package de.intevation.flys.client.server;

import org.w3c.dom.Document;

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

import de.intevation.artifacts.common.ArtifactNamespaceContext;
import de.intevation.artifacts.common.utils.ClientProtocolUtils;
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.artifacts.httpclient.http.response.DocumentResponseHandler;

import de.intevation.flys.client.shared.model.Artifact;
import de.intevation.flys.client.client.services.AdvanceService;


/**
 * This interface provides artifact specific operation ADVANCE.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class AdvanceServiceImpl
extends      RemoteServiceServlet
implements   AdvanceService
{
    public static final String XPATH_RESULT = "/art:result/text()";

    public static final String OPERATION_FAILURE = "FAILED";


    public Artifact advance(String serverUrl, Artifact artifact, String target){
        Document advance = ClientProtocolUtils.newAdvanceDocument(
            artifact.getUuid(),
            artifact.getHash(),
            target);

        HttpClient client = new HttpClientImpl(serverUrl);

        try {
            Document description = (Document) client.advance(
                new de.intevation.artifacts.httpclient.objects.Artifact(
                    artifact.getUuid(),
                    artifact.getHash()),
                advance,
                new DocumentResponseHandler());

            if (description == null) {
                return null;
            }

            String result = XMLUtils.xpathString(
                description,
                XPATH_RESULT,
                ArtifactNamespaceContext.INSTANCE);

            if (result == null || !result.equals(OPERATION_FAILURE)) {
                return (Artifact) new FLYSArtifactCreator().create(description);
            }
        }
        catch (ConnectionException ce) {
            System.err.println(ce.getLocalizedMessage());
        }

        return null;
    }
}
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