abstractlinear.java

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// An abstract implementation of LIFO/FIFO structures.
// (c) 1998,2001 duane a. bailey

package structure;
/**
 * An abstract implemtation of linear data structures. Linear structures have 
 * completely determined  add and remove methods.  
 * Linear structures are often used to store the the state of a recursively
 * solved problem and stacks and queues are classic examples of such structures.
 *
 * @version $Id: Linear.java,v 4.0 2000/12/27 21:21:47 bailey Exp bailey $
 * @author, 2001 duane a. bailey
 * @see structure.Stack
 * @see structure.Queue
 */
abstract public class AbstractLinear extends AbstractStructure
    implements Linear
{
    /**
     * Determine if there are elements within the linear.
     *
     * @post return true iff the linear structure is empty
     * @return true if the linear structure is empty; false otherwise
     */
    public boolean empty()
    {
	return isEmpty();
    }

    /**
     * Removes value from the linear structure.
     * Not implemented (by default) for linear classes.
     *
     * @param value value matching the value to be removed
     * @pre value is non-null
     * @post value is removed from linear structure, if it was there
     * @return returns the value that was replaced, or null if none.
     */
    public Object remove(Object o)
    {
	Assert.fail("Method not implemented.");
	// never reaches this statement:
	return null;
    }
}