asccoverageresponsedelegate.java

电子地图服务器,搭建自己的地图服务

/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org.  All rights reserved.
 * This code is licensed under the GPL 2.0 license, availible at the root
 * application directory.
 */
package org.vfny.geoserver.wcs.responses.coverage;

import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.gce.arcgrid.ArcGridWriter;
import org.opengis.coverage.grid.GridCoverageWriter;
import org.opengis.parameter.ParameterValueGroup;
import org.vfny.geoserver.ServiceException;
import org.vfny.geoserver.global.GeoServer;
import org.vfny.geoserver.wcs.WcsException;
import org.vfny.geoserver.wcs.responses.CoverageResponseDelegate;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;


/**
 * DOCUMENT ME!
 *
 * @author $Author: Alessio Fabiani ([e-mail]) $ (last
 *         modification)
 * @author $Author: Simone Giannecchini ([e-mail]) $ (last
 *         modification)
 */
public class AscCoverageResponseDelegate implements CoverageResponseDelegate {
    /**
     *
     * @uml.property name="sourceCoverage"
     * @uml.associationEnd multiplicity="(0 1)"
     */
    private GridCoverage2D sourceCoverage;
    private boolean compressOutput = false;

    public AscCoverageResponseDelegate() {
    }

    public boolean canProduce(String outputFormat) {
        return "ArcGrid".equalsIgnoreCase(outputFormat)
        || "ArcGrid-GZIP".equalsIgnoreCase(outputFormat);
    }

    public void prepare(String outputFormat, GridCoverage2D coverage)
        throws IOException {
        this.compressOutput = "ArcGrid-GZIP".equalsIgnoreCase(outputFormat);
        this.sourceCoverage = coverage;
    }

    public String getContentType(GeoServer gs) {
        // return gs.getMimeType();
        return compressOutput ? "application/x-gzip" : "text/plain";
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public String getContentEncoding() {
        // return compressOutput ? "gzip" : null;
        return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public String getContentDisposition() {
        return compressOutput ? ("attachment;filename=" + this.sourceCoverage.getName() + ".asc.gz")
                              : null;
    }

    public void encode(OutputStream output) throws ServiceException, IOException {
        if (sourceCoverage == null) {
            throw new IllegalStateException(new StringBuffer(
                    "It seems prepare() has not been called").append(" or has not succeed")
                                                                                                      .toString());
        }

        GZIPOutputStream gzipOut = null;

        if (compressOutput) {
            gzipOut = new GZIPOutputStream(output);
            output = gzipOut;
        }

        try {
            final GridCoverageWriter writer = new ArcGridWriter(output);
            final ParameterValueGroup params = writer.getFormat().getWriteParameters();
            //params.parameter("Compressed").setValue(compressOutput);
            writer.write(sourceCoverage, null);

            if (gzipOut != null) {
                gzipOut.finish();
                gzipOut.flush();
            }

            // freeing everything
            writer.dispose();
            this.sourceCoverage.dispose();
            this.sourceCoverage = null;
        } catch (Exception e) {
            throw new WcsException(new StringBuffer("Problems Rendering Image").append(
                    e.getMessage()).toString(), e);
        }
    }
}