package de.intevation.flys.artifacts.context;

import java.util.Map;

import org.apache.log4j.Logger;

import org.w3c.dom.Document;

import de.intevation.artifactdatabase.DefaultArtifactContext;
import de.intevation.artifacts.CallContext;
import de.intevation.flys.exports.OutGenerator;


/**
 * This class is used to store application wide information in a global context.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class FLYSContext extends DefaultArtifactContext {

    /** The logger used in this class. */
    private static Logger logger = Logger.getLogger(FLYSContext.class);

    /** The key that is used to store the StateEngine in the context. */
    public static final String ARTIFACT_KEY =
        "artifact";

    /** The key that is used to store the TransitionEngine in the context. */
    public static final String TRANSITION_ENGINE_KEY =
        "artifact.transition.engine";

    /** The key that is used to store the StateEngine in the context. */
    public static final String STATE_ENGINE_KEY =
        "artifact.state.engine";

    /** The key that is used to store the Map of OutGenerator classes in the
     * context. */
    public static final String OUTGENERATORS_KEY =
        "flys.export.outgenerators";

    /** The key that is used to store the map of themes in the context. */
    public static final String THEMES =
        "flys.themes.map";

    /** The key that is used to store a map of theme mappings in the context. */
    public static final String THEME_MAPPING =
        "flys.themes.mapping.map";

    /** The key that is used to store a map of WMS urls for each river. */
    public static final String RIVER_WMS =
        "flys.floodmap.river.wms";

    /** The key that is used to store an instance of Scheduler in the context.*/
    public static final String SCHEDULER =
        "flys.wsplgen.scheduler";


    /**
     * The default constructor.
     */
    public FLYSContext() {
        super();
    }


    /**
     * A constructor with a config document.
     */
    public FLYSContext(Document config) {
        super(config);
    }

    /**
     * Returns the OutGenerator for a specified <i>type</i>.
     *
     * @param name The name of the output type.
     * @param type Defines the type of the desired OutGenerator.
     *
     * @return Instance of an OutGenerator for specified <i>type</i>.
     */
    public static OutGenerator getOutGenerator(
        CallContext context,
        String      name,
        String      type)
    {

        FLYSContext flysContext = context instanceof FLYSContext
            ? (FLYSContext) context
            : (FLYSContext) context.globalContext();

        Map<String, Class> generators = (Map<String, Class>)
            flysContext.get(FLYSContext.OUTGENERATORS_KEY);

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

        Class clazz = generators.get(name);

        try {
            return clazz != null ? (OutGenerator) clazz.newInstance() : null;
        }
        catch (InstantiationException ie) {
            logger.error(ie, ie);
        }
        catch (IllegalAccessException iae) {
            logger.error(iae, iae);
        }

        return null;
    }
}
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