content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * 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.
   *
   * For further information about Alkacon Software, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.jsp.jsonpart;
  
  import org.opencms.flex.CmsFlexController;
  import org.opencms.main.CmsLog;
  
  import java.io.IOException;
  
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.tagext.TagSupport;
  import javax.servlet.jsp.tagext.TryCatchFinally;
  
  import org.apache.commons.logging.Log;
  
  /**
   * Tag used to convert the HTML output of this tag's contents to encoded JSON.<p>
   *
   * It only makes sense to use this tag in combination with the servlet filter org.opencms.jsp.jsonpart.CmsJsonPartFilter.
   * This tag converts the text generated by its contained JSP code and converts it into a special encoded form, which is then
   * used by the filter to generate JSON. The 'element' attribute on this tag can be used to control the JSON key which will be used for
   * the content.
   */
  public class CmsJspTagJsonPart extends TagSupport implements TryCatchFinally {
  
      /** Serial version id. */
      private static final long serialVersionUID = 1L;
  
      /** Log instance for this class. */
      private static final Log LOG = CmsLog.getLog(CmsJspTagJsonPart.class);
  
      /** The name to be used as a key for the JSON part. */
      private String m_element;
  
      /** Variable to keep track of whether we still need to write the end marker. */
      private boolean m_needEnd;
  
      /**
       * @see javax.servlet.jsp.tagext.TryCatchFinally#doCatch(java.lang.Throwable)
       */
      public void doCatch(Throwable arg0) throws Throwable {
  
          throw arg0;
      }
  
      /**
       * @see javax.servlet.jsp.tagext.TagSupport#doEndTag()
       */
      @Override
      public int doEndTag() throws JspException {
  
          if (CmsFlexController.isCmsRequest(pageContext.getRequest())
              && CmsJsonPartFilter.isJsonRequest(pageContext.getRequest())) {
              try {
                  pageContext.getOut().write(CmsJsonPart.END);
                  m_needEnd = false;
              } catch (IOException e) {
                  throw new JspException(e);
              }
          }
          return EVAL_PAGE;
      }
  
      /**
       * @see javax.servlet.jsp.tagext.TryCatchFinally#doFinally()
       */
      public void doFinally() {
  
          if (m_needEnd) { // Exception happened before we could write the end marker
              m_needEnd = false;
              try {
                  pageContext.getOut().write(CmsJsonPart.END);
              } catch (IOException e) {
                  LOG.error(e.getLocalizedMessage(), e);
              }
          }
      }
  
      /**
       * @see javax.servlet.jsp.tagext.TagSupport#doStartTag()
       */
      @Override
      public int doStartTag() throws JspException {
  
          if (null != findAncestorWithClass(this, CmsJspTagJsonPart.class)) {
              throw new JspException("cms:jsonpart tag must not be nested!");
          }
  
          if (CmsFlexController.isCmsRequest(pageContext.getRequest())
              && CmsJsonPartFilter.isJsonRequest(pageContext.getRequest())) {
              try {
                  pageContext.getOut().write(CmsJsonPart.getHeader(getElement()));
                  m_needEnd = true;
              } catch (IOException e) {
                  throw new JspException(e);
              }
          }
          return EVAL_BODY_INCLUDE;
      }
  
      /**
       * Returns the name to be used as the JSON key.<p>
       *
       * @return the name to be used as a JSON key
       */
      public String getElement() {
  
          return m_element;
      }
  
      /**
       * Sets the name to be used as a JSON key.<p>
       *
       * @param elementName the name to be used as a JSON key
       */
      public void setElement(String elementName) {
  
          m_element = elementName;
      }
  
  }
  