001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.html;
018
019import org.apache.juneau.html.annotation.*;
020import org.apache.juneau.serializer.*;
021
022/**
023 * Allows custom rendering of bean property values when serialized as HTML.
024 *
025 * <p>
026 * Associated with bean properties using the {@link Html#render() @Html(render)} annotation.
027 *
028 * <p>
029 * Using this class, you can alter the CSS style and HTML content of the bean property.
030 *
031 * <h5 class='section'>See Also:</h5><ul>
032 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/HtmlRenderAnnotation">@Html(render) Annotation</a>
033 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/HtmlBasics">HTML Basics</a>
034 * </ul>
035 *
036 * @param <T> The bean property type.
037 */
038public abstract class HtmlRender<T> {
039
040   /**
041    * Returns the CSS style of the element containing the bean property value.
042    *
043    * @param session
044    *    The current serializer session.
045    *    Can be used to retrieve properties and session-level information.
046    * @param value The bean property value.
047    * @return The CSS style string, or <jk>null</jk> if no style should be added.
048    */
049   public String getStyle(SerializerSession session, T value) {
050      return null;
051   }
052
053   /**
054    * Returns the delegate value for the specified bean property value.
055    *
056    * <p>
057    * The default implementation simply returns the same value.
058    * A typical use is to return an HTML element using one of the HTML5 DOM beans.
059    *
060    * @param session
061    *    The current serializer session.
062    *    Can be used to retrieve properties and session-level information.
063    * @param value The bean property value.
064    * @return The new bean property value.
065    */
066   public Object getContent(SerializerSession session, T value) {
067      return value;
068   }
069}