EncoderXStreamInitializer.java

package org.geoserver.notification.common;

import java.util.List;

import org.geoserver.platform.GeoServerExtensions;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
import com.thoughtworks.xstream.converters.reflection.ReflectionProvider;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.mapper.Mapper;

public class EncoderXStreamInitializer implements NotificationXStreamInitializer {

    /**
     * Alias for encoder tag of in xml configuration
     */
    public String name;

    /**
     * Class to use for encoder with filed 'name'
     */
    public Class<? extends NotificationEncoder> clazz;

    /**
     * Define an alias for the {@link DefaultNotificationProcessor#encoder encoder}<br>
     * Define a class for the {@link NotificationEncoder}<br>
     * An example of encoder configuration section in notifier.xml is:
     *
     * <pre>
     *  {@code
     *  <genericProcessor>
     *           <geonodeEncoder>
     *           ...
     *           </geonodeEncoder>
     * </genericProcessor>
     *  }
     * </pre>
     *
     * @param xs XStream object
     *
     */
    public EncoderXStreamInitializer(String name, Class<? extends NotificationEncoder> clazz) {
        super();
        this.name = name;
        this.clazz = clazz;
    }

    @Override
    public void init(XStream xs) {
        xs.aliasAttribute(DefaultNotificationProcessor.class, "encoder", name);
        xs.registerLocalConverter(DefaultNotificationProcessor.class, "encoder",
                new EncoderConverter(xs.getMapper(), xs.getReflectionProvider(), this));
    }

    /**
     *
     * @author Alessio Fabiani, GeoSolutions S.A.S.
     *
     */
    static public class EncoderConverter extends ReflectionConverter {

        private EncoderXStreamInitializer encoderXStreamInitializer;

        /**
         * @param mapper
         * @param reflectionProvider
         * @param senderXStreamInitializer
         */
        public EncoderConverter(Mapper mapper, ReflectionProvider reflectionProvider,
                EncoderXStreamInitializer encoderXStreamInitializer) {
            super(mapper, reflectionProvider);
            this.encoderXStreamInitializer = encoderXStreamInitializer;
        }

        @SuppressWarnings({ "rawtypes", "unchecked" })
        @Override
        public boolean canConvert(Class clazz) {
            return clazz.isAssignableFrom(encoderXStreamInitializer.clazz);
        }

        @Override
        public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
            NotificationEncoder encoder = null;
            String nodeName = reader.getNodeName();

            List<EncoderXStreamInitializer> serializers = GeoServerExtensions.extensions(EncoderXStreamInitializer.class);

            for(EncoderXStreamInitializer serializer : serializers) {
                if (serializer.name.equals(nodeName)) {
                    try {
                        encoder = serializer.clazz.newInstance();
                        encoder = (NotificationEncoder) context.convertAnother(encoder, serializer.clazz);
                        break;
                    } catch (InstantiationException e) {
                        throw new RuntimeException(e);
                    } catch (IllegalAccessException e) {
                        throw new RuntimeException(e);
                    }
                }
            }

            return encoder;
        }
    }
}