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    
015    package org.apache.tapestry.form;
016    
017    import org.apache.tapestry.IMarkupWriter;
018    import 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     */
026    public 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        void renderContribution(IMarkupWriter writer, IRequestCycle cycle,
044                FormComponentContributorContext context, IFormComponent field);
045    }