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Queue Blocking - Need More Information

This question is related to one of my previous questions.

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Here, the nature of blocking is mentioned as an advantage.

I tried to develop simple code to demonstrate a blocking nature, but I was stuck. I just tried making BlockingQueue4 in size and tried to add 5 elements and got it java.lang.IllegalStateException. Can someone show me some example code to block nature BlockingQueue?

public static void main(String[] args) {
    BlockingQueue<String> bq = new LinkedBlockingQueue<String>(4);

    try {
        bq.offer("A");
        bq.offer("B");
        bq.offer("C");
        bq.offer("D");
        bq.offer("E");

        System.out.println("1 = " + bq.take());
        System.out.println("2 = " + bq.take());
        System.out.println("3 = " + bq.take());
        System.out.println("4 = " + bq.take());
        System.out.println("5 = " + bq.take());
        System.out.println("6 = " + bq.take());
    } catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
}

. 5 4. 4 (A, B, C, D). take(). "E" , System.out.println("1 = " + bq.take());? ?

+5
4

add, offer, put? , add, , IllegalStateException; , , , put ( take .)

: .

" E , take() ?" , , take(), E. .

, offer() put(), put("E") . ? , - . , BlockingQueues . ( , ), .

:

public static void main(String[] args) {
    final BlockingQueue<String> bq = new LinkedBlockingQueue<String>(4);

    Runnable producer = new Runnable() {
        public void run() {
            try {
                bq.put("A");
                bq.put("B");
                bq.put("C");
                bq.put("D");
                bq.put("E");
            } catch (InterruptedException ex) {
                Thread.currentThread().interrupt(); 
            }
        }
    };
    Runnable consumer = new Runnable() {
        public void run() {
            try {
                System.out.println("1 = " + bq.take());
                System.out.println("2 = " + bq.take());
                System.out.println("3 = " + bq.take());
                System.out.println("4 = " + bq.take());
                System.out.println("5 = " + bq.take());
                System.out.println("6 = " + bq.take());
            } catch (InterruptedException ex) {
                Thread.currentThread().interrupt();
            }
        }
    };
    new Thread(producer).start();
    new Thread(consumer).start();
}

put("E") , , "A" . take() - , .

+11

mmyers : P (+1)
, , !

: put() , put() , . , .

==== ======

a BlockingQueue - , .

" " , - , , , , block (), - .

ArrayBlockingQueue
DelayQueue
LinkedBlockingQueue
PriorityBlockingQueue
SynchronousQueue

http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/BlockingQueue.html

//your main collection
LinkedBlockingQueue<Integer> lbq = new LinkedBlockingQueue<Integer>();

//Add your values
lbq.put(100);
lbq.put(200);

//take() will actually remove the first value from the collection, 
//or block if no value exists yet.
//you will either have to interrupt the blocking, 
//or insert something into the queue for the program execution to continue

int currVal = 0;
try {
    currVal = lbq.take();
} catch (InterruptedException e) {
    e.printStackTrace();
}

>

+2

: - , , , , , ( "E" ), false, . ( "E" ), , . . , , .

+1

,

 /**
 * Inserts the specified element into this queue if it is possible to do
 * so immediately without violating capacity restrictions, returning
 * {@code true} upon success and throwing an
 * {@code IllegalStateException} if no space is currently available.
 * When using a capacity-restricted queue, it is generally preferable to
 * use {@link #offer(Object) offer}.
 *
 * @param e the element to add
 * @return {@code true} (as specified by {@link Collection#add})
 * @throws IllegalStateException if the element cannot be added at this
 *         time due to capacity restrictions
 * @throws ClassCastException if the class of the specified element
 *         prevents it from being added to this queue
 * @throws NullPointerException if the specified element is null
 * @throws IllegalArgumentException if some property of the specified
 *         element prevents it from being added to this queue
 */
boolean add(E e);

/**
 * Inserts the specified element into this queue if it is possible to do
 * so immediately without violating capacity restrictions, returning
 * {@code true} upon success and {@code false} if no space is currently
 * available.  When using a capacity-restricted queue, this method is
 * generally preferable to {@link #add}, which can fail to insert an
 * element only by throwing an exception.
 *
 * @param e the element to add
 * @return {@code true} if the element was added to this queue, else
 *         {@code false}
 * @throws ClassCastException if the class of the specified element
 *         prevents it from being added to this queue
 * @throws NullPointerException if the specified element is null
 * @throws IllegalArgumentException if some property of the specified
 *         element prevents it from being added to this queue
 */
boolean offer(E e);

/**
 * Inserts the specified element into this queue, waiting if necessary
 * for space to become available.
 *
 * @param e the element to add
 * @throws InterruptedException if interrupted while waiting
 * @throws ClassCastException if the class of the specified element
 *         prevents it from being added to this queue
 * @throws NullPointerException if the specified element is null
 * @throws IllegalArgumentException if some property of the specified
 *         element prevents it from being added to this queue
 */
void put(E e) throws InterruptedException;

/**
 * Inserts the specified element into this queue, waiting up to the
 * specified wait time if necessary for space to become available.
 *
 * @param e the element to add
 * @param timeout how long to wait before giving up, in units of
 *        {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the
 *        {@code timeout} parameter
 * @return {@code true} if successful, or {@code false} if
 *         the specified waiting time elapses before space is available
 * @throws InterruptedException if interrupted while waiting
 * @throws ClassCastException if the class of the specified element
 *         prevents it from being added to this queue
 * @throws NullPointerException if the specified element is null
 * @throws IllegalArgumentException if some property of the specified
 *         element prevents it from being added to this queue
 */
boolean offer(E e, long timeout, TimeUnit unit)
    throws InterruptedException;

/**
 * Retrieves and removes the head of this queue, waiting if necessary
 * until an element becomes available.
 *
 * @return the head of this queue
 * @throws InterruptedException if interrupted while waiting
 */
E take() throws InterruptedException;

/**
 * Retrieves and removes the head of this queue, waiting up to the
 * specified wait time if necessary for an element to become available.
 *
 * @param timeout how long to wait before giving up, in units of
 *        {@code unit}
 * @param unit a {@code TimeUnit} determining how to interpret the
 *        {@code timeout} parameter
 * @return the head of this queue, or {@code null} if the
 *         specified waiting time elapses before an element is available
 * @throws InterruptedException if interrupted while waiting
 */
E poll(long timeout, TimeUnit unit)
    throws InterruptedException;
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