/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.wamblee.wicket.page;

import javax.persistence.EntityManager;
import javax.transaction.UserTransaction;

import org.apache.wicket.IPageMap;
import org.apache.wicket.PageParameters;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.model.IModel;
import org.apache.wicket.protocol.http.WebResponse;

/**
 * Base page for wicket applications that allows customization of various
 * bahaviors of the page. This page has no associated markup.
 * 
 * The utility methods {@link #disableCaching()}, {@link #expireImmediately()},
 * and {@link #flushEntityManagerAfterRender(EntityManager)} are provide for
 * quicly adding behaviors. Alternatively, the method
 * {@link #addBehavior(PageBehavior)} can be used.
 * 
 * @author Erik Brakkee
 * 
 */
public class WebApplicationBasePage extends WebPage {

    private CompositePageBehavior behaviors;

    protected WebApplicationBasePage() {
        super();
        init();
    }

    protected WebApplicationBasePage(final IModel<?> model) {
        super(model);
        init();
    }

    protected WebApplicationBasePage(final IPageMap pageMap) {
        super(pageMap);
        init();
    }

    protected WebApplicationBasePage(final IPageMap pageMap,
        final IModel<?> model) {
        super(pageMap, model);
        init();
    }

    protected WebApplicationBasePage(final PageParameters parameters) {
        super(parameters);
        init();
    }

    protected WebApplicationBasePage(final IPageMap pageMap,
        final PageParameters parameters) {
        super(pageMap, parameters);
        init();
    }

    private void init() {
        behaviors = new CompositePageBehavior();
    }

    /**
     * Disables caching. This implies expiry of the page from the page map.
     */
    protected void disableCaching() {
        addBehavior(new DisableCachingBehavior());
    }

    /**
     * Expires the page immediately. Refresh in the browser will lead to an
     * expired page.
     */
    protected void expireImmediately() {
        addBehavior(new ExpirePageImmediatelyBehavior());
    }

    /**
     * Flushes the entitymanager immedately after rendering to make sure that
     * errors are caught early.
     * 
     * @param aEntityManager
     *            Contextual reference to an entity manager.
     */
    protected void flushEntityManagerAfterRender(EntityManager aEntityManager) {
        addBehavior(new FlushEntityManagerBehavior(aEntityManager));
    }

    /**
     * Adds a specific behavior to the page.
     * 
     * @param aBehavior
     *            Behavior to add.
     */
    public void addBehavior(PageBehavior aBehavior) {
        behaviors.add(aBehavior);
    }

    @Override
    protected void onBeforeRender() {
        behaviors.onBeforeRender(this);
        super.onBeforeRender();
    }

    @Override
    protected void setHeaders(WebResponse aResponse) {
        super.setHeaders(aResponse);
        behaviors.setHeaders(this, aResponse);
    }

    @Override
    protected void onAfterRender() {
        super.onAfterRender();
        behaviors.onAfterRender(this);
    }
}