    001// Licensed under the Apache License, Version 2.0 (the "License");
    002// you may not use this file except in compliance with the License.
    003// You may obtain a copy of the License at
    004//
    005// http://www.apache.org/licenses/LICENSE-2.0
    006//
    007// Unless required by applicable law or agreed to in writing, software
    008// distributed under the License is distributed on an "AS IS" BASIS,
    009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    010// See the License for the specific language governing permissions and
    011// limitations under the License.
    012
    013package org.apache.tapestry5.internal.transform;
    014
    015import org.apache.tapestry5.runtime.ComponentEvent;
    016
    017/**
    018 * Supplies one parameter value when invoking a component event handler method. In general,
    019 * this involves extracting a value form the event's context and coercing it to a type
    020 * appropriate to the parameter.
    021 *
    022 * These values are accumulated and used to invoke the event handler method.
    023 *
    024 * @since 5.2.0
    025 */
    026public interface EventHandlerMethodParameterProvider
    027{
    028    /**
    029     * Extract the value and coerce it to the correct type.
    030     *
    031     * @return value that can be passed as a method parameter
    032     */
    033    Object valueForEventHandlerMethodParameter(ComponentEvent event);
    034}