Java JDOM Element isAncestor() Method

The Java JDOM isAncestor() method of Element class is used to check if the current XML element is an ancestor of another XML element. If it is an ancestor, it returns true, else it returns false.

Syntax

Following is the syntax of the Java JDOM Element isAncestor() method −

Element.isAncestor(element);

Parameters

The Java Element.isAncestor() method accepts a single parameter −

element − represents an element object to check against the current Element.

Return Value

The Java isAncestor() method returns a boolean value; true if it is ancestor, false otherwise.

Example 1

Here is the basic example of using the Java JDOM Element isAncestor() method −

import org.jdom2.Element;

public class CheckAncestor {
   public static void main(String args[]) {
      try {	
         Element root = new Element("root");
         Element child = new Element("child");
         Element grandChild = new Element("grandChild");
         child.addContent(grandChild);
         root.addContent(child);
         //check if the root is ancestor
	     System.out.println(root.isAncestor(grandChild));         
      } catch (Exception e) {
    	 e.printStackTrace();
      }
   }
}

The output window displays the boolean value.

true

Example 2

We need to parse the following vehicle.xml file −

<vehicles>
   <twoWheeler>
      <bike>Pulsar</bike>
      <scooty>Activa</scooty>
   </twoWheeler>
   <threeWheeler></threeWheeler>
   <fourWheeler></fourWheeler>
</vehicles>

In the following example, a child element of twoWheeler is passed as an argument to isAncestor() method to check against fourWheeler element.

import java.io.File;
import java.util.List;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.input.SAXBuilder;

public class CheckAncestor {
   public static void main(String args[]) {
      try {	
    	 //Reading the document
    	 SAXBuilder saxBuilder = new SAXBuilder();
    	 File inputFile = new File("vehicle.xml");
    	 Document doc = saxBuilder.build(inputFile);
    	 //Get the root element
    	 Element root = doc.getRootElement();
	     List<Element> elementList = root.getChildren("twoWheeler");
	     Element ele = elementList.get(0);
	     Element fourWheeler = root.getChild("fourWheeler");
	     //check if fourWheeler is ancestor
	     System.out.println(fourWheeler.isAncestor(ele));
      } catch (Exception e) {
    	 e.printStackTrace();
      }
   }
}

The output window displays the boolean value.

false