view flys-client/src/main/java/de/intevation/flys/client/server/DescribeCollectionServiceImpl.java @ 5779:ebec12def170

Datacage: Add a pool of builders to make it multi threadable. XML DOM is not thread safe. Therefore the old implementation only allowed one thread to use the builder at a time. As the complexity of the configuration has increased over time this has become a bottleneck of the whole application because it took quiet some time to build a result. Furthermore the builder code path is visited very frequent. So many concurrent requests were piled up resulting in long waits for the users. To mitigate this problem a round robin pool of builders is used now. Each of the pooled builders has an independent copy of the XML template and can be run in parallel. The number of builders is determined by the system property 'flys.datacage.pool.size'. It defaults to 4.
author Sascha L. Teichmann <teichmann@intevation.de>
date Sun, 21 Apr 2013 12:48:09 +0200
parents bc06a671ef60
children
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package de.intevation.flys.client.server;

import org.w3c.dom.Document;

import org.apache.log4j.Logger;

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

import de.intevation.artifacts.common.utils.ClientProtocolUtils;

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

import de.intevation.flys.client.shared.exceptions.ServerException;
import de.intevation.flys.client.shared.model.Collection;

import de.intevation.flys.client.client.services.DescribeCollectionService;


/**
 * This service implements a method that queries the DESCRIBE document of a
 * specific collection and returns a Collection object with the information of
 * the document.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class DescribeCollectionServiceImpl
extends      RemoteServiceServlet
implements   DescribeCollectionService
{
    private static final Logger logger =
        Logger.getLogger(DescribeCollectionServiceImpl.class);


    /** The error message key that is thrown if an error occured while
     * describe() a Collection.*/
    public static final String ERROR_DESCRIBE_COLLECTION =
        "error_describe_collection";


    public Collection describe(String uuid, String locale)
    throws ServerException
    {
        logger.info("DescribeCollectionServiceImpl.describe");

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

        Document describe = ClientProtocolUtils.newDescribeCollectionDocument(
            uuid);

        HttpClient client = new HttpClientImpl(url, locale);

        try {
            Document response = (Document) client.doCollectionAction(
                describe, uuid, new DocumentResponseHandler());

            Collection c = CollectionHelper.parseCollection(response);

            if (c == null) {
                throw new ServerException(ERROR_DESCRIBE_COLLECTION);
            }

            logger.debug("Collection successfully parsed.");

            return c;
        }
        catch (ConnectionException ce) {
            logger.error(ce, ce);
        }

        throw new ServerException(ERROR_DESCRIBE_COLLECTION);
    }
}
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