timeslidersupport.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

// **********************************************************************
// 
// <copyright>
// 
//  BBN Technologies
//  10 Moulton Street
//  Cambridge, MA 02138
//  [phone]
// 
//  Copyright (C) BBNT Solutions LLC. All rights reserved.
// 
// </copyright>
// **********************************************************************
// 
// $Source:
// /cvs/distapps/openmap/src/openmap/com/bbn/openmap/gui/time/TimeSliderSupport.java,v
// $
// $RCSfile: TimeSliderSupport.java,v $
// $Revision: 1.4.2.3 $
// $Date: 2004/10/14 18:26:56 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.gui.time;

import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import com.bbn.openmap.util.Debug;

public class TimeSliderSupport implements TimeConstants, ChangeListener {

    protected JSlider timeSlider;
    protected RealTimeHandler rtHandler;
    protected long startTime;
    protected long endTime;

    public TimeSliderSupport(JSlider slider, RealTimeHandler rth,
            long startingTime, long endingTime) {
        timeSlider = slider;
        rtHandler = rth;
        startTime = startingTime;
        endTime = endingTime;

        if (Debug.debugging("timedetail")) {
            Debug.output("TimeSliderSupport: initialized to:" + startTime
                    + ", " + endTime);
        }

        timeSlider.addChangeListener(this);
    }

    /**
     * Updates the position of the slider to a place reflective to the
     * startTime and endTime of this support object. Only moves the
     * slider marker if the difference is greater than one.
     */
    public void update(long time) {
        if (timeSlider != null) {
            int minimum = timeSlider.getMinimum();
            int maximum = timeSlider.getMaximum();
            if (time <= startTime) {
                timeSlider.setValue(minimum);
            } else if (time >= endTime) {
                timeSlider.setValue(maximum);
            } else {
                double diff = endTime - startTime;
                if (diff == 0) {
                    diff = 1;
                }
                double val = minimum;
                if (diff != 0) {
                    val = ((double) (time - startTime) / diff)
                            * (maximum - minimum);
                }

                if (Math.abs(val - timeSlider.getValue()) > 1) {
                    if (Debug.debugging("timedetail")) {
                        Debug.output("TimeSliderSupport: Setting time slider to : "
                                + val);
                    }
                    timeSlider.setValue((int) val);
                }
            }
        }
    }

    /**
     * ChangeListener method, sets the time on the RealTimeHandler
     * based on the current setting on the slider.
     */
    public void stateChanged(ChangeEvent ce) {
        if (ce.getSource() == timeSlider) {
            rtHandler.setTime(getTime());
        }
    }

    /**
     * Get the time reflected by the current setting of the slider.
     * Assumes that the JSlider has been set in this TimeSliderSupport
     * object.
     */
    protected long getTime() {
        int maximum = timeSlider.getMaximum();
        int minimum = timeSlider.getMinimum();
        int value = timeSlider.getValue();

        try {
            return (startTime + (long) ((endTime - startTime) * value / (maximum - minimum)));
        } catch (ArithmeticException ae) {
            Debug.error("TimeSliderSupport.getTime(): " + ae.getMessage());
            if (Debug.debugging("timedetail")) {
                ae.printStackTrace();
            }
            return startTime;
        }
    }

    public void setTimeSlider(JSlider jslider) {
        timeSlider = jslider;
    }

    public JSlider setTimeSlider() {
        return timeSlider;
    }

    public void setHandler(RealTimeHandler rth) {
        rtHandler = rth;
    }

    public RealTimeHandler getHandler() {
        return rtHandler;
    }

    public void setStartTime(long time) {
        startTime = time;
    }

    public long getStartTime() {
        return startTime;
    }

    public void setEndTime(long time) {
        endTime = time;
    }

    public long getEndTime() {
        return endTime;
    }
}