    001    // Copyright 2010, 2011 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    // http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.internal.transform;
    016
    017    import org.apache.tapestry5.runtime.ComponentEvent;
    018
    019    /**
    020     * Supplies one parameter value when invoking a component event handler method. In general,
    021     * this involves extracting a value form the event's context and coercing it to a type
    022     * appropriate to the parameter.
    023     * <p/>
    024     * These values are accumulated and used to invoke the event handler method.
    025     *
    026     * @since 5.2.0
    027     */
    028    public interface EventHandlerMethodParameterProvider
    029    {
    030        /**
    031         * Extract the value and coerce it to the correct type.
    032         *
    033         * @return value that can be passed as a method parameter
    034         */
    035        Object valueForEventHandlerMethodParameter(ComponentEvent event);
    036    }