databasemanager.java

Java写的含有一个jdbc驱动的小型数据库数据库引擎

	} catch (IOException e) {
	    return e.getMessage();
	}
    }

    /**
     * Method declaration
     *
     *
     * @param file
     * @param text
     */
    void writeFile(String file, String text) {
	try {
	    FileWriter write = new FileWriter(file);

	    write.write(text.toCharArray());
	    write.close();
	} catch (IOException e) {
	    e.printStackTrace();
	}
    }

    /**
     * Method declaration
     *
     *
     * @param s
     * @param help
     */
    void showHelp(String s, String help) {
	txtCommand.setText(s);
	txtResult.setText(help);

	bHelp = true;

	pResult.removeAll();
	pResult.add("Center", txtResult);
	pResult.doLayout();
	txtCommand.requestFocus();
	txtCommand.setCaretPosition(s.length());
    }

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowActivated(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowDeactivated(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowClosed(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param ev
     */
    public void windowClosing(WindowEvent ev) {
	try {
	    cConn.close();
	} catch (Exception e) {}

	fMain.dispose();

	if (bMustExit) {
	    System.exit(0);
	}
    }

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowDeiconified(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowIconified(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param e
     */
    public void windowOpened(WindowEvent e) {}

    /**
     * Method declaration
     *
     *
     * @param s
     */
    void trace(String s) {
	System.out.println(s);
    }

    /**
     * Method declaration
     *
     */
    void execute() {
	String sCmd = txtCommand.getText();

	if (sCmd.startsWith("-->>>TEST<<<--")) {
	    testPerformance();

	    return;
	}

	String g[] = new String[1];

	try {
	    lTime = System.currentTimeMillis();

	    sStatement.execute(sCmd);

	    int r = sStatement.getUpdateCount();

	    if (r == -1) {
		formatResultSet(sStatement.getResultSet());
	    } else {
		g[0] = "update count";

		gResult.setHead(g);

		g[0] = "" + r;

		gResult.addRow(g);
	    }

	    lTime = System.currentTimeMillis() - lTime;

	    addToRecent(txtCommand.getText());
	} catch (SQLException e) {
	    lTime = System.currentTimeMillis() - lTime;
	    g[0] = "SQL Error";

	    gResult.setHead(g);

	    String s = e.getMessage();

	    s += " / Error Code: " + e.getErrorCode();
	    s += " / State: " + e.getSQLState();
	    g[0] = s;

	    gResult.addRow(g);
	}

	updateResult();
    }

    /**
     * Method declaration
     *
     */
    void updateResult() {
	if (iResult == 0) {

	    // in case 'help' has removed the grid
	    if (bHelp) {
		pResult.removeAll();
		pResult.add("Center", gResult);
		pResult.doLayout();

		bHelp = false;
	    }

	    gResult.update();
	    gResult.repaint();
	} else {
	    showResultInText();
	}

	txtCommand.selectAll();
	txtCommand.requestFocus();
    }

    /**
     * Method declaration
     *
     *
     * @param r
     */
    void formatResultSet(ResultSet r) {
	if (r == null) {
	    String g[] = new String[1];

	    g[0] = "Result";

	    gResult.setHead(g);

	    g[0] = "(empty)";

	    gResult.addRow(g);

	    return;
	}

	try {
	    ResultSetMetaData m = r.getMetaData();
	    int		      col = m.getColumnCount();
	    String	      h[] = new String[col];

	    for (int i = 1; i <= col; i++) {
		h[i - 1] = m.getColumnLabel(i);
	    }

	    gResult.setHead(h);

	    while (r.next()) {
		for (int i = 1; i <= col; i++) {
		    h[i - 1] = r.getString(i);

		    if (r.wasNull()) {
			h[i - 1] = "(null)";
		    }
		}

		gResult.addRow(h);
	    }

	    r.close();
	} catch (SQLException e) {}
    }

    /**
     * Method declaration
     *
     *
     * @param sql
     * @param max
     *
     * @return
     *
     * @throws SQLException
     */
    long testStatement(String sql, int max) throws SQLException {
	long start = System.currentTimeMillis();

	if (sql.indexOf('#') == -1) {
	    max = 1;
	}

	for (int i = 0; i < max; i++) {
	    String s = sql;

	    while (true) {
		int j = s.indexOf("#r#");

		if (j == -1) {
		    break;
		}

		s = s.substring(0, j) + ((int) (Math.random() * i))
		    + s.substring(j + 3);
	    }

	    while (true) {
		int j = s.indexOf('#');

		if (j == -1) {
		    break;
		}

		s = s.substring(0, j) + i + s.substring(j + 1);
	    }

	    sStatement.execute(s);
	}

	return (System.currentTimeMillis() - start);
    }

    /**
     * Method declaration
     *
     */
    void testPerformance() {
	String       all = txtCommand.getText();
	StringBuffer b = new StringBuffer();
	long	     total = 0;

	for (int i = 0; i < all.length(); i++) {
	    char c = all.charAt(i);

	    if (c != '\n') {
		b.append(c);
	    }
	}

	all = b.toString();

	String g[] = new String[4];

	g[0] = "ms";
	g[1] = "count";
	g[2] = "sql";
	g[3] = "error";

	gResult.setHead(g);

	int max = 1;

	lTime = System.currentTimeMillis() - lTime;

	while (!all.equals("")) {
	    int    i = all.indexOf(';');
	    String sql;

	    if (i != -1) {
		sql = all.substring(0, i);
		all = all.substring(i + 1);
	    } else {
		sql = all;
		all = "";
	    }

	    if (sql.startsWith("--#")) {
		max = Integer.parseInt(sql.substring(3));

		continue;
	    } else if (sql.startsWith("--")) {
		continue;
	    }

	    g[2] = sql;

	    long l = 0;

	    try {
		l = testStatement(sql, max);
		total += l;
		g[0] = "" + l;
		g[1] = "" + max;
		g[3] = "";
	    } catch (SQLException e) {
		g[0] = g[1] = "n/a";
		g[3] = e.toString();
	    }

	    gResult.addRow(g);
	    System.out.println(l + " ms : " + sql);
	}

	g[0] = "" + total;
	g[1] = "total";
	g[2] = "";

	gResult.addRow(g);

	lTime = System.currentTimeMillis() - lTime;

	updateResult();
    }

    /**
     * Method declaration
     *
     */
    void showResultInText() {
	String row[] = gResult.getHead();
	int    width = row.length;
	Vector data = gResult.getData();
	int    size[] = new int[width];

	for (int i = 0; i < width; i++) {
	    size[i] = row[i].length();
	}

	int len = data.size();

	for (int i = 0; i < len; i++) {
	    row = (String[]) data.elementAt(i);

	    for (int j = 0; j < width; j++) {
		int l = row[j].length();

		if (l > size[j]) {
		    size[j] = l;
		}
	    }
	}

	StringBuffer b = new StringBuffer();

	row = gResult.getHead();

	for (int i = 0; i < width; i++) {
	    b.append(row[i]);

	    for (int l = row[i].length(); l <= size[i]; l++) {
		b.append(' ');
	    }
	}

	b.append('\n');

	for (int i = 0; i < width; i++) {
	    for (int l = 0; l < size[i]; l++) {
		b.append('-');
	    }

	    b.append(' ');
	}

	b.append('\n');

	for (int i = 0; i < len; i++) {
	    row = (String[]) data.elementAt(i);

	    for (int j = 0; j < width; j++) {
		b.append(row[j]);

		for (int l = row[j].length(); l <= size[j]; l++) {
		    b.append(' ');
		}
	    }

	    b.append('\n');
	}

	b.append("\n" + len + " row(s) in " + lTime + " ms");
	txtResult.setText(b.toString());
    }

    /**
     * Method declaration
     *
     *
     * @param s
     */
    private void addToRecent(String s) {
	for (int i = 0; i < iMaxRecent; i++) {
	    if (s.equals(sRecent[i])) {
		return;
	    }
	}

	if (sRecent[iRecent] != null) {
	    mRecent.remove(iRecent);
	}

	sRecent[iRecent] = s;

	if (s.length() > 43) {
	    s = s.substring(0, 40) + "...";
	}

	MenuItem item = new MenuItem(s);

	item.setActionCommand("#" + iRecent);
	item.addActionListener(this);
	mRecent.insert(item, iRecent);

	iRecent = (iRecent + 1) % iMaxRecent;
    }

    /**
     * Method declaration
     *
     */
    private void initGUI() {
	Panel pQuery = new Panel();
	Panel pCommand = new Panel();

	pResult = new Panel();

	pQuery.setLayout(new BorderLayout());
	pCommand.setLayout(new BorderLayout());
	pResult.setLayout(new BorderLayout());

	Font fFont = new Font("Dialog", Font.PLAIN, 12);

	txtCommand = new TextArea(5, 40);

	txtCommand.addKeyListener(this);

	txtResult = new TextArea(20, 40);

	txtCommand.setFont(fFont);
	txtResult.setFont(new Font("Courier", Font.PLAIN, 12));

	butExecute = new Button("Execute");

	butExecute.addActionListener(this);
	pCommand.add("East", butExecute);
	pCommand.add("Center", txtCommand);

	gResult = new Grid();

	setLayout(new BorderLayout());
	pResult.add("Center", gResult);
	pQuery.add("North", pCommand);
	pQuery.add("Center", pResult);
	fMain.add("Center", pQuery);

	tTree = new Tree();

	tTree.setMinimumSize(new Dimension(200, 100));
	gResult.setMinimumSize(new Dimension(200, 300));
	fMain.add("West", tTree);
	doLayout();
	fMain.pack();
    }

    /**
     * Method declaration
     *
     */
    private void refreshTree() {
	tTree.removeAll();

	try {
	    int color_table = Color.yellow.getRGB();
	    int color_column = Color.orange.getRGB();
	    int color_index = Color.red.getRGB();

	    tTree.addRow("", dMeta.getURL(), "-", 0);

	    String    usertables[] = {
		"TABLE"
	    };
	    ResultSet result = dMeta.getTables(null, null, null, usertables);
	    Vector    tables = new Vector();

	    while (result.next()) {
		tables.addElement(result.getString(3));
	    }

	    result.close();

	    for (int i = 0; i < tables.size(); i++) {
		String name = (String) tables.elementAt(i);
		String key = "tab-" + name + "-";

		tTree.addRow(key, name, "+", color_table);

		ResultSet col = dMeta.getColumns(null, null, name, null);

		while (col.next()) {
		    String c = col.getString(4);
		    String k1 = key + "col-" + c + "-";

		    tTree.addRow(k1, c, "+", color_column);

		    String type = col.getString(6);

		    tTree.addRow(k1 + "t", "Type: " + type);

		    boolean nullable = col.getInt(11)
				       != DatabaseMetaData.columnNoNulls;

		    tTree.addRow(k1 + "n", "Nullable: " + nullable);
		}

		col.close();
		tTree.addRow(key + "ind", "Indices", "+", 0);

		ResultSet ind = dMeta.getIndexInfo(null, null, name, false,
						   false);
		String    oldiname = null;

		while (ind.next()) {
		    boolean nonunique = ind.getBoolean(4);
		    String  iname = ind.getString(6);
		    String  k2 = key + "ind-" + iname + "-";

		    if ((oldiname == null ||!oldiname.equals(iname))) {
			tTree.addRow(k2, iname, "+", color_index);
			tTree.addRow(k2 + "u", "Unique: " + !nonunique);

			oldiname = iname;
		    }

		    String c = ind.getString(9);

		    tTree.addRow(k2 + "c-" + c + "-", c);
		}

		ind.close();
	    }

	    tTree.addRow("p", "Properties", "+", 0);
	    tTree.addRow("pu", "User: " + dMeta.getUserName());
	    tTree.addRow("pr", "ReadOnly: " + cConn.isReadOnly());
	    tTree.addRow("pa", "AutoCommit: " + cConn.getAutoCommit());
	    tTree.addRow("pd", "Driver: " + dMeta.getDriverName());
	    tTree.addRow("pp", "Product: " + dMeta.getDatabaseProductName());
	    tTree.addRow("pv",
			 "Version: " + dMeta.getDatabaseProductVersion());
	} catch (SQLException e) {
	    tTree.addRow("", "Error getting metadata:", "-", 0);
	    tTree.addRow("-", e.getMessage());
	    tTree.addRow("-", e.getSQLState());
	}

	tTree.update();
    }

}