graph.java

java B++树 一个很好的算法来实现这些问题 推荐！

package cq_result_trans.test;

/*
 * @(#)Graph.java	1.16 04/07/26
 */

import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;


class Node {
    double x;
    double y;

    double dx;
    double dy;

    boolean fixed;

    String lbl;
}


class Edge {
    int from;
    int to;

    double len;
}


class GraphPanel extends Panel
    implements Runnable, MouseListener, MouseMotionListener {
    Graph graph;
    int nnodes;
    Node nodes[] = new Node[100];

    int nedges;
    Edge edges[] = new Edge[200];

    Thread relaxer;
    boolean stress;
    boolean random;

    int numMouseButtonsDown = 0;

    GraphPanel(Graph graph) {
        this.graph = graph;
        addMouseListener(this);
    }

    int findNode(String lbl) {
        for (int i = 0 ; i < nnodes ; i++) {
            if (nodes[i].lbl.equals(lbl)) {
                return i;
            }
        }
        return addNode(lbl);
    }
    int addNode(String lbl) {
        Node n = new Node();
        n.x = 10 + 380*Math.random();
        n.y = 10 + 380*Math.random();
        n.lbl = lbl;
        nodes[nnodes] = n;
        return nnodes++;
    }
    void addEdge(String from, String to, int len) {
        Edge e = new Edge();
        e.from = findNode(from);
        e.to = findNode(to);
        e.len = len;
        edges[nedges++] = e;
    }

    public void run() {
        //Thread me = Thread.currentThread();
        //while (relaxer == me)
        while(true){
            relax();
            if (random && (Math.random() < 0.03)) {
                Node n = nodes[(int)(Math.random() * nnodes)];
                if (!n.fixed) {
                    n.x += 100*Math.random() - 50;
                    n.y += 100*Math.random() - 50;
                }
                graph.play(graph.getCodeBase(), "audio/drip.au");
            }
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                break;
            }
        }
    }

    synchronized void relax() {
        for (int i = 0 ; i < nedges ; i++) {
            Edge e = edges[i];
            double vx = nodes[e.to].x - nodes[e.from].x;
            double vy = nodes[e.to].y - nodes[e.from].y;
            double len = Math.sqrt(vx * vx + vy * vy);
            len = (len == 0) ? .0001 : len;
            double f = (edges[i].len - len) / (len * 3);
            double dx = f * vx;
            double dy = f * vy;

            nodes[e.to].dx += dx;
            nodes[e.to].dy += dy;
            nodes[e.from].dx += -dx;
            nodes[e.from].dy += -dy;
        }

        for (int i = 0 ; i < nnodes ; i++) {
            Node n1 = nodes[i];
            double dx = 0;
            double dy = 0;

            for (int j = 0 ; j < nnodes ; j++) {
                if (i == j) {
                    continue;
                }
                Node n2 = nodes[j];
                double vx = n1.x - n2.x;
                double vy = n1.y - n2.y;
                double len = vx * vx + vy * vy;
                if (len == 0) {
                    dx += Math.random();
                    dy += Math.random();
                } else if (len < 100*100) {
                    dx += vx / len;
                    dy += vy / len;
                }
            }
            double dlen = dx * dx + dy * dy;
            if (dlen > 0) {
                dlen = Math.sqrt(dlen) / 2;
                n1.dx += dx / dlen;
                n1.dy += dy / dlen;
            }
        }

        Dimension d = getSize();
        for (int i = 0 ; i < nnodes ; i++) {
            Node n = nodes[i];
            if (!n.fixed) {
                n.x += Math.max(-5, Math.min(5, n.dx));
                n.y += Math.max(-5, Math.min(5, n.dy));
            }
            if (n.x < 0) {
                n.x = 0;
            } else if (n.x > d.width) {
                n.x = d.width;
            }
            if (n.y < 0) {
                n.y = 0;
            } else if (n.y > d.height) {
                n.y = d.height;
            }
            n.dx /= 2;
            n.dy /= 2;
        }
        repaint();
    }

    Node pick;
    boolean pickfixed;
    Image offscreen;
    Dimension offscreensize;
    Graphics offgraphics;

    final Color fixedColor = Color.red;
    final Color selectColor = Color.pink;
    final Color edgeColor = Color.black;
    final Color nodeColor = new Color(250, 220, 100);
    final Color stressColor = Color.darkGray;
    final Color arcColor1 = Color.black;
    final Color arcColor2 = Color.pink;
    final Color arcColor3 = Color.red;

    public void paintNode(Graphics g, Node n, FontMetrics fm) {
        int x = (int)n.x;
        int y = (int)n.y;
        g.setColor((n == pick) ? selectColor : (n.fixed ? fixedColor : nodeColor));
        int w = fm.stringWidth(n.lbl) + 10;
        int h = fm.getHeight() + 4;
        g.fillRect(x - w/2, y - h / 2, w, h);
        g.setColor(Color.black);
        g.drawRect(x - w/2, y - h / 2, w-1, h-1);
        g.drawString(n.lbl, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());
    }

    public synchronized void update(Graphics g) {
        Dimension d = getSize();
        if ((offscreen == null) || (d.width != offscreensize.width) || (d.height != offscreensize.height)) {
            offscreen = createImage(d.width, d.height);
            offscreensize = d;
            if (offgraphics != null) {
                offgraphics.dispose();
            }
            offgraphics = offscreen.getGraphics();
            offgraphics.setFont(getFont());
        }

        offgraphics.setColor(getBackground());
        offgraphics.fillRect(0, 0, d.width, d.height);
        for (int i = 0 ; i < nedges ; i++) {
            Edge e = edges[i];
            int x1 = (int)nodes[e.from].x;
            int y1 = (int)nodes[e.from].y;
            int x2 = (int)nodes[e.to].x;
            int y2 = (int)nodes[e.to].y;
            int len = (int)Math.abs(Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)) - e.len);
            offgraphics.setColor((len < 10) ? arcColor1 : (len < 20 ? arcColor2 : arcColor3)) ;
            offgraphics.drawLine(x1, y1, x2, y2);
            if (stress) {
                String lbl = String.valueOf(len);
                offgraphics.setColor(stressColor);
                offgraphics.drawString(lbl, x1 + (x2-x1)/2, y1 + (y2-y1)/2);
                offgraphics.setColor(edgeColor);
            }
        }

        FontMetrics fm = offgraphics.getFontMetrics();
        for (int i = 0 ; i < nnodes ; i++) {
            paintNode(offgraphics, nodes[i], fm);
        }
        g.drawImage(offscreen, 0, 0, null);
    }

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

    public void mousePressed(MouseEvent e) {
        numMouseButtonsDown++;
        addMouseMotionListener(this);
        double bestdist = Double.MAX_VALUE;

        int x = e.getX();
        int y = e.getY();
        for (int i = 0 ; i < nnodes ; i++) {
            Node n = nodes[i];
            double dist = (n.x - x) * (n.x - x) + (n.y - y) * (n.y - y);
            if (dist < bestdist) {
                pick = n;
                bestdist = dist;
            }
        }
        pickfixed = pick.fixed;
        pick.fixed = true;
        pick.x = x;
        pick.y = y;

        repaint();
        e.consume();
    }

    public void mouseReleased(MouseEvent e) {
        numMouseButtonsDown--;
        removeMouseMotionListener(this);

        pick.fixed = pickfixed;
        pick.x = e.getX();
        pick.y = e.getY();
        if (numMouseButtonsDown == 0) {
            pick = null;
        }

        repaint();
        e.consume();
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }

    public void mouseDragged(MouseEvent e) {
        pick.x = e.getX();
        pick.y = e.getY();
        repaint();
        e.consume();
    }

    public void mouseMoved(MouseEvent e) {
    }

    public void start() {
        relaxer = new Thread(this);
        relaxer.start();
    }

    public void stop() {
        relaxer = null;
    }

}


public class Graph extends Applet implements ActionListener, ItemListener {

    GraphPanel panel;
    Panel controlPanel;

    Button scramble = new Button("Scramble");
    Button shake = new Button("Shake");
    Checkbox stress = new Checkbox("Stress");
    Checkbox random = new Checkbox("Random");

    public void init() {
        setLayout(new BorderLayout());

        panel = new GraphPanel(this);
        add("Center", panel);
        controlPanel = new Panel();
        add("South", controlPanel);

        controlPanel.add(scramble); scramble.addActionListener(this);
        controlPanel.add(shake); shake.addActionListener(this);
        controlPanel.add(stress); stress.addItemListener(this);
        controlPanel.add(random); random.addItemListener(this);

        String edges = getParameter("edges");
        for (StringTokenizer t = new StringTokenizer(edges, ",") ; t.hasMoreTokens() ; ) {
            String str = t.nextToken();
            int i = str.indexOf('-');
            if (i > 0) {
                int len = 50;
                int j = str.indexOf('/');
                if (j > 0) {
                    len = Integer.valueOf(str.substring(j+1)).intValue();
                    str = str.substring(0, j);
                }
                panel.addEdge(str.substring(0,i), str.substring(i+1), len);
            }
        }
        Dimension d = getSize();
        String center = getParameter("center");
        if (center != null){
            Node n = panel.nodes[panel.findNode(center)];
            n.x = d.width / 2;
            n.y = d.height / 2;
            n.fixed = true;
        }
    }

    public void destroy() {
        remove(panel);
        remove(controlPanel);
    }

    public void start() {
        panel.start();
    }

    public void stop() {
        panel.stop();
    }

    public void actionPerformed(ActionEvent e) {
        Object src = e.getSource();

        if (src == scramble) {
            play(getCodeBase(), "audio/computer.au");
            Dimension d = getSize();
            for (int i = 0 ; i < panel.nnodes ; i++) {
                Node n = panel.nodes[i];
                if (!n.fixed) {
                    n.x = 10 + (d.width-20)*Math.random();
                    n.y = 10 + (d.height-20)*Math.random();
                }
            }
            return;
        }

        if (src == shake) {
            play(getCodeBase(), "audio/gong.au");
            Dimension d = getSize();
            for (int i = 0 ; i < panel.nnodes ; i++) {
                Node n = panel.nodes[i];
                if (!n.fixed) {
                    n.x += 80*Math.random() - 40;
                    n.y += 80*Math.random() - 40;
                }
            }
        }

    }

    public void itemStateChanged(ItemEvent e) {
        Object src = e.getSource();
        boolean on = e.getStateChange() == ItemEvent.SELECTED;
        if (src == stress) panel.stress = on;
        else if (src == random) panel.random = on;
    }

    public String getAppletInfo() {
        return "Title: GraphLayout \nAuthor: <unknown>";
    }

    public String[][] getParameterInfo() {
        String[][] info = {
            {"edges", "delimited string", "A comma-delimited list of all the edges.  It takes the form of 'C-N1,C-N2,C-N3,C-NX,N1-N2/M12,N2-N3/M23,N3-NX/M3X,...' where C is the name of center node (see 'center' parameter) and NX is a node attached to the center node.  For the edges connecting nodes to each other (and not to the center node) you may (optionally) specify a length MXY separated from the edge name by a forward slash."},
            {"center", "string", "The name of the center node."}
        };
        return info;
    }

}