DirectTag.java

/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library 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 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library 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.
 */

package com.liferay.taglib;

import static javax.servlet.jsp.tagext.Tag.SKIP_BODY;

import com.liferay.portal.kernel.io.unsync.UnsyncStringWriter;
import com.liferay.taglib.servlet.PageContextFactoryUtil;
import com.liferay.taglib.servlet.PipingPageContext;

import java.util.function.Consumer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyContent;
import javax.servlet.jsp.tagext.BodyTag;
import javax.servlet.jsp.tagext.Tag;

/**
 * @author Shuyang Zhou
 */
public interface DirectTag extends Tag {

	public default void doBodyTag(
			HttpServletRequest request, HttpServletResponse response,
			Consumer<PageContext> consumer)
		throws JspException {

		doBodyTag(PageContextFactoryUtil.create(request, response), consumer);
	}

	public default void doBodyTag(
			PageContext pageContext, Consumer<PageContext> consumer)
		throws JspException {

		setPageContext(pageContext);

		int start = doStartTag();

		if (start == SKIP_BODY) {
			doEndTag();

			return;
		}

		if (this instanceof BodyTag) {
			BodyTag bodyTag = (BodyTag)this;

			JspWriter jspWriter = pageContext.getOut();

			if (start == BodyTag.EVAL_BODY_BUFFERED) {
				jspWriter = pageContext.pushBody();

				bodyTag.setBodyContent((BodyContent)jspWriter);

				bodyTag.doInitBody();
			}

			do {
				consumer.accept(pageContext);
			}
			while (bodyTag.doAfterBody() == BodyTag.EVAL_BODY_AGAIN);

			if (start == BodyTag.EVAL_BODY_BUFFERED) {
				pageContext.popBody();
			}
		}
		else {
			consumer.accept(pageContext);
		}

		doEndTag();
	}

	public default String doBodyTagAsString(
			HttpServletRequest request, HttpServletResponse response,
			Consumer<PageContext> consumer)
		throws JspException {

		return doBodyTagAsString(
			PageContextFactoryUtil.create(request, response), consumer);
	}

	public default String doBodyTagAsString(
			PageContext pageContext, Consumer<PageContext> consumer)
		throws JspException {

		UnsyncStringWriter unsyncStringWriter = new UnsyncStringWriter();

		doBodyTag(
			new PipingPageContext(pageContext, unsyncStringWriter), consumer);

		return unsyncStringWriter.toString();
	}

	public default void doTag(
			HttpServletRequest request, HttpServletResponse response)
		throws JspException {

		doTag(PageContextFactoryUtil.create(request, response));
	}

	public default void doTag(PageContext pageContext) throws JspException {
		setPageContext(pageContext);

		doStartTag();
		doEndTag();
	}

	public default String doTagAsString(
			HttpServletRequest request, HttpServletResponse response)
		throws JspException {

		return doTagAsString(PageContextFactoryUtil.create(request, response));
	}

	public default String doTagAsString(PageContext pageContext)
		throws JspException {

		UnsyncStringWriter unsyncStringWriter = new UnsyncStringWriter();

		doTag(new PipingPageContext(pageContext, unsyncStringWriter));

		return unsyncStringWriter.toString();
	}

}