abstractservice.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.servlets;

import org.geoserver.ows.ServiceStrategy;
import org.geoserver.ows.util.XmlCharsetDetector;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.web.context.WebApplicationContext;
import org.vfny.geoserver.ExceptionHandler;
import org.vfny.geoserver.Request;
import org.vfny.geoserver.Response;
import org.vfny.geoserver.ServiceException;
import org.vfny.geoserver.global.Data;
import org.vfny.geoserver.global.GeoServer;
import org.vfny.geoserver.global.Service;
import org.vfny.geoserver.util.PartialBufferedOutputStream2;
import org.vfny.geoserver.util.requests.readers.KvpRequestReader;
import org.vfny.geoserver.util.requests.readers.XmlRequestReader;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Reader;
import java.net.SocketException;
import java.nio.charset.Charset;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * Represents a service that all others extend from.  Subclasses should provide
 * response and exception handlers as appropriate.
 *
 * <p>
 * It is <b>really</b> important to adhere to the following workflow:
 *
 * <ol>
 * <li>
 * get a Request reader
 * </li>
 * <li>
 * ask the Request Reader for the Request object
 * </li>
 * <li>
 * Provide the resulting Request with the ServletRequest that generated it
 * </li>
 * <li>
 * get the appropiate ResponseHandler
 * </li>
 * <li>
 * ask it to execute the Request
 * </li>
 * <li>
 * set the response content type
 * </li>
 * <li>
 * write to the http response's output stream
 * </li>
 * <li>
 * pending - call Response cleanup
 * </li>
 * </ol>
 * </p>
 *
 * <p>
 * If anything goes wrong a ServiceException can be thrown and will be written
 * to the output stream instead.
 * </p>
 *
 * <p>
 * This is because we have to be sure that no exception have been produced
 * before setting the response's content type, so we can set the exception
 * specific content type; and that Response.getContentType is called AFTER
 * Response.execute, since the MIME type can depend on any request parameter
 * or another kind of desission making during the execute process. (i.e.
 * FORMAT in WMS GetMap)
 * </p>
 *
 * <p>
 * TODO: We need to call Response.abort() if anything goes wrong to allow the
 * Response a chance to cleanup after itself.
 * </p>
 *
 * @author Gabriel Rold?n
 * @author Chris Holmes
 * @author Jody Garnett, Refractions Research
 * @version $Id: AbstractService.java 7746 2007-11-13 15:38:35Z aaime $
 */
public abstract class AbstractService extends HttpServlet implements ApplicationContextAware {
    /** Class logger */
    protected static Logger LOGGER = org.geotools.util.logging.Logging.getLogger("org.vfny.geoserver.servlets");

    /**
     * Servivce group (maps to 'SERVICE' parameter in OGC service urls)
     */
    String service;

    /**
     * Request type (maps to 'REQUEST' parameter in OGC service urls)
     */
    String request;

    /**
     * Application context used to look up "Services"
     */
    WebApplicationContext context;

    /**
     * Reference to the global geoserver instnace.
     */
    GeoServer geoServer;

    /**
     * Reference to the catalog.
     */
    Data catalog;

    /**
     * Id of the service strategy to use.
     */
    String serviceStrategy;

    /**
     * buffer size to use when PARTIAL-BUFFER is being used
     */
    int partialBufferSize;

    /**
     * Cached service strategy object
     */

    //    ServiceStrategy strategy;

    /**
     * Reference to the service
     */
    Service serviceRef;
    private String kvpString;

    //    /** DOCUMENT ME!  */
    //    protected HttpServletRequest curRequest;

    /**
     * Constructor for abstract service.
     *
     * @param service The service group the service falls into (WFS,WMS,...)
     * @param request The service being requested (GetCapabilities, GetMap, ...)
     * @param serviceRef The global service this "servlet" falls into
     */
    public AbstractService(String service, String request, Service serviceRef) {
        this.service = service;
        this.request = request;
        this.serviceRef = serviceRef;
    }

    /**
     * @return Returns the "service group" that this service falls into.
     */
    public String getService() {
        return service;
    }

    /**
     * @return Returns the "request" this service maps to.
     */
    public String getRequest() {
        return request;
    }

    /**
     * Sets a refeference to the global service instance.
     */
    public void setServiceRef(Service serviceRef) {
        this.serviceRef = serviceRef;
    }

    /**
     * @return The reference to the global service instance.
     */
    public Service getServiceRef() {
        return serviceRef;
    }

    /**
     * Sets the application context.
     * <p>
     * Used to process the {@link Service} extension point.
     * </p>
     */
    public void setApplicationContext(ApplicationContext context)
        throws BeansException {
        this.context = (WebApplicationContext) context;
    }

    /**
     * @return The application context.
     */
    public WebApplicationContext getApplicationContext() {
        return context;
    }

    /**
     * Sets the reference to the global geoserver instance.
     */
    public void setGeoServer(GeoServer geoServer) {
        this.geoServer = geoServer;
    }

    /**
     * @return the reference to the global geoserver instance.
     */
    public GeoServer getGeoServer() {
        return geoServer;
    }

    /**
     * @return The reference to the global catalog instance.
     */
    public Data getCatalog() {
        return catalog;
    }

    /**
     * Sets the reference to the global catalog instance.
     *
     */
    public void setCatalog(Data catalog) {
        this.catalog = catalog;
    }

    /**
     * @return The id used to identify the service strategy to be used.
     * @see ServiceStrategy#getId()
     */
    public String getServiceStrategy() {
        return serviceStrategy;
    }

    /**
     * Sets the id used to identify the service strategy to be used.
     */
    public void setServiceStrategy(String serviceStrategy) {
        this.serviceStrategy = serviceStrategy;
    }

    /**
     * Determines if the service is enabled.
     * <p>
     * Subclass should override this method if the service can be turned on/off.
     * This implementation returns <code>true</code>
     * </p>
     */
    protected boolean isServiceEnabled(HttpServletRequest req) {
        return true;
    }

    /**
     * Override and use spring set servlet context.
     */
    public ServletContext getServletContext() {
        //override and use spring 
        return ((WebApplicationContext) context).getServletContext();
    }

    /**
     * DOCUMENT ME!
     *
     * @param request DOCUMENT ME!
     * @param response DOCUMENT ME!
     *
     * @throws ServletException DOCUMENT ME!
     * @throws IOException DOCUMENT ME!
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        // implements the main request/response logic
        // this.curRequest = request;
        Request serviceRequest = null;

        if (!isServiceEnabled(request)) {
            sendDisabledServiceError(response);

            return;
        }

        try {
            Map requestParams = new HashMap();
            String qString = ((this.kvpString != null) ? this.kvpString : request.getQueryString());
            LOGGER.fine("reading request: " + qString);

            if (this.kvpString != null) {
                requestParams = KvpRequestReader.parseKvpSet(qString);
            } else {
                String paramName;
                String paramValue;

                for (Enumeration pnames = request.getParameterNames(); pnames.hasMoreElements();) {
                    paramName = (String) pnames.nextElement();
                    paramValue = request.getParameter(paramName);
                    requestParams.put(paramName.toUpperCase(), paramValue);
                }
            }

            KvpRequestReader requestReader = getKvpReader(requestParams);

            serviceRequest = requestReader.getRequest(request);
            LOGGER.finer("serviceRequest provided with HttpServletRequest: " + request);

            //serviceRequest.setHttpServletRequest(request);
        } catch (ServiceException se) {
            sendError(request, response, se);

            return;
        } catch (Throwable e) {
            sendError(request, response, e);

            return;
        } finally {
            this.kvpString = null;
        }