XMLParser


1   //
2   //                                   ____.
3   //                       __/\ ______|    |__/\.     _______
4   //            __   .____|    |       \   |    +----+       \
5   //    _______|  /--|    |    |    -   \  _    |    :    -   \_________
6   //   \\______: :---|    :    :           |    :    |         \________>
7   //           |__\---\_____________:______:    :____|____:_____\
8   //                                      /_____|
9   //
10  //                 . . . i n   j a h i a   w e   t r u s t . . .
11  //
12  //
13  //
14  //  XMLParser
15  //
16  //  Loom    11.01.2001
17  //  NK      13.01.2001 Factorised as a utils class
18  //
19  
20  package org.jahia.utils.xml;
21  
22  import java.util.Vector  ;
23  
24  import org.jahia.exceptions.JahiaException;
25  import org.w3c.dom.Element  ;
26  import org.w3c.dom.NamedNodeMap  ;
27  import org.w3c.dom.Node  ;
28  import org.w3c.dom.NodeList  ;
29  
30  
31  /**
32   * Some tools for loading up data from an xml file
33   *
34   * @author Loom
35   * @version 1.0
36   */
37  public class XMLParser {
38  
39      private static final String   CANT_READ_FILE_MSG = "Can't read XML file";
40      private static final String   ERROR_READING_FILE_MSG = "Error reading file";
41      private static final String   PARAMETER_TAG = "parameter";
42      private static final String   PARAMETER_TAG_NAME_ATTRIBUTE = "name";
43  
44  
45      /**
46       * Processes through all the parameter tags of a given node to find the value of
47       * a certain named parameter
48       *
49       *
50       * @return (String) the value of the parameter, null if not found , "" if value=empty
51       */
52      public static String   getParameterValue( Node   paramParent,
53                                      String   parameterName)
54                                      throws JahiaException {
55  
56          if (!paramParent.hasChildNodes()) {
57              throw new JahiaException("No parameters available on portlet XML tag",
58                       "Parent has no children at all",
59                       JahiaException.CRITICAL_SEVERITY,
60                       JahiaException.CONFIG_ERROR);
61          }
62  
63          Node   curNode = paramParent.getFirstChild();
64          while (curNode != null) {
65  
66              //JahiaConsole.println("XMLParser.getParameterValue", "Looking for param...["+curNode.getNodeName()+"]");
67              // let's go through all the children nodes
68              if (curNode.getNodeType() == Node.ELEMENT_NODE) {
69  
70                  if (curNode.getNodeName().equalsIgnoreCase(PARAMETER_TAG)) {
71                      // we have found a parameter tag, let's check further for match of param name
72                      NamedNodeMap   attr = curNode.getAttributes();
73                      Node   paramAttrNode = attr.getNamedItem(PARAMETER_TAG_NAME_ATTRIBUTE);
74                      if (paramAttrNode != null) {
75  
76                          if (paramAttrNode.getNodeValue().equalsIgnoreCase(parameterName)) {
77                              // we found the parameter
78                              //JahiaConsole.println("XMLParser.getParameterValue", "Found parameter " + parameterName);
79                              // we must now extract value of text node below this node.
80                              Node   textNode = curNode.getFirstChild();
81                              if ( textNode == null ){ // check this otherwise nullpointer exception NK
82                                  return "";
83                              } else {
84                                  if (textNode.getNodeType() == Node.TEXT_NODE) {
85                                      return textNode.getNodeValue();
86                                  } else {
87                                      throw new JahiaException(ERROR_READING_FILE_MSG,
88                                      "Value of paramater is not in correct format, should only be text",
89                                      JahiaException.CRITICAL_SEVERITY,
90                                      JahiaException.CONFIG_ERROR);
91                                  }
92                              }
93                          }
94                      } else {
95                          throw new JahiaException(ERROR_READING_FILE_MSG,
96                              "No attribute name found on parameter !",
97                              JahiaException.CRITICAL_SEVERITY,
98                              JahiaException.CONFIG_ERROR);
99                      }
100                 }
101             } else {
102                 // we just ignore other type of tags
103             }
104             curNode = curNode.getNextSibling();
105        }
106 
107        return null; // better return null than throw an exception , NK ?
108 
109     }
110 
111 
112 
113     /**
114      * nextChildOfTag
115      * Go to the next Child Element Node that is equals
116      * with the gived tag value
117      *
118      * @param (Node) startNode, the parent node
119      * @param (String) tag, the tag name
120      * @author NK
121      */
122     public static Node   nextChildOfTag( Node   startNode,
123                               String   tagName
124                             ) throws JahiaException {
125 
126         /*
127         JahiaConsole.println(">>", " nextChildOfTag, tag " + tagName + " started ");
128         */
129 
130         Vector   childs = getChildNodes(startNode,tagName);
131         int size = childs.size();
132         for ( int i=0 ; i<size; i++ ){
133             Node   child = (Node  )childs.get(i);
134             if (child.getNodeName().equalsIgnoreCase(tagName)){
135                 /*
136                 JahiaConsole.println(">>", " nextChildOfTag, current child = " + child.getNodeName() );
137                 */
138                 return child;
139             }
140         }
141 
142         return null;
143     }
144 
145 
146     /**
147      * lastChildOfTag
148      * Go to the last Child Element Node that is equals
149      * with the gived tag value
150      *
151      * @param (Node) parentNode, the parent node
152      * @param (String) tag, the tag name
153      * @return (Node) the last child of this tag or null if not found
154      * @author NK
155      */
156     public static Node   lastChildOfTag( Node   parentNode,
157                               String   tagName
158                             ) throws JahiaException {
159 
160         /*
161         JahiaConsole.println(">>", " nextChildOfTag, tag " + tagName + " started ");
162         */
163 
164         Vector   childs = getChildNodes(parentNode,tagName);
165         int size = childs.size();
166         for ( int i=0 ; i<size; i++ ){
167             Node   child = (Node  )childs.get(i);
168             if ( child.getNodeName().equalsIgnoreCase(tagName) && (i==size-1) ){
169                 /*
170                 JahiaConsole.println(">>", " nextChildOfTag, current child = " + child.getNodeName() );
171                 */
172                 return child;
173             }
174             return null;
175         }
176 
177         return null;
178     }
179 
180 
181     /**
182      * Get a Vector of child nodes equals with a gived tag
183      *
184      * @param (Node) startNode, the parent node
185      * @param (String) tagName, the Children's tag name
186      * @return (Vector) childs, a Vector of child node
187      * @author NK
188      */
189     public static Vector   getChildNodes( Node   parentNode,
190                                 String   tagName
191                               ) throws JahiaException {
192 
193         Vector   childs = new Vector  ();
194 
195         NodeList   nodeList = parentNode.getChildNodes();
196 
197         if ( nodeList != null ) {
198 
199             int size = nodeList.getLength();
200             for ( int i=0; i<size ; i++ ){
201                 Node   nodeItem = null;
202                 nodeItem = nodeList.item(i);
203                 /*
204                 JahiaConsole.println(">>", " getChildNodes, current child node = " + nodeItem.getNodeName() );
205                 */
206                 if ( nodeItem.getNodeName().equalsIgnoreCase(tagName) ){
207                     childs.add(nodeItem);
208                 }
209             }
210         }
211 
212         return childs;
213     }
214 
215 
216     /**
217      * Return the value of a Node's Attribute
218      *
219      * @param (Node) parentNode the parent node
220      * @param (String) attributeName , the name of a gived attribute
221      * @return (String) the value or null
222      * @author NK
223      */
224     public static String   getAttributeValue(Node   parentNode, String   attributeName){
225 
226         NamedNodeMap   attribs = parentNode.getAttributes();
227         //System.out.println(" node " + parentNode.getNodeName() + " has " + attribs.getLength() + " attributes") ;
228         Node   attribNode = attribs.getNamedItem(attributeName);
229         if ( attribNode != null ){
230             //System.out.println(" node " + parentNode.getNodeName() + ", " + attributeName + " =" + attribNode.getNodeValue() ) ;
231             return attribNode.getNodeValue();
232         }
233         return null;
234     } // end getAttributeValue()
235 
236 
237    /**
238     * Set the attibute of a node only if the value is not null or empty
239     *
240     * @param (ElementNode) a node
241     * @param (String) attribName , the name of the attribute
242     * @param (String) value, the value of the attribute
243     */
244    public static void setAttribute( Element   nodeItem,
245                              String   attribName,
246                              String   value
247                          ){
248 
249       if ( value != null && value.length()>0 ){
250          nodeItem.setAttribute(attribName, value);
251       }
252 
253    }
254 
255 
256 
257 }
258
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags