001// Copyright 2005 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
015package org.apache.tapestry.form;
016
017import org.apache.tapestry.IMarkupWriter;
018import org.apache.tapestry.IRequestCycle;
019
020/**
021 * Interface for objects that contribute client-side events back to a form
022 * 
023 * @author Paul Ferraro
024 * @since 4.0
025 */
026public interface FormComponentContributor
027{
028    /**
029     * Invoked by a form component after it finishes rendering its tag (but before the tag is
030     * closed) to allow this object to contribute to the component's rendering process. Typically
031     * used by Validators and Translators to add javascript methods to the form's submit event
032     * handler.
033     * 
034     * @param writer
035     *            allows contributor to write additional attributes into the component's tag
036     * @param cycle
037     *            for accessing request information
038     * @param context
039     *            utilities for genering messages and client-side validation
040     * @param field
041     *            the field for which contributions are being rendered
042     */
043    public void renderContribution(IMarkupWriter writer, IRequestCycle cycle,
044            FormComponentContributorContext context, IFormComponent field);
045}