((SpreadSheet) app).setCurrentValue(f);
                } catch (NumberFormatException e) {
                    System.out.println("Not a float: '" + s + "'");
                }
                break;
            case 'l':
                ((SpreadSheet) app).setCurrentValue(Cell.LABEL,
                        sval.substring(1));
                break;
            case 'u':
                ((SpreadSheet) app).setCurrentValue(Cell.URL, sval.substring(1));
                break;
            case 'f':
                ((SpreadSheet) app).setCurrentValue(Cell.FORMULA,
                        sval.substring(1));
                break;
        }
    }
}