adfhorizonlookup.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.web.projection.horizon;

import com.esri.adf.web.data.geometry.WebExtent;
import com.esri.adf.web.data.geometry.WebPolygon;
import com.esri.adf.web.data.geometry.WebRing;
import com.esri.adf.web.data.geometry.WebSpatialReference;

import org.apache.log4j.Logger;


public class ADFHorizonLookup implements IHorizonLookup {
    private static final Logger _logger = Logger.getLogger(ADFHorizonLookup.class);

    public WebExtent lookup(int spatialReferenceId) {
        WebExtent horizon = null;
        WebSpatialReference spr = null;
        WebPolygon polyHorizon = null;
        double minx = 180D;
        double miny = 90D;
        double maxx = -180D;
        double maxy = -90D;

        try {
            _logger.debug("Creating WebSpatialReference for ID: " +
                spatialReferenceId);

            spr = WebSpatialReference.getWebSpatialReference(spatialReferenceId);

            if (spr == null) {
                _logger.warn(
                    "Unable to create WebSpatialReference for given ID: " +
                    spatialReferenceId);

                return horizon;
            }

            polyHorizon = spr.getHorizon(false);

            for (WebRing ring : polyHorizon.getRings()) {
                for (double x : ring.getXs()) {
                    if (x < minx) {
                        minx = x;
                    } else if (x > maxx) {
                        maxx = x;
                    }
                }

                for (double y : ring.getYs()) {
                    if (y < miny) {
                        miny = y;
                    } else if (y > maxy) {
                        maxy = y;
                    }
                }
            }

            horizon = new WebExtent(minx, miny, maxx, maxy, spr);

            _logger.debug(
                "Successfully retrieved horizon for Spatial Reference: " +
                spr.getId());

            return horizon;
        } catch (Exception ex) {
            _logger.warn(
                "An Exception has occurred retrieving horizon for Spatial Reference: " +
                spatialReferenceId);
            _logger.error(
                "An Exception has occurred retrieving horizon for Spatial Reference: " +
                spatialReferenceId, ex);

            return null;
        }
    }
}