Examples of java.util.ArrayDeque

java.util.ArrayDeque

Resizable-array implementation of the {@link Deque} interface. Arraydeques have no capacity restrictions; they grow as necessary to support usage. They are not thread-safe; in the absence of external synchronization, they do not support concurrent access by multiple threads. Null elements are prohibited. This class is likely to be faster than {@link Stack} when used as a stack, and faster than {@link LinkedList}when used as a queue.

Most ArrayDeque operations run in amortized constant time. Exceptions include {@link #remove(Object) remove}, {@link #removeFirstOccurrence removeFirstOccurrence}, {@link #removeLastOccurrence removeLastOccurrence}, {@link #contains contains}, {@link #iterator iterator.remove()}, and the bulk operations, all of which run in linear time.

The iterators returned by this class's iterator method are fail-fast: If the deque is modified at any time after the iterator is created, in any way except through the iterator's own remove method, the iterator will generally throw a {@link ConcurrentModificationException}. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.

Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.

This class and its iterator implement all of the optional methods of the {@link Collection} and {@link Iterator} interfaces.

This class is a member of the Java Collections Framework. @author Josh Bloch and Doug Lea @since 1.6 @param < E> the type of elements held in this collection

        assert deque.peekLast().equals("3");
    }


    @Test
    public void contains() throws Exception {
        ArrayDeque deque = create();
        assert deque.contains("3");
        assert deque.contains("4");
        assert !deque.contains("none");
    }

        assert !iterator.hasNext();
    }


    @Test
    public void iteratorRemove() throws Exception {
        ArrayDeque deque = create();
        Iterator iterator = deque.iterator();
        assert iterator.hasNext();
        assert iterator.next().equals("1");
        assert iterator.hasNext();
        assert iterator.next().equals("2");


        assert deque.contains("2");
        iterator.remove();
        assert !deque.contains("2");
    }

     * </p>
     * 
     * @return
     */
    private ArrayDeque<String> create() {
        ArrayDeque deque = new ArrayDeque();


        deque.add("1");
        deque.add("2");
        deque.add("3");
        deque.add("4");


        return deque;
    }

Examples of java.util.ArrayDeque

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