Mega Code Archive
Locating a Node by an ID
<![CDATA[
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Attr;
import org.w3c.dom.CDATASection;
import org.w3c.dom.Comment;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
public class DOMEdit {
static public void main(String[] arg) {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setValidating(true);
dbf.setNamespaceAware(true);
dbf.setIgnoringElementContentWhitespace(true);
Document doc = null;
try {
DocumentBuilder builder = dbf.newDocumentBuilder();
builder.setErrorHandler(new MyErrorHandler());
InputSource is = new InputSource("personWithDTD.xml");
doc = builder.parse(is);
findByID(doc, "B");
write(doc);
} catch (Exception e) {
System.err.println(e);
}
}
public static void findByID(Document doc,String idName) {
Element name = doc.getElementById(idName);
if(name == null) {
System.out.println("There is no element with the ID "
+ idName);
} else {
Text text = (Text)name.getFirstChild();
System.out.println("The ID " + idName
+ " locates the name " + text.getData());
}
}
private static final String TAB = " ";
private static void write(Document doc) throws IOException {
outputHeading(doc);
outputElement(doc.getDocumentElement(), "");
}
private static void outputHeading(Document doc) {
System.out.print("<?xml version=\"1.0\"");
DocumentType doctype = doc.getDoctype();
if (doctype != null) {
if ((doctype.getPublicId() == null) && (doctype.getSystemId() == null)) {
System.out.println(" standalone=\"yes\"?>");
} else {
System.out.println(" standalone=\"no\"?>");
}
} else {
System.out.println("?>");
}
}
private static void outputElement(Element node, String indent) {
System.out.print(indent + "<" + node.getTagName());
NamedNodeMap nm = node.getAttributes();
for (int i = 0; i < nm.getLength(); i++) {
Attr attr = (Attr) nm.item(i);
System.out.print(" " + attr.getName() + "=\"" + attr.getValue() + "\"");
}
System.out.println(">");
NodeList list = node.getChildNodes();
for (int i = 0; i < list.getLength(); i++)
outputloop(list.item(i), indent + TAB);
System.out.println(indent + "</" + node.getTagName() + ">");
}
private static void outputText(Text node, String indent) {
System.out.println(indent + node.getData());
}
private static void outputCDATASection(CDATASection node, String indent) {
System.out.println(indent + node.getData() );
}
private static void outputComment(Comment node, String indent) {
System.out.println(indent + "<!-- " + node.getData() + " -->");
}
private static void outputProcessingInstructionNode(ProcessingInstruction node, String indent) {
System.out.println(indent + "<?" + node.getTarget() + " " + node.getData() + "?>");
}
private static void outputloop(Node node, String indent) {
switch (node.getNodeType()) {
case Node.ELEMENT_NODE:
outputElement((Element) node, indent);
break;
case Node.TEXT_NODE:
outputText((Text) node, indent);
break;
case Node.CDATA_SECTION_NODE:
outputCDATASection((CDATASection) node, indent);
break;
case Node.COMMENT_NODE:
outputComment((Comment) node, indent);
break;
case Node.PROCESSING_INSTRUCTION_NODE:
outputProcessingInstructionNode((ProcessingInstruction) node, indent);
break;
default:
System.out.println("Unknown node type: " + node.getNodeType());
break;
}
}
}
class MyErrorHandler implements ErrorHandler {
public void warning(SAXParseException e) throws SAXException {
show("Warning", e);
throw (e);
}
public void error(SAXParseException e) throws SAXException {
show("Error", e);
throw (e);
}
public void fatalError(SAXParseException e) throws SAXException {
show("Fatal Error", e);
throw (e);
}
private void show(String type, SAXParseException e) {
System.out.println(type + ": " + e.getMessage());
System.out.println("Line " + e.getLineNumber() + " Column " + e.getColumnNumber());
System.out.println("System ID: " + e.getSystemId());
}
}
//File: personWithDTD.xml
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE folks [
<!ELEMENT folks (person)*>
<!ELEMENT person (name)>
<!ELEMENT name (#PCDATA)>
<!ATTLIST name nick ID #IMPLIED>
]>
<folks>
<person>
<name nick="Al">Alite Quandry</name>
</person>
<person>
<name nick="Fred">Mush Pushkin</name>
</person>
<person>
<name nick="Alvie">Avarine Spraddle</name>
</person>
</folks>
The ID B locates the name BB
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