bufferedshapelayer.java

来自「OpenMap是一个基于JavaBeansTM的开发工具包。利用OpenMap你」· Java 代码 · 共 167 行

// **********************************************************************
// 
// <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/layer/shape/BufferedShapeLayer.java,v $
// $RCSfile: BufferedShapeLayer.java,v $
// $Revision: 1.4.2.4 $
// $Date: 2007/06/21 21:41:41 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.layer.shape;

import java.awt.event.ActionEvent;
import java.io.IOException;
import java.util.Iterator;

import com.bbn.openmap.LatLonPoint;
import com.bbn.openmap.io.FormatException;
import com.bbn.openmap.layer.shape.SpatialIndex.Entry;
import com.bbn.openmap.omGraphics.OMGraphic;
import com.bbn.openmap.omGraphics.OMGraphicList;
import com.bbn.openmap.proj.ProjMath;
import com.bbn.openmap.proj.Projection;
import com.bbn.openmap.util.Debug;

/**
 * An OpenMap Layer that displays shape files. This loads the data up front and
 * then just reprojects/repaints when needed. Note that the ESRIRecords have
 * been updated so that the OMGraphics that get created from them are loaded
 * with an Integer object that notes the number of the record as it was read
 * from the .shp file. This lets you align the object with the correct attribute
 * data in the .dbf file.
 */
public class BufferedShapeLayer extends ShapeLayer {

    protected OMGraphicList bufferedList = null;

    /**
     * Initializes an empty shape layer.
     */
    public BufferedShapeLayer() {
        super();
        setProjectionChangePolicy(new com.bbn.openmap.layer.policy.StandardPCPolicy(this));
    }

    /**
     * Get the graphics for the entire planet.
     */
    protected OMGraphicList getWholePlanet() throws IOException,
            FormatException {
        return spatialIndex.getOMGraphics(-180,
                -90,
                180,
                90,
                (OMGraphicList) null,
                drawingAttributes,
                (Projection) null,
                coordTransform);
    }

    /**
     * This overridden method checks to see if the buffered OMGraphicList is
     * created, and then returns a subset of OMGraphics that are actually on the
     * map. If the buffered OMGraphicList hasn't been created yet, it gets
     * created here.
     */
    public synchronized OMGraphicList prepare() {

        OMGraphicList list = getList();

        if (list != null) {
            list.clear();
        } else {
            list = new OMGraphicList();
        }

        if (spatialIndex == null)
            return list;

        try {
            if (bufferedList == null) {
                bufferedList = getWholePlanet();
            }
        } catch (FormatException fe) {
            Debug.error(fe.getMessage());
            return list;
        } catch (IOException ioe) {
            Debug.error(ioe.getMessage());
            return list;
        }

        // grab local
        Projection proj = getProjection();

        LatLonPoint ul = proj.getUpperLeft();
        LatLonPoint lr = proj.getLowerRight();
        float ulLat = ul.getLatitude();
        float ulLon = ul.getLongitude();
        float lrLat = lr.getLatitude();
        float lrLon = lr.getLongitude();

        // check for dateline anomaly on the screen. we check for
        // ulLon >= lrLon, but we need to be careful of the check for
        // equality because of floating point arguments...
        if (ProjMath.isCrossingDateline(ulLon, lrLon, proj.getScale())) {
            if (Debug.debugging("shape")) {
                Debug.output("ShapeLayer.computeGraphics(): Dateline is on screen");
            }

            double ymin = (double) Math.min(ulLat, lrLat);
            double ymax = (double) Math.max(ulLat, lrLat);

            checkSpatialIndexEntries(ulLon, ymin, 180.0d, ymax, list, proj);
            checkSpatialIndexEntries(-180.0d, ymin, lrLon, ymax, list, proj);

        } else {

            double xmin = (double) Math.min(ulLon, lrLon);
            double xmax = (double) Math.max(ulLon, lrLon);
            double ymin = (double) Math.min(ulLat, lrLat);
            double ymax = (double) Math.max(ulLat, lrLat);

            checkSpatialIndexEntries(xmin, ymin, xmax, ymax, list, proj);
        }

        return list;
    }

    protected void checkSpatialIndexEntries(double xmin, double ymin,
                                            double xmax, double ymax,
                                            OMGraphicList retList,
                                            Projection proj) {
        // There should be the same number of objects in both iterators.
        Iterator entryIt = spatialIndex.entries.iterator();
        Iterator omgIt = bufferedList.iterator();
        while (entryIt.hasNext() && omgIt.hasNext()) {
            Entry entry = (Entry) entryIt.next();
            OMGraphic omg = (OMGraphic) omgIt.next();
            if (entry.intersects(xmin, ymin, xmax, ymax)) {
                drawingAttributes.setTo(omg);
                omg.generate(proj);
                retList.add(omg);
            }
        }
    }

    public void actionPerformed(ActionEvent e) {
        String cmd = e.getActionCommand();
        if (cmd == RedrawCmd) {
            setList(null);
        }
        super.actionPerformed(e);
    }

}