In a coding exercise I am working on, I am trying to generate 25 random integers and insert them into a linked list using a function which sorts them. I understand how to do these tasks separately, but I would like to try to do them as a stream. This is the code I wrote to set this up with a sample list to make sure the insertSorted function works.
class Node<T extends Comparable<T>> {
T data;
Node<T> nextNode;
Node(T data) {
this(data, null);
};
Node(T data, Node<T> nextNode){
this.data = data;
this.nextNode = nextNode;
};
void setNext(Node<T> next){
nextNode = next;
}
}
import java.util.NoSuchElementException;
class SortedList<T extends Comparable<T>> {
private Node<T> firstNode;
private Node<T> lastNode;
private String name;
SortedList(String listName){
name = listName;
firstNode = lastNode = null;
}
void insertSorted(T item){
if(isEmpty()){
lastNode = new Node<T>(item);
firstNode = lastNode;
} else if(firstNode.data.compareTo(item) > 0){
firstNode = new Node<T>(item, firstNode);
}
else {
Node<T> compareNode = firstNode;
while(compareNode.nextNode != null
&& compareNode.nextNode.data.compareTo(item) < 0){
compareNode = compareNode.nextNode;
}
Node<T> itemNode = new Node<T>(item, compareNode.nextNode);
compareNode.setNext(itemNode);
}
}
private boolean isEmpty() { return firstNode == null; }
void print() {
if (isEmpty()){
System.out.printf("Empty %s%n", name);
return;
}
System.out.printf("%s is: ", name);
Node<T> current = firstNode;
while (current != null){
System.out.printf("%s ", current.data);
current = current.nextNode;
}
System.out.println();
}
}
class Main{
public static void main(String[] args){
// sample example
SortedList<Integer> sample = new SortedList<>("sample list");
sample.insertSorted(84);
sample.insertSorted(65);
sample.insertSorted(134);
sample.insertSorted(102);
sample.insertSorted(954);
sample.insertSorted(755);
sample.print();
}
}
I know that I can generate an array of random ints from a stream with code such as this:
int[] arr = new SecureRandom().ints(25, 0, 100).toArray();
How might I contain a random int stream within the SortedList object above using the insertSorted method?
SortedList::insertSorted(T t)
looks like a Consumer<T>
, so you can use stream functions that accept a consumer as an argument, like .forEach(...)
:
new SecureRandom().ints(25, 0, 100)
.boxed()
.forEach( sample::insertSorted );
As @Holger mentions in the comments, .boxed()
is not necessary.
new SecureRandom().ints(25, 0, 100)
.forEach( sample::insertSorted );
I've verified this on Java8 and Java9, so now I'm not sure when it was ever necessary, or what changed when to make it so.