org.geoserver.wms.describelayer.GeoJSONDescribeLayerResponse.java Source code

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Here is the source code for org.geoserver.wms.describelayer.GeoJSONDescribeLayerResponse.java

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/* 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.geoserver.wms.describelayer;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.util.List;
import java.util.logging.Logger;

import net.sf.json.JSONException;

import org.apache.commons.io.IOUtils;
import org.geoserver.ows.Dispatcher;
import org.geoserver.ows.Request;
import org.geoserver.platform.ServiceException;
import org.geoserver.wfs.json.JSONType;
import org.geoserver.wms.DescribeLayerRequest;
import org.geoserver.wms.WMS;
import org.geotools.data.ows.LayerDescription;
import org.geotools.util.logging.Logging;

import com.thoughtworks.xstream.io.json.JsonWriter;

/**
 * A DescribeLayer response specialized in producing Json or JsonP data for a DescribeLayer request.
 * 
 * @author carlo cancellieri - GeoSolutions
 */
public class GeoJSONDescribeLayerResponse extends DescribeLayerResponse {

    /** A logger for this class. */
    protected static final Logger LOGGER = Logging.getLogger(GeoJSONDescribeLayerResponse.class);

    /**
     * The MIME type of the format this response produces, supported formats see {@link JSONType}
     */
    private final JSONType type;

    protected final WMS wms;

    /**
     * Constructor for subclasses
     */
    public GeoJSONDescribeLayerResponse(final WMS wms, final String outputFormat) {
        super(outputFormat);
        this.wms = wms;
        this.type = JSONType.getJSONType(outputFormat);
        if (type == null)
            throw new IllegalArgumentException("Not supported mime type for:" + outputFormat);
    }

    /**
     * Actually write the passed DescribeLayerModel on the OutputStream
     */
    public void write(DescribeLayerModel layers, DescribeLayerRequest request, OutputStream output)
            throws ServiceException, IOException {

        switch (type) {
        case JSON:
            OutputStreamWriter outWriter = null;
            try {
                outWriter = new OutputStreamWriter(output, wms.getGeoServer().getSettings().getCharset());

                writeJSON(outWriter, layers);
            } finally {

                if (outWriter != null) {
                    outWriter.flush();
                    IOUtils.closeQuietly(outWriter);
                }
            }
        case JSONP:
            writeJSONP(output, layers);
        }
    }

    private void writeJSONP(OutputStream out, DescribeLayerModel layers) throws IOException {

        OutputStreamWriter outWriter = null;
        try {
            outWriter = new OutputStreamWriter(out, wms.getGeoServer().getSettings().getCharset());

            outWriter.write(getCallbackFunction() + "(");

            writeJSON(outWriter, layers);
        } finally {

            if (outWriter != null) {
                outWriter.write(")");
                outWriter.flush();
                IOUtils.closeQuietly(outWriter);
            }
        }
    }

    private void writeJSON(OutputStreamWriter outWriter, DescribeLayerModel description) throws IOException {

        try {
            final JsonWriter jsonWriter = new JsonWriter(outWriter);
            final List<LayerDescription> layers = description.getLayerDescriptions();

            jsonWriter.startNode("WMS_DescribeLayerResponse", String.class);
            jsonWriter.startNode("version", String.class);
            jsonWriter.setValue(description.getVersion());
            jsonWriter.endNode();

            for (LayerDescription layer : layers) {
                jsonWriter.startNode("LayerDescription", LayerDescription.class);
                jsonWriter.startNode("name", String.class);
                jsonWriter.setValue(layer.getName());
                jsonWriter.endNode();
                jsonWriter.startNode("owsURL", URL.class);
                URL url = layer.getOwsURL();
                jsonWriter.setValue(url != null ? url.toString() : "");
                jsonWriter.endNode();
                jsonWriter.startNode("owsType", String.class);
                jsonWriter.setValue(layer.getOwsType());
                jsonWriter.endNode();
                jsonWriter.endNode();
            }
            jsonWriter.endNode();

        } catch (JSONException jsonException) {
            ServiceException serviceException = new ServiceException("Error: " + jsonException.getMessage());
            serviceException.initCause(jsonException);
            throw serviceException;
        }
    }

    private static String getCallbackFunction() {
        Request request = Dispatcher.REQUEST.get();
        if (request == null) {
            return JSONType.CALLBACK_FUNCTION;
        } else {
            return JSONType.getCallbackFunction(request.getKvp());
        }
    }

}