com.semanticcms.core.servlet.Component Maven / Gradle / Ivy

Go to download
/*
 * semanticcms-core-servlet - Java API for modeling web page content and relationships in a Servlet environment.
 * Copyright (C) 2016, 2017, 2019, 2020, 2021, 2022  AO Industries, Inc.
 *     [email protected]
 *     7262 Bull Pen Cir
 *     Mobile, AL 36695
 *
 * This file is part of semanticcms-core-servlet.
 *
 * semanticcms-core-servlet is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * semanticcms-core-servlet is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with semanticcms-core-servlet.  If not, see .
 */

package com.semanticcms.core.servlet;

import com.aoapps.html.servlet.DocumentEE;
import com.semanticcms.core.model.Page;
import java.io.IOException;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * A component is able to render itself within the page.  The theme will
 * call all registered components at the correct stages of page rendering.
 */
@FunctionalInterface
public interface Component {

  /**
   * 
   * Renders a component in the output stream.
   * 
   * 
   * This will be called for each of the component positions as the page
   * is rendered by the theme.  A component that does not apply to the given
   * view, page, or position should take no action and return quickly.
   * 
   *
   * @param view  The view that is currently being rendered.  May be {@code null} during error handling.
   * @param page  The page that is currently being rendered.  May be {@code null} during error handling.
   */
  // TODO: Different methods for each position, with default no-ops.
  //       No more "ComponentPosition".
  //       Pass more specific *Content types rather than generic Document
  void doComponent(
      ServletContext servletContext,
      HttpServletRequest request,
      HttpServletResponse response,
      DocumentEE document,
      View view,
      Page page,
      ComponentPosition position
  ) throws ServletException, IOException;
}