001// Copyright 2004, 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.event;
016
017import java.util.EventListener;
018
019/**
020 *  An interface for objects that want to take part in the validation of the page.
021 *
022 *  @author Mindbridge
023 *  @since 3.0
024 **/
025
026public interface PageValidateListener extends EventListener
027{
028    /**
029     *  Invoked by the page from its
030     *  {@link org.apache.tapestry.IPage#validate(org.apache.tapestry.IRequestCycle)} method.
031     *
032     *  <p>May throw a {@link org.apache.tapestry.PageRedirectException}, to redirect the user
033     *  to an appropriate part of the system (such as, a login page).
034     **/
035
036    public void pageValidate(PageEvent event);
037}