/** * Method to retain a Collection of elements (and remove all others). * * @param c The collection to retain * @return Whether they were retained successfully. */ public synchronized boolean retainAll(java.util.Collection c) { boolean success = delegate.retainAll(c); if (success) { makeDirty(); if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive()) { ownerOP.getExecutionContext().processNontransactionalUpdate(); } } return success; }
public void methodsOfPQ() { PriorityQueue<Integer> pq = new PriorityQueue<Integer>(); // Default Constructor: // Queue<Integer> pq = new PriorityQueue<Integer>(); pq.add(10); pq.add(30); pq.add(50); pq.add(40); pq.add(20); System.out.println(pq); // [10, 20, 50, 40, 30] pq.offer(75); // add element randomly anywhere System.out.println(pq); // [10, 20, 50, 40, 30, 75] System.out.println(pq.peek()); // 10 | return head of queue and don't touch pq System.out.println(pq); // [10, 20, 50, 40, 30, 75] System.out.println(pq.poll()); // 10 | return head and also removes head from pq System.out.println(pq); // [20, 50, 40, 30, 75] System.out.println(pq.element()); // 20 | same as peek but throw exception if pq is empty System.out.println(pq); // [20, 50, 40, 30, 75] pq.remove(); // 20 | same as poll but throw exception when queue is empty System.out.println(pq); // [50, 40, 30, 75] List<Integer> ls = new ArrayList<Integer>(); ls.add(1000); ls.add(2000); pq.addAll(ls); System.out.println(pq); // [30, 40, 50, 75, 1000, 2000] pq.removeAll(ls); System.out.println(pq); // [30, 40, 50, 75] ls.clear(); // empty ls ls.add(101); ls.add(102); pq.addAll(ls); pq.retainAll(ls); // all element will be removed except ls System.out.println(pq); // [101, 102] System.out.println(pq.containsAll(ls)); // true System.out.println("********************************************"); // Queue<String> q=new PriorityQueue<String>(); }