Get Total Number of Leaves of a JTree in Java

Chandu yadav
Updated on 30-Jul-2019 22:30:26

206 Views

To get the total number of leaved of a JTree, apply the getLeafCount() method on the root node. Let’s say our root node is “node”, therefore to count the number of leaves, use −node.getLeafCount()The following is an example to get the total number of leaves of a JTree −package my; import javax.swing.JFrame; import javax.swing.JTree; import javax.swing.tree.DefaultMutableTreeNode; public class SwingDemo {    public static void main(String[] args) throws Exception {       JFrame frame = new JFrame("Demo");       DefaultMutableTreeNode node = new DefaultMutableTreeNode("Website");       DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Videos");       DefaultMutableTreeNode node2 = new ... Read More

Enable Multiple Selections in JFileChooser Dialog with Java

George John
Updated on 30-Jul-2019 22:30:26

169 Views

To enable multiple selections in a JFileChooser dialog, use the setMultiSelectionEnabled() to be TRUE −JFileChooser file = new JFileChooser(); file.setMultiSelectionEnabled(true);The following is an example to enable multiple selections in a JFileChooser Dialog −Examplepackage my; import javax.swing.JFileChooser; public class SwingDemo {    public static void main(String[] args) {       JFileChooser file = new JFileChooser();       file.setMultiSelectionEnabled(true);       file.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);       file.setFileHidingEnabled(false);       if (file.showOpenDialog(null) == JFileChooser.APPROVE_OPTION) {          java.io.File f = file.getSelectedFile();          System.err.println(f.getPath());       }    } }Output

Limit Number of Values in a Field Using MongoDB

Ankith Reddy
Updated on 30-Jul-2019 22:30:26

380 Views

To limit number of values in a field, use $slice operator.Let us first create a collection with documents −> db.numberOfValuesDemo.insertOne({"Values":[100,200,300,900,1000,98]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefb736ef71edecf6a1f6ab") }Display all documents from a collection with the help of find() method −> db.numberOfValuesDemo.find().pretty();Output{    "_id" : ObjectId("5cefb736ef71edecf6a1f6ab"),    "Values" : [       100,       200,       300,       900,       1000,       98    ] }Following is the query to limit number of values in a field using MongoDB −> db.numberOfValuesDemo.find({},{ "Values": { "$slice": 2 } } );Output{ "_id" : ObjectId("5cefb736ef71edecf6a1f6ab"), "Values" : [ 100, 200 ] }

Use Try-With-Resources with JDBC

Smita Kapse
Updated on 30-Jul-2019 22:30:26

5K+ Views

Whenever, we instantiate and use certain objects/resources we should close them explicitly else there is a chance of Resource leak.Generally, we used close resources using the finally block as −Connection con = null; Statement stmt = null; ResultSet rs = null; //Registering the Driver try {    con = DriverManager.getConnection(mysqlUrl, "root", "password");    stmt = con.createStatement(); } catch (SQLException e) {    e.printStackTrace(); }   finally {    try {       rs.close();       stmt.close();       con.close();    } catch(SQLException e) {       e.printStackTrace();    } }From JSE7 onwards the try-with-resources statement is ... Read More

MySQL Query to Return Specific String if Column is Null

Kumar Varma
Updated on 30-Jul-2019 22:30:26

195 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> Name varchar(100)    -> ); Query OK, 0 rows affected (0.85 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.17 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+-------+ | Name ... Read More

Arrange Given Numbers to Form the Biggest Number

Arnab Chakraborty
Updated on 30-Jul-2019 22:30:26

316 Views

Here we will see how to generate the biggest number by rearranging the given numbers. Suppose there are {45, 74, 23} is given, the program will find the largest number, that is 744523. So each digit will not be arranged. but the whole number will be placed to make largest number.To solve this problem, we will use the string sorting. But the comparison logic is different. The comparing function will take two numbers a and b, then concatenate them to form ab and ba. Among them which one is bigger, that is considered.AlgorithmcompareStrings(a, b)begin    ab := concatenate b with ... Read More

NZEC Error in Python

Arjun Thakur
Updated on 30-Jul-2019 22:30:26

926 Views

NZEC is non-zero exit code.Exit codes are codes (number) return by running program to operating system upon either their successfully termination (Exit code 0) or failed termination due to error (Non zero exit code).As python or Java programming language supports exception handling, we can use exception handling using try-catch blocks to catch this error.NZEC error is a runtime error and occurs mostly when negative array index is accesed or the program which we have written is utilizing more memory space than the allocated memory for our program to run.In python Exception class is the super class of all the errors ... Read More

Draw a Border Around an Undecorated JFrame in Java

Samual Sam
Updated on 30-Jul-2019 22:30:26

844 Views

At first, set an undecorated frame −setUndecorated(true);Now draw a border −getRootPane().setBorder (.createMatteBorder(3, 3, 3, 3, Color.ORANGE));The following is an example to draw a border around an undecorated JFrame −Exampleimport java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JLabel; public class SwingDemo extends JFrame {    JLabel label = new JLabel("Welcome!", JLabel.CENTER);    public SwingDemo() {       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       setSize(new Dimension(500, 300));       add(label, BorderLayout.CENTER);       setUndecorated(true);       getRootPane().setBorder(          BorderFactory.createMatteBorder(3, 3, 3, 3, Color.ORANGE));       setVisible(true);    }    public static void main(String[] args) {       new SwingDemo();    } }Output

Suppress Android Notification on Lock Screen

Anvi Jain
Updated on 30-Jul-2019 22:30:26

478 Views

This example demonstrate about How to suppress Android notification on lock screen but let it be in notification areaStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml.     Step 3 − Add the following code to res/layout/custom_notification_layout.xml.             Step 4 − Add the following code to src/MainActivity.package app.tutorialspoint.com.notifyme ; import android.app.KeyguardManager ; import android.app.NotificationChannel ; import android.app.NotificationManager ; import android.content.Context ; import android.os.Bundle ; import android.support.v4.app.NotificationCompat ; import ... Read More

Get Documents Expired Before Today in MongoDB

Smita Kapse
Updated on 30-Jul-2019 22:30:26

341 Views

You can use $lte operator along with Date() for this. Let us first create a collection with documents. Here, we have set the date 2019-05-11, which is the current date −> db.getDocumentsExpiredDemo.insertOne({"ArrivalDate":new ISODate("2019-05-11")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd563b17924bb85b3f4893b") } > db.getDocumentsExpiredDemo.insertOne({"ArrivalDate":new ISODate("2019-01-01")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd563bf7924bb85b3f4893c") } > db.getDocumentsExpiredDemo.insertOne({"ArrivalDate":new ISODate("2019-05-10")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd563ca7924bb85b3f4893d") } > db.getDocumentsExpiredDemo.insertOne({"ArrivalDate":new ISODate("2019-02-01")}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd563e77924bb85b3f4893e") }Following is the query to display all documents from a collection with the help of find() method −> db.getDocumentsExpiredDemo.find().pretty();This ... Read More

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