001/* 002 * This library is part of OpenCms - 003 * the Open Source Content Management System 004 * 005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com) 006 * 007 * This library is free software; you can redistribute it and/or 008 * modify it under the terms of the GNU Lesser General Public 009 * License as published by the Free Software Foundation; either 010 * version 2.1 of the License, or (at your option) any later version. 011 * 012 * This library is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * For further information about Alkacon Software, please see the 018 * company website: http://www.alkacon.com 019 * 020 * For further information about OpenCms, please see the 021 * project website: http://www.opencms.org 022 * 023 * You should have received a copy of the GNU Lesser General Public 024 * License along with this library; if not, write to the Free Software 025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 026 */ 027 028package org.opencms.jsp.jsonpart; 029 030import org.opencms.flex.CmsFlexController; 031import org.opencms.main.CmsLog; 032 033import java.io.IOException; 034 035import javax.servlet.jsp.JspException; 036import javax.servlet.jsp.tagext.TagSupport; 037import javax.servlet.jsp.tagext.TryCatchFinally; 038 039import org.apache.commons.logging.Log; 040 041/** 042 * Tag used to convert the HTML output of this tag's contents to encoded JSON.<p> 043 * 044 * It only makes sense to use this tag in combination with the servlet filter org.opencms.jsp.jsonpart.CmsJsonPartFilter. 045 * This tag converts the text generated by its contained JSP code and converts it into a special encoded form, which is then 046 * 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 047 * the content. 048 */ 049public class CmsJspTagJsonPart extends TagSupport implements TryCatchFinally { 050 051 /** Serial version id. */ 052 private static final long serialVersionUID = 1L; 053 054 /** Log instance for this class. */ 055 private static final Log LOG = CmsLog.getLog(CmsJspTagJsonPart.class); 056 057 /** The name to be used as a key for the JSON part. */ 058 private String m_element; 059 060 /** Variable to keep track of whether we still need to write the end marker. */ 061 private boolean m_needEnd; 062 063 /** 064 * @see javax.servlet.jsp.tagext.TryCatchFinally#doCatch(java.lang.Throwable) 065 */ 066 public void doCatch(Throwable arg0) throws Throwable { 067 068 throw arg0; 069 } 070 071 /** 072 * @see javax.servlet.jsp.tagext.TagSupport#doEndTag() 073 */ 074 @Override 075 public int doEndTag() throws JspException { 076 077 if (CmsFlexController.isCmsRequest(pageContext.getRequest()) 078 && CmsJsonPartFilter.isJsonRequest(pageContext.getRequest())) { 079 try { 080 pageContext.getOut().write(CmsJsonPart.END); 081 m_needEnd = false; 082 } catch (IOException e) { 083 throw new JspException(e); 084 } 085 } 086 return EVAL_PAGE; 087 } 088 089 /** 090 * @see javax.servlet.jsp.tagext.TryCatchFinally#doFinally() 091 */ 092 public void doFinally() { 093 094 if (m_needEnd) { // Exception happened before we could write the end marker 095 m_needEnd = false; 096 try { 097 pageContext.getOut().write(CmsJsonPart.END); 098 } catch (IOException e) { 099 LOG.error(e.getLocalizedMessage(), e); 100 } 101 } 102 } 103 104 /** 105 * @see javax.servlet.jsp.tagext.TagSupport#doStartTag() 106 */ 107 @Override 108 public int doStartTag() throws JspException { 109 110 if (null != findAncestorWithClass(this, CmsJspTagJsonPart.class)) { 111 throw new JspException("cms:jsonpart tag must not be nested!"); 112 } 113 114 if (CmsFlexController.isCmsRequest(pageContext.getRequest()) 115 && CmsJsonPartFilter.isJsonRequest(pageContext.getRequest())) { 116 try { 117 pageContext.getOut().write(CmsJsonPart.getHeader(getElement())); 118 m_needEnd = true; 119 } catch (IOException e) { 120 throw new JspException(e); 121 } 122 } 123 return EVAL_BODY_INCLUDE; 124 } 125 126 /** 127 * Returns the name to be used as the JSON key.<p> 128 * 129 * @return the name to be used as a JSON key 130 */ 131 public String getElement() { 132 133 return m_element; 134 } 135 136 /** 137 * Sets the name to be used as a JSON key.<p> 138 * 139 * @param elementName the name to be used as a JSON key 140 */ 141 public void setElement(String elementName) { 142 143 m_element = elementName; 144 } 145 146}