    001    // Copyright 2012 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.runtime;
    016
    017    /**
    018     * Defines a way for different aspects of a page to add callbacks for important lifecycle events.
    019     *
    020     * @see org.apache.tapestry5.ComponentResources#getPageLifecycleCallbackHub()
    021     * @since 5.3.4
    022     */
    023    public interface PageLifecycleCallbackHub
    024    {
    025        /**
    026         * Adds a callback for when the page is first loaded.  Callbacks are invoked in the order they
    027         * are added to the page. They are invoked once and then discarded.
    028         *
    029         * @param callback
    030         *         invoked once, when page is first loaded
    031         * @since 5.3.4
    032         */
    033        void addPageLoadedCallback(Runnable callback);
    034
    035        /**
    036         * Adds a callback for when the page is attached to the request.
    037         *
    038         * @param callback
    039         * @since 5.3.4
    040         */
    041        void addPageAttachedCallback(Runnable callback);
    042
    043        /**
    044         * Adds a callback for when the page is detached from the request.
    045         *
    046         * @param callback
    047         * @since 5.3.4
    048         */
    049        void addPageDetachedCallback(Runnable callback);
    050
    051        /**
    052         * Adds a verify callback, which is allowed while the page is loading. Such callbacks are invoked once,
    053         * after the page has been loaded successfully, and are then discarded. This was added specifically to ensure that components
    054         * only verify that required parameters are bound after all components and mixins of the page have had a chance
    055         * to initialize.
    056         *
    057         * @param callback
    058         *         to be invoked after page loaded
    059         * @since 5.3
    060         */
    061        void addVerifyCallback(Runnable callback);
    062
    063        /**
    064         * A reset occurs when a request for a page arrives that did not originate on the same page. This gives the application a chance to reset the state of the page.
    065         *
    066         * @param callback
    067         *         invoked when a page is activated by link from some other page.
    068         */
    069        void addResetCallback(Runnable callback);
    070    }