view flys-client/src/main/java/de/intevation/flys/client/server/WQInfoServiceImpl.java @ 3497:88feb3347aa5

Implement a ProxyServlet Implement a ProxyServlet to be able to restrict the access to the mapserver too. All queries to the provided map services should go throught this new ProxyServlet. Currently the ProxyServlet can only handle HTTP GET requests. flys-client/trunk@5221 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Bjoern Ricks <bjoern.ricks@intevation.de>
date Thu, 16 Aug 2012 14:42:36 +0000
parents bc06a671ef60
children e70ff0a600a3
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package de.intevation.flys.client.server;

import java.util.ArrayList;
import java.util.List;

import javax.xml.xpath.XPathConstants;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.apache.log4j.Logger;

import com.google.gwt.user.server.rpc.RemoteServiceServlet;

import de.intevation.artifacts.common.ArtifactNamespaceContext;
import de.intevation.artifacts.common.utils.XMLUtils;

import de.intevation.artifacts.httpclient.exceptions.ConnectionException;
import de.intevation.artifacts.httpclient.http.HttpClient;
import de.intevation.artifacts.httpclient.http.HttpClientImpl;

import de.intevation.flys.client.shared.exceptions.ServerException;
import de.intevation.flys.client.client.services.WQInfoService;
import de.intevation.flys.client.shared.model.WQInfoObject;
import de.intevation.flys.client.shared.model.WQInfoObjectImpl;


/**
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class WQInfoServiceImpl
extends      RemoteServiceServlet
implements   WQInfoService
{
    private static final Logger logger =
        Logger.getLogger(WQInfoServiceImpl.class);


    public static final String ERROR_NO_WQINFO_FOUND =
        "error_no_wqinfo_found";

    public static final String XPATH_WQS = "art:service/art:mainvalues/art:mainvalue";


    public WQInfoObject[] getWQInfo(
        String locale,
        String river,
        double from,
        double to)
    throws ServerException
    {
        logger.info("WQInfoServiceImpl.getWQInfo");

        String url = getServletContext().getInitParameter("server-url");

        Document doc = XMLUtils.newDocument();

        XMLUtils.ElementCreator ec = new XMLUtils.ElementCreator(
            doc,
            ArtifactNamespaceContext.NAMESPACE_URI,
            ArtifactNamespaceContext.NAMESPACE_PREFIX);

        Element mainvalues = ec.create("mainvalues");
        Element riverEl = ec.create("river");
        Element startEl = ec.create("start");
        Element endEl   = ec.create("end");

        riverEl.setTextContent(river);
        startEl.setTextContent(Double.valueOf(from).toString());
        endEl.setTextContent(Double.valueOf(to).toString());

        mainvalues.appendChild(riverEl);
        mainvalues.appendChild(startEl);
        mainvalues.appendChild(endEl);

        doc.appendChild(mainvalues);

        HttpClient client = new HttpClientImpl(url, locale);

        try {
            Document result = client.callService(url, "mainvalues", doc);

            logger.debug("Extract wq info objects now.");
            WQInfoObject[] objects = extractWQInfoObjects(result);

            if (objects != null && objects.length > 0) {
                return objects;
            }
        }
        catch (ConnectionException ce) {
            logger.error(ce, ce);
        }

        throw new ServerException(ERROR_NO_WQINFO_FOUND);
    }


    /**
     * Extracts all wq info objects from <i>result</i> document.
     *
     * @param result The document retrieved by the server.
     *
     * @return a list of WQInfoObjects.
     */
    protected WQInfoObject[] extractWQInfoObjects(Document result)
    throws    ServerException
    {
        NodeList list = (NodeList) XMLUtils.xpath(
            result,
            XPATH_WQS,
            XPathConstants.NODESET,
            ArtifactNamespaceContext.INSTANCE);

        if (list == null || list.getLength() == 0) {
            logger.warn("No wq info found.");

            throw new ServerException(ERROR_NO_WQINFO_FOUND);
        }

        int num = list.getLength();
        logger.debug("Response contains " + num + " objects.");

        List<WQInfoObject> objects =
            new ArrayList<WQInfoObject>(num);

        for (int i = 0; i < num; i++) {
            WQInfoObject obj = buildWQInfoObject(list.item(i));

            if (obj != null) {
                objects.add(obj);
            }
        }

        logger.debug("Retrieved " + objects.size() + " wq values");

        return (WQInfoObject[])
            objects.toArray(new WQInfoObject[num]);
    }


    /**
     * Extracts information for a single wq info object and intializes an
     * WQInfoObject with them.
     *
     * @param node The node that contains the information.
     *
     * @return a valid WQInfoObject.
     */
    protected WQInfoObject buildWQInfoObject(Node node) {
        String name = XMLUtils.xpathString(
            node, "@name", ArtifactNamespaceContext.INSTANCE);

        String type = XMLUtils.xpathString(
            node, "@type", ArtifactNamespaceContext.INSTANCE);

        String value = XMLUtils.xpathString(
            node, "@value", ArtifactNamespaceContext.INSTANCE);


        if (name != null && type != null) {
            try {
                return new WQInfoObjectImpl(
                    name,
                    type,
                    new Double(value));
            }
            catch (NumberFormatException nfe) {
                logger.warn(nfe.getLocalizedMessage());
            }
        }

        logger.warn("Invalid wq info object found.");

        return null;
    }
}
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