MapLayerFactoryPlugin.java

package org.mapfish.print.map;

import org.mapfish.print.attribute.map.MapLayer;
import org.mapfish.print.config.Template;

import java.io.IOException;
import java.util.Set;
import javax.annotation.Nonnull;

/**
 * Parses layer request data and creates a MapLayer from it.
 *
 * @param <Param> the type of object that will be populated from the JSON and passed to the factory to
 *               create the layer.
 */
public interface MapLayerFactoryPlugin<Param> {

    /**
     * Return a set of all the values the json 'type' property should have for this plugin to apply
     * typenames <em>MUST</em> be lowercase.
     */
    Set<String> getTypeNames();

    /**
     * Create an instance of a param object.  Each instance must be new and unique. Instances must
     * <em>NOT</em> be shared.
     * <p></p>
     * The object will be populated from the json.  Each public field will be populated by looking up the
     * value in the json.
     * <p></p>
     * The same mechanism used for reading from the JSON into the param object is also used for parsing the
     * JSON into {@link org.mapfish.print.attribute.Attribute} value objects.
     * See
     * {@link org.mapfish.print.attribute.ReflectiveAttribute#createValue(org.mapfish.print.config.Template)}()}
     * for details on how the parsing mechanism works.
     */
    Param createParameter();

    /**
     * Inspect the json data and return Optional<MapLayer> or Optional.absent().
     * @param template the configuration related to the current request.
     * @param layerData an object populated from the json for the layer
     */
    @Nonnull
    MapLayer parse(
            @Nonnull Template template,
            @Nonnull Param layerData) throws IOException;
}