CmsElementXml


1   /*
2   * File   : $Source: /usr/local/cvs/opencms/src-modules/com/opencms/template/cache/CmsElementXml.java,v $
3   * Date   : $Date: 2005/05/31 15:51:19 $
4   * Version: $Revision: 1.3 $
5   *
6   * This library is part of OpenCms -
7   * the Open Source Content Mananagement System
8   *
9   * Copyright (C) 2001  The OpenCms Group
10  *
11  * This library is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU Lesser General Public
13  * License as published by the Free Software Foundation; either
14  * version 2.1 of the License, or (at your option) any later version.
15  *
16  * This library is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  * Lesser General Public License for more details.
20  *
21  * For further information about OpenCms, please see the
22  * OpenCms Website: http://www.opencms.org
23  *
24  * You should have received a copy of the GNU Lesser General Public
25  * License along with this library; if not, write to the Free Software
26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27  */
28  
29  package com.opencms.template.cache;
30  
31  import org.opencms.file.CmsObject;
32  import org.opencms.main.CmsException;
33  import org.opencms.main.CmsLog;
34  import org.opencms.security.CmsSecurityException;
35  
36  import com.opencms.legacy.CmsLegacyException;
37  import com.opencms.legacy.CmsXmlTemplateLoader;
38  import com.opencms.template.A_CmsCacheDirectives;
39  import com.opencms.template.CmsCacheDirectives;
40  import com.opencms.template.I_CmsTemplate;
41  
42  import java.util.Hashtable  ;
43  
44  /**
45   * An instance of CmsElementXML represents an requestable Element in the OpenCms
46   * element cache area. It contains all informations to generate the content of this
47   * element. It also stores the variants of once generated content to speed up
48   * performance.
49   *
50   * It points to other depending elements. Theses elements are called to generate
51   * their content on generation-time.
52   *
53   * @author Alexander Lucas
54   * 
55   * @deprecated Will not be supported past the OpenCms 6 release.
56   */
57  public class CmsElementXml extends A_CmsElement {
58  
59      /**
60       * Constructor for an element with the given class and template name.
61       */
62      public CmsElementXml(String   className, String   templateName, CmsCacheDirectives cd, int variantCachesize) {
63          init(className, templateName, cd, variantCachesize);
64      }
65  
66      /**
67       * A construcor which creates an element with the given element
68       * definitions.
69       * @param name the name of this element-definition.
70       * @param className the classname of this element-definition.
71       * @param readAccessGroup The group that may read the element.
72       * @param cd Cache directives for this element
73       * @param defs CmsElementDefinitionCollection for this element.
74       */
75      public CmsElementXml(String   className, String   templateName, CmsCacheDirectives cd, CmsElementDefinitionCollection defs, int variantCachesize) {
76          init(className, templateName, cd, defs, variantCachesize);
77      }
78  
79      /**
80       * Get the content of this element.
81       * @param elementCache Entry point for the element cache
82       * @param cms CmsObject for accessing system resources
83       * @param elDefs Definitions of this element's subelements
84       * @param parameters All parameters of this request
85       * @param methodParameter not used here, only methodelemets need it.
86       * @return Byte array with the processed content of this element.
87       * @throws CmsException
88       */
89      public byte[] getContent(CmsElementCache elementCache, CmsObject cms, CmsElementDefinitionCollection elDefs, String   elementName, Hashtable   parameters, String   methodParameter) throws CmsException  {
90          byte[] result = null;
91  
92          // Merge own element definitions with our parent's definitions
93          CmsElementDefinitionCollection mergedElDefs = new CmsElementDefinitionCollection(elDefs, m_elementDefinitions);
94  
95          // Get out own cache directives
96          A_CmsCacheDirectives cd = getCacheDirectives();
97  
98          CmsElementVariant variant = null;
99  
100         // Now check, if there is a variant of this element in the cache.
101         if(cd.isInternalCacheable()) {
102 
103             checkReadAccess(cms);
104             // check if this Element has a date of expiry
105             if (cd.isTimeCritical() && (m_timestamp < cd.getTimeout().getLastChange())){
106                 // this element is too old, delete the cache
107                 if(this.hasDependenciesVariants()){
108                     // remove all the variants from the extern dep table
109                     CmsXmlTemplateLoader.getOnlineElementCache().getElementLocator().removeElementFromDependencies(
110                                 mergedElDefs.get(elementName).getDescriptor(), this);
111                 }
112                 clearVariantCache();
113             }else{
114                 variant = getVariant(cd.getCacheKey(cms, parameters));
115                 if((variant != null) && variant.isTimeCritical()
116                                      && variant.getNextTimeout() < System.currentTimeMillis()){
117                     // the variant is not longer valid, remove it from the extern dependencies
118                     CmsXmlTemplateLoader.getOnlineElementCache().getElementLocator().removeVariantFromDependencies(
119                                         m_className +"|" + m_templateName +"|" + cd.getCacheKey(cms, parameters), variant);
120                     variant = null;
121                 }
122             }
123             if(variant != null) {
124                 result = resolveVariant(cms, variant, elementCache, mergedElDefs, parameters);
125             }
126         }
127         if(variant == null) {
128             // This element was not found in the variant cache.
129             // We have to generate it by calling the "classic" getContent() method on the template
130             // class.
131 
132             // get template class
133             I_CmsTemplate templateClass = null;
134             try {
135                 templateClass = getTemplateClass(cms, m_className);
136             } catch(Throwable   e) {
137                 if(CmsLog.getLog(this).isErrorEnabled()) {
138                     CmsLog.getLog(this).error("Could not load my template class \"" + m_className + "\"", e);
139                     return e.toString().getBytes();
140                 }
141             }
142 
143             try {
144                 /*if(cd.isInternalCacheable()) {
145                     System.err.println(toString() + " ### Variant not in cache. Must be generated.");
146                 } else {
147                     System.err.println(toString() + " ### Element not cacheable. Generating variant temporarily.");
148                 }*/
149                 // startProcessing() later will be responsible for generating our new variant.
150                 // since the method resolveVariant (THIS method) will be called recursively
151                 // by startProcessing(), we have to pass the current element definitions.
152                 // Unfortunately, there is no other way than putting them into our parameter
153                 // hashtable. For compatibility reasons we are not allowed to change
154                 // the interface of getContent() or startProcessing()
155                 parameters.put("_ELDEFS_", mergedElDefs);
156                 String   templateSelector = null;
157                 try{
158                     templateSelector = mergedElDefs.get(elementName).getTemplateSelector();
159                 }catch(Exception   e){
160                 }
161                 try {
162                     String   theTemplate = m_templateName;
163                     if(theTemplate == null){
164                         try{
165                             theTemplate = mergedElDefs.get("body").getTemplateName();
166                         }catch(Exception   exc){
167                             if(CmsLog.getLog(this).isErrorEnabled()) {
168                                 CmsLog.getLog(this).error("Could not find the body element to get the default template file for " + this.toString(), exc);
169                             }
170                         }
171                     }
172                     result = templateClass.getContent(cms, theTemplate, elementName, parameters, templateSelector);
173                 } catch(Exception   e) {
174                     if(e instanceof CmsException) {
175                         CmsException ce = (CmsException)e;
176                         if(ce instanceof CmsSecurityException) {
177                             // This was an access denied exception.
178                             // This is not very critical at the moment.
179                             if(CmsLog.getLog(this).isDebugEnabled()) {
180                                 CmsLog.getLog(this).debug("Access denied in getContent for template class " + m_className);
181                             }
182                         } else {
183                             // Any other CmsException.
184                             // This could be more critical.
185                             if(CmsLog.getLog(this).isWarnEnabled()) {
186                                 CmsLog.getLog(this).warn("Error in getContent() for template class " + m_className, e);
187                             }
188                         }
189                         throw ce;
190                     } else {
191                         // No CmsException. This is really, really bad!
192                         if(CmsLog.getLog(this).isErrorEnabled()) {
193                             CmsLog.getLog(this).error("Non OpenCms error occured in getContent for template class " + m_className, e);
194                         }
195                         throw new CmsLegacyException(CmsLegacyException.C_UNKNOWN_EXCEPTION, e);
196                     }
197                 }
198             }
199             catch(CmsException e) {
200                 // Clear cache and do logging here
201                 throw e;
202             }
203         }
204         return result;
205     }
206 }
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