/*
 * 
 * To change the template for this generated file go to
 * Window - Preferences - Java - Code Generation - Code and Comments
 */
package proj2;


/**
 * Interface for unsorted lists.  In an unsorted list,<BR>
 * list elements will stay in the order in which they were added.
 * @author walser
 */
public interface LinkedList<T> {

	/**
	 * Appends the object x to the end of the list
	 * @param x the element to be appended to this list 
	 * @return true
	 */
	public boolean add(T x);
	
	/**
	 * Adds the object x after the idx element
	 * @param x the element to be added to the list
	 * @return true
	 */
	public boolean add(int idx, T x)
	
	/**
	 * Returns the number of elements in this list
	 * @return the number of elements in this list
	 */
	public int size();
	
	/**
	 * Returns the element with the specified position in this list
	 * @param the element to be returned
	 * @return the element at the specified position in this list
	 */
	public T get(T val);
	
	/**
	 * Replaces the old element in this list with
	 * the new object x
	 * @param old element to replace
	 * @param x the element to be stored
	 * @return the previous value of the element 
	 */
	public T set(T old, T x);

    /**
     * Returns an iterator of the elements in this list (in proper sequence).
     * This implementation returns <tt>listIterator(0)</tt>.
     * @return an iterator of the elements in this list (in proper sequence).
     */
    public ListIterator<T> listIterator();

    /**
     * Returns an iterator of the elements in this list (in proper sequence).
     * @param index index of the first element to be returned from the list
     * iterator (by a call to the <tt>next</tt> method).
     * @return a list iterator of the elements in this list (in proper
     * sequence), starting at the specified position in the list.
     */
    public ListIterator<T> listIterator(int index);
        
	
	/**
	 * Removes the first occurence of an object from the list
	 * @param x the element to be removed from this list
	 * @return true if the object was in the list, false otherwise
	 */
	public boolean remove(T x);
		
    /**
     * Tests if this list has no elements.
     *
     * @return  <tt>true</tt> if this list has no elements;
     *          <tt>false</tt> otherwise.
     */
    public boolean isEmpty();

    /**
     * Returns <tt>true</tt> if this list contains the specified element.
     *
     * @param elem element whose presence in this List is to be tested.
     * @return  <code>true</code> if the specified element is present;
     *		<code>false</code> otherwise.
     */
    public boolean contains(T elem);
    

    /**
     * Compares the specified object with this list for equality.
     */
    public boolean equals(Object o);
}