80 lines
1.8 KiB
Java
80 lines
1.8 KiB
Java
import java.util.AbstractQueue;
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import java.util.Iterator;
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import java.util.NoSuchElementException;
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public class LinkedQueue<E> extends AbstractQueue<E> {
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private Node<E> head; // Tête de la file
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private Node<E> tail; // Fin de la file
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private int size; // Taille de la file
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public LinkedQueue() {
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head = null;
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tail = null;
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size = 0;
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}
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@Override
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public boolean offer(E e) {
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if (e == null) {
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throw new NullPointerException("Les éléments null ne sont pas autorisés.");
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}
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Node<E> newNode = new Node<>(e);
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if (tail == null) { // File vide
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head = newNode;
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tail = newNode;
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} else {
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tail.next = newNode;
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tail = newNode;
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}
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size++;
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return true;
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}
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@Override
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public E poll() {
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if (head == null) { // File vide
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return null;
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}
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E element = head.element;
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head = head.next;
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if (head == null) { // La file est maintenant vide
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tail = null;
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}
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size--;
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return element;
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}
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@Override
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public E peek() {
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return (head == null) ? null : head.element;
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}
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@Override
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public Iterator<E> iterator() {
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return new Iterator<E>() {
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private Node<E> current = head;
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@Override
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public boolean hasNext() {
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return current != null;
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}
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@Override
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public E next() {
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if (current == null) {
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throw new NoSuchElementException();
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}
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E element = current.element;
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current = current.next;
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return element;
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}
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};
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}
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@Override
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public int size() {
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return size;
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}
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}
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