A ListIterator can be used to traverse the elements in the forward direction as well as the reverse direction in the List Collection. So the ListIterator is only valid for classes such as LinkedList, ArrayList etc.The method hasPrevious( ) in ListIterator returns true if there are more elements in the List while traversing in the reverse direction and false otherwise. The method previous( ) returns the previous element in the List and reduces the cursor position backward.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.ListIterator; public class Demo {    public static void main(String[] args) ... Read More

The NavigableMap pollLastEntry() method remove and returns a key-value mapping associated with the greatest key in this map.Let us first create a NavigableMap and add some elements to it −NavigableMap n = new TreeMap(); n.put(5, "Tom"); n.put(9, "John"); n.put(14, "Jamie"); n.put(1, "Tim"); n.put(4, "Jackie"); n.put(15, "Kurt"); n.put(19, "Tiger"); n.put(24, "Jacob");Now, use the following method −n.pollLastEntry();The following is an example to implement the pollLastEntry() method −Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       NavigableMap n = new TreeMap();       n.put(5, "Tom");       n.put(9, "John");       n.put(14, ... Read More

The floorEntry() NavigableMap method returns a key-value mapping associated with the greatest key less than or equal to the given keyThe following is an example to implement floorEntry() method −Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {       NavigableMap n = new TreeMap();       n.put(5, "Tom");       n.put(9, "John");       n.put(14, "Jamie");       n.put(1, "Tim");       n.put(4, "Jackie");       n.put(15, "Kurt");       n.put(19, "Tiger");       n.put(24, "Jacob");       System.out.println("NavigableMap elements..."+n);       System.out.println("Floor Entry = "+n.floorEntry(5));    } }OutputNavigableMap elements... {1=Tim, 4=Jackie, 5=Tom, 9=John, 14=Jamie, 15=Kurt, 19=Tiger, 24=Jacob} Floor Entry 5=Tom

Use Iterator and the values() method to iterate through the values of TreeMap.Let us first create a TreeMap and add some elements −TreeMap m = new TreeMap(); m.put(1, "PHP"); m.put(2, "jQuery"); m.put(3, "JavaScript"); m.put(4, "Ruby"); m.put(5, "Java"); m.put(6, "AngularJS"); m.put(7, "ExpressJS");Iterate through the values −Collection res = m.values(); Iterator i = res.iterator(); while (i.hasNext()) {    System.out.println(i.next()); }The following is the complete example to iterate through the values −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]) {       TreeMap m = new TreeMap();       m.put(1, "PHP");       m.put(2, "jQuery"); ... Read More

To get Tail Map from TreeMap, use the tailMap() method. It gets a part or view of the map whose keys are greater than equal to the key set as a parameter.Let us first create a TreeMap −TreeMap m = new TreeMap();Now, we will add some elements −m.put(1, "PHP"); m.put(2, "jQuery"); m.put(3, "JavaScript"); m.put(4, "Ruby"); m.put(5, "Java"); m.put(6, "AngularJS"); m.put(7, "ExpressJS");Get the Tail Map −m.tailMap(4)The following is an example to get Tail Map from TreeMap in Java −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeMap m = new TreeMap();     ... Read More

A ListIterator can be used to traverse the elements in the forward direction as well as the reverse direction in the List Collection. So the ListIterator is only valid for classes such as LinkedList, ArrayList etc.The method hasNext( ) in ListIterator returns true if there are more elements in the List and false otherwise. The method next( ) returns the next element in the List and advances the cursor position.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.ListIterator; public class Demo {    public static void main(String[] args) {       ArrayList aList = ... Read More

A collection in Java provides an architecture to handle a group of objects. The different classes in the Java Collection Framework are ArrayList, LinkedList, HashSet, Vector etc.An Iterator can be used to iterate through a Collection and a program that demonstrates this using ArrayList is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.Iterator; public class Demo {    public static void main(String[] args) {       ArrayList aList = new ArrayList();       aList.add("John");       aList.add("Peter");       aList.add("Harry");       aList.add("James");       aList.add("Arthur");       System.out.println("The ArrayList elements are: "); ... Read More

To detect current device with iOS/Swift we can use UserInterfaceIdiom. It is an enum in swift, which tells which device is being used.The interface idiom provides multiple values in it’s enum which are.case unspecified @available(iOS 3.2, *) case phone // iPhone and iPod touch style UI @available(iOS 3.2, *) case pad // iPad style UI @available(iOS 9.0, *) case tv // Apple TV style UI @available(iOS 9.0, *) case carPlay // CarPlay style UIIn swift interfaceIdiom can be used in the following way:print(UIDevice.current.userInterfaceIdiom) if UIDevice.current.userInterfaceIdiom == .phone { print("running on iPhone") }When we run the above code ... Read More

To detect a shake gesture in iOS UIKit provides three different methods, let’s see them one by one.Method 1 − When the shake gesture begins.override func motionBegan(_ motion: UIEvent.EventSubtype, with event: UIEvent?) { // code you want to implement }Method 2 − When the shake gesture ends.override func motionEnded(_ motion: UIEvent.EventSubtype, with event: UIEvent?) { // Code you want to implement. }Method 3 − when the shake gesture is cancelled.override func motionCancelled(_ motion: UIEvent.EventSubtype, with event: UIEvent?) { // code you want to implement. }Now let’s add some code in our motionBegan method, override func motionBegan(_ motion: UIEvent.EventSubtype, with event: ... Read More

To subtract hours from a date in swift we need to create a date first. Once that date is created we have to subtract hours from that, though swift does not provide a way to subtract date or time, but it provides us a way to add date or date component in negative value. In this example we’ll see how we can achieve the same.Let’s create a date first, let it be today, let today = Date()Now to modify this date we’ll use the add function with negative value, let modifiedDate = Calendar.current.date(byAdding: .hour, value: -2, to: today)!Now to see ... Read More