package de.intevation.flys.artifacts.services;

import java.sql.Connection;
import java.sql.SQLException;

import org.w3c.dom.Document;

import org.apache.log4j.Logger;

import java.util.Map;
import java.util.HashMap;

import de.intevation.artifacts.CallMeta;
import de.intevation.artifacts.GlobalContext;

import de.intevation.artifactdatabase.DefaultService;

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

import de.intevation.artifacts.common.ArtifactNamespaceContext;

import de.intevation.flys.artifacts.services.meta.Builder;
import de.intevation.flys.artifacts.services.meta.DataCage;

import de.intevation.flys.backend.SessionHolder;

import org.hibernate.Session;

import org.hibernate.jdbc.Work;

public class MetaDataService
extends      DefaultService
{
    private static Logger log = Logger.getLogger(MetaDataService.class);

    public static final String XPATH_RIVER = "/art:river/text()";

    public MetaDataService() {
    }

    protected static Map<String, Object> extractParameters(Document data) {
        HashMap<String, Object> parameters = new HashMap<String, Object>();

        String river = XMLUtils.xpathString(
            data, XPATH_RIVER, ArtifactNamespaceContext.INSTANCE);

        if (river == null || (river = river.trim()).length() == 0) {
            river = "%"; // matches all rivers
        }

        parameters.put("river", river);

        return parameters;
    }

    @Override
    public Document process(
        Document      data,
        GlobalContext globalContext,
        CallMeta      callMeta
    ) {
        log.debug("MetaDataService.process");

        final Document result = XMLUtils.newDocument();

        final Builder builder = DataCage.getInstance().getBuilder();

        if (builder == null) {
            log.error("MetaDataService is not setup properly.");
            return result;
        }

        final Map<String, Object> parameters = extractParameters(data);

        Session session = SessionHolder.acquire();
        try {
            session.doWork(new Work() {
                @Override
                public void execute(Connection connection)
                throws SQLException
                {
                    log.debug("MetaDataService.execute");
                    builder.build(connection, result, parameters);
                }
            });
        }
        finally {
            session.close();
            SessionHolder.release();
        }

        return result;
    }
}
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