/*
 * Copyright (c) 2002-2012 Alibaba Group Holding Limited.
 * All rights reserved.
 *
 * 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 com.alibaba.citrus.service.mail.builder.content;

import static com.alibaba.citrus.service.mail.MailConstant.*;

import javax.mail.Multipart;
import javax.mail.internet.MimeMultipart;

/**
 * 自适应的邮件内容。
 * <p>
 * 通常用这种形式同时发送一个邮件的纯文本和HTML版本，邮件客户端会自动选择显示哪一个版本。
 * 如果一个邮件客户端不支持HTML，用户将看到纯文本的邮件。在支持HTML的平台上，用户将看到更漂亮的HTML邮件。
 * </p>
 *
 * @author Michael Zhou
 */
public class AlternativeMultipartContent extends MultipartContent {
    /** 取得<code>Multipart</code>的实现。 */
    @Override
    protected Multipart getMultipart() {
        return new MimeMultipart(CONTENT_TYPE_MULTIPART_SUBTYPE_ALTERNATIVE);
    }

    @Override
    protected AlternativeMultipartContent newInstance() {
        return new AlternativeMultipartContent();
    }
}