package org.apache.lucene.xmlparser;
import java.io.Reader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
*
*/
public class DOMUtils
{
public static Element getChildByTagOrFail(Element e, String name) throws ParserException
{
Element kid = getChildByTagName(e, name);
if (null == kid)
{
throw new ParserException(e.getTagName() + " missing \"" + name
+ "\" child element");
}
return kid;
}
public static Element getFirstChildOrFail(Element e) throws ParserException
{
Element kid = getFirstChildElement(e);
if (null == kid)
{
throw new ParserException(e.getTagName()
+ " does not contain a child element");
}
return kid;
}
public static String getAttributeOrFail(Element e, String name) throws ParserException
{
String v = e.getAttribute(name);
if (null == v)
{
throw new ParserException(e.getTagName() + " missing \"" + name
+ "\" attribute");
}
return v;
}
public static String getAttributeWithInheritanceOrFail(Element e, String name) throws ParserException
{
String v = getAttributeWithInheritance(e, name);
if (null == v)
{
throw new ParserException(e.getTagName() + " missing \"" + name
+ "\" attribute");
}
return v;
}
public static String getNonBlankTextOrFail(Element e) throws ParserException
{
String v = getText(e);
if (null != v)
v = v.trim();
if (null == v || 0 == v.length())
{
throw new ParserException(e.getTagName() + " has no text");
}
return v;
}
/* Convenience method where there is only one child Element of a given name */
public static Element getChildByTagName(Element e, String name)
{
for (Node kid = e.getFirstChild(); kid != null; kid = kid.getNextSibling())
{
if( (kid.getNodeType()==Node.ELEMENT_NODE) && (name.equals(kid.getNodeName())) )
{
return (Element)kid;
}
}
return null;
}
/**
* Returns an attribute value from this node, or first parent node with this attribute defined
* @param element
* @param attributeName
* @return A non-zero-length value if defined, otherwise null
*/
public static String getAttributeWithInheritance(Element element, String attributeName)
{
String result=element.getAttribute(attributeName);
if( (result==null)|| ("".equals(result) ) )
{
Node n=element.getParentNode();
if((n==element)||(n==null))
{
return null;
}
if(n instanceof Element)
{
Element parent=(Element) n;
return getAttributeWithInheritance(parent,attributeName);
}
return null; //we reached the top level of the document without finding attribute
}
return result;
}
/* Convenience method where there is only one child Element of a given name */
public static String getChildTextByTagName(Element e, String tagName)
{
Element child=getChildByTagName(e,tagName);
if(child!=null)
{
return getText(child);
}
return null;
}
/* Convenience method to append a new child with text*/
public static Element insertChild(Element parent, String tagName, String text)
{
Element child = parent.getOwnerDocument().createElement(tagName);
parent.appendChild(child);
if(text!=null)
{
child.appendChild(child.getOwnerDocument().createTextNode(text));
}
return child;
}
public static String getAttribute(Element element, String attributeName, String deflt)
{
String result=element.getAttribute(attributeName);
if( (result==null)|| ("".equals(result) ) )
{
return deflt;
}
return result;
}
public static float getAttribute(Element element, String attributeName, float deflt)
{
String result=element.getAttribute(attributeName);
if( (result==null)|| ("".equals(result) ) )
{
return deflt;
}
return Float.parseFloat(result);
}
public static int getAttribute(Element element, String attributeName, int deflt)
{
String result=element.getAttribute(attributeName);
if( (result==null)|| ("".equals(result) ) )
{
return deflt;
}
return Integer.parseInt(result);
}
public static boolean getAttribute(Element element, String attributeName,
boolean deflt)
{
String result = element.getAttribute(attributeName);
if ((result == null) || ("".equals(result)))
{
return deflt;
}
return Boolean.valueOf(result).booleanValue();
}
/* Returns text of node and all child nodes - without markup */
//MH changed to Node from Element 25/11/2005
public static String getText(Node e)
{
StringBuilder sb=new StringBuilder();
getTextBuffer(e, sb);
return sb.toString();
}
public static Element getFirstChildElement(Element element)
{
for (Node kid = element.getFirstChild(); kid != null; kid = kid
.getNextSibling())
{
if (kid.getNodeType() == Node.ELEMENT_NODE)
{
return (Element) kid;
}
}
return null;
}
private static void getTextBuffer(Node e, StringBuilder sb)
{
for (Node kid = e.getFirstChild(); kid != null; kid = kid.getNextSibling())
{
switch(kid.getNodeType())
{
case Node.TEXT_NODE:
{
sb.append(kid.getNodeValue());
break;
}
case Node.ELEMENT_NODE:
{
getTextBuffer(kid, sb);
break;
}
case Node.ENTITY_REFERENCE_NODE:
{
getTextBuffer(kid, sb);
break;
}
}
}
}
/**
* Helper method to parse an XML file into a DOM tree, given a reader.
* @param is reader of the XML file to be parsed
* @return an org.w3c.dom.Document object
*/
public static Document loadXML(Reader is)
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = null;
try
{
db = dbf.newDocumentBuilder();
}
catch (Exception se)
{
throw new RuntimeException("Parser configuration error", se);
}
// Step 3: parse the input file
org.w3c.dom.Document doc = null;
try
{
doc = db.parse(new InputSource(is));
//doc = db.parse(is);
}
catch (Exception se)
{
throw new RuntimeException("Error parsing file:" + se, se);
}
return doc;
}
}