data-structures/java/SList/List.java

/** List ADT */
public interface List<T> {
    /** Remove all contents from the list, so it is once again empty. Client is responsible for reaclaiming storage used by the list elements. */
    public void clear();

    /** Insert an element at the current location. The client must ensure that the list's capacity is not exceeded.
	@param item The element to be inserted. */
    public void insert(T item);

    /** Append an element at the end of the list. The client must ensure that the list's capacity is not exceeded.
	@param item The element to be appended. */
    public void append(T item);

    /** Remove and return the current element.
	@return The element that was removed. */
    public T remove();

    /** Set the current position to the start of the list */
    public void moveToStart();

    /** Set the current position to the end of the list */
    public void moveToEnd();
    /** Move the current position one step left. No change if already at beginning. */
    public void prev();

    /** Move the current position one step right. No change if already at end. */
    public void next();

    /** @return The number of elements in the list. */
    public int length();

    /** @return The position of the current element. */
    public int currPos();

    /** Set current position.
	@param pos The position to make current. */
    public void moveToPos(int pos);

    /** @return The current element. */
    public T getValue();

    /** @return True if k is in the list L, false otherwise */
    public static boolean find(List<Integer> L, int k) {
	for (L.moveToStart(); L.currPos() < L.length(); L.next()) {
	    if (k == L.getValue()) return true; // Found k
	}
	return false; // k not found
    }
}