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AIMA-Java Core Algorithms from the book Artificial Intelligence a Modern Approach 3rd Ed.

There is a newer version: 3.0.0

package aima.core.util.datastructure;

/**
 * Artificial Intelligence A Modern Approach (3rd Edition): pg 79.

 * 

 * The operations on a queue are as follows:

 * 
 * EMPTY?(queue) returns true only if there are no elements in the queue
 * POP(queue) removes the first element of the queue and returns it.
 * INSERT(element, queue) inserts an element and returns the resulting
 * queue.
 * 
 * Note: This extends the java.util.Queue collections interface in order to take
 * advantage of pre-existing implementations. The intent of this interface is
 * purely to provide an interface to Queues that corresponds to what is
 * described in AIMA3e.
 * 
 * @author Ravi Mohan
 * @author Ciaran O'Reilly
 * 
 */
public interface Queue extends java.util.Queue {
	/**
	 * EMPTY?(queue)
	 * 
	 * @return true only if there are no elements on the queue.
	 */
	boolean isEmpty();

	/**
	 * POP(queue)
	 * 
	 * @return the first element of the queue.
	 */
	E pop();

	/**
	 * INSERT(element, queue)
	 * 
	 * @param element
	 *            to be inserted in the queue.
	 * @return the resulting queue with the element inserted. null is returned
	 *         if the element could not be inserted.
	 */
	Queue insert(E element);
}