How to get the number of siblings of this node in a JTree?

To get the count of siblings of this node, use the getSiblingCount() method. Let’s say you have a node with 4 child nodes. Find the sibling of any of this node’s child node. Here, “eight” is the child node −

eight.getSiblingCount());

Note − Remember, a node is it’s own sibling.

The following is an example to get the number of siblings of this node in a JTree −

Example

<span class="kwd">package</span><span class="pln"> </span><span class="kwd">my</span><span class="pun">;</span>
<span class="kwd">import</span><span class="pln"> javax</span><span class="pun">.</span><span class="pln">swing</span><span class="pun">.</span><span class="typ">JFrame</span><span class="pun">;</span>
<span class="kwd">import</span><span class="pln"> javax</span><span class="pun">.</span><span class="pln">swing</span><span class="pun">.</span><span class="typ">JTree</span><span class="pun">;</span>
<span class="kwd">import</span><span class="pln"> javax</span><span class="pun">.</span><span class="pln">swing</span><span class="pun">.</span><span class="pln">tree</span><span class="pun">.</span><span class="typ">DefaultMutableTreeNode</span><span class="pun">;</span>
<span class="kwd">public</span><span class="pln"> </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">SwingDemo</span><span class="pln"> </span><span class="pun">{</span>
<span class="kwd">   public</span><span class="pln"> </span><span class="kwd">static</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> main</span><span class="pun">(</span><span class="typ">String</span><span class="pun">[]</span><span class="pln"> args</span><span class="pun">)</span><span class="pln"> </span><span class="kwd">throws</span><span class="pln"> </span><span class="typ">Exception</span><span class="pln"> </span><span class="pun">{</span>
<span class="typ">      JFrame</span><span class="pln"> frame </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">JFrame</span><span class="pun">(</span><span class="str">"Demo"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> node </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Products"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> node1 </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Clothing (Product1 - P66778)"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> node2 </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Accessories (Product2 - P66779)"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> node3 </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Home Decor (Product3 - P66780)"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> node4 </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Electronics (Product4 - P66781)"</span><span class="pun">);</span>
<span class="pln">      node</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">node1</span><span class="pun">);</span>
<span class="pln">      node</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">node2</span><span class="pun">);</span>
<span class="pln">      node</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">node3</span><span class="pun">);</span>
<span class="pln">      node</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">node4</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> one </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Shirt"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> two </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"T-shirt"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> three </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Hoodie"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> four </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Sunglasses"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> five </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Frames"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> six </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Belts"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> seven </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Showpieces & Figurines"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> eight </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Clocks"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> nine </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Wall Shelves"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> ten </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Mobile Accessories"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> eleven </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Smart Wearable Tech"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> twelve </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Health Care Applicances"</span><span class="pun">);</span>
<span class="typ">      DefaultMutableTreeNode</span><span class="pln"> thirteen </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">DefaultMutableTreeNode</span><span class="pun">(</span><span class="str">"Smart Home Automation"</span><span class="pun">);</span>
<span class="pln">      node1</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">one</span><span class="pun">);</span>
<span class="pln">      node1</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">two</span><span class="pun">);</span>
<span class="pln">      node1</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">three</span><span class="pun">);</span>
<span class="pln">      node2</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">four</span><span class="pun">);</span>
<span class="pln">      node2</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">five</span><span class="pun">);</span>
<span class="pln">      node2</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">six</span><span class="pun">);</span>
<span class="pln">      node3</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">seven</span><span class="pun">);</span>
<span class="pln">      node3</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">eight</span><span class="pun">);</span>
<span class="pln">      node3</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">nine</span><span class="pun">);</span>
<span class="pln">      node4</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">ten</span><span class="pun">);</span>
<span class="pln">      node4</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">eleven</span><span class="pun">);</span>
<span class="pln">      node4</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">twelve</span><span class="pun">);</span>
<span class="pln">      node4</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">thirteen</span><span class="pun">);</span>
<span class="typ">      JTree</span><span class="pln"> tree </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">JTree</span><span class="pun">(</span><span class="pln">node</span><span class="pun">);</span>
<span class="kwd">      for</span><span class="pln"> </span><span class="pun">(</span><span class="kwd">int</span><span class="pln"> i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">0</span><span class="pun">;</span><span class="pln"> i </span><span class="pun"><</span><span class="pln"> tree</span><span class="pun">.</span><span class="pln">getRowCount</span><span class="pun">();</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span>
<span class="pln">         tree</span><span class="pun">.</span><span class="pln">expandRow</span><span class="pun">(</span><span class="pln">i</span><span class="pun">);</span>
<span class="pun">      }</span>
<span class="pln">      tree</span><span class="pun">.</span><span class="pln">putClientProperty</span><span class="pun">(</span><span class="str">"JTree.lineStyle"</span><span class="pun">,</span><span class="pln"> </span><span class="str">"Angled"</span><span class="pun">);</span>
<span class="typ">      System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Siblings of node 3's child node eight = "</span><span class="pun">+</span><span class="pln">eight</span><span class="pun">.</span><span class="pln">getSiblingCount</span><span class="pun">());</span>
<span class="pln">      tree</span><span class="pun">.</span><span class="pln">setRowHeight</span><span class="pun">(</span><span class="lit">25</span><span class="pun">);</span>
<span class="pln">      frame</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="pln">tree</span><span class="pun">);</span>
<span class="pln">      frame</span><span class="pun">.</span><span class="pln">setSize</span><span class="pun">(</span><span class="lit">600</span><span class="pun">,</span><span class="lit">450</span><span class="pun">);</span>
<span class="pln">      frame</span><span class="pun">.</span><span class="pln">setVisible</span><span class="pun">(</span><span class="kwd">true</span><span class="pun">);</span>
<span class="pun">   }</span>
<span class="pun">}</span>

The output is as follows displaying this node’s count of siblings on Console −

Output

The following is our JTree −