// CSE 143, Winter 2011, Marty Stepp
// This class captures common code shared by both the ArrayList and LinkedList.
// An abstract class is a good way to provide a partially implemented class, or
// a partial implementation of an interface.  Notice that the header of this
// class claims to implement the List interface, but the file doesn't
// write all of the methods.  Java allows this file to compile because it knows
// the abstract class must be extended to complete it.  If a subclass of
// AbstractList doesn't implement all the rest of the List
// interface's methods, that subclass will not compile.  

public abstract class AbstractList<E> implements List<E> {
    // Adds the given value to the end of the list.
    // If necessary, resizes the array to fit the value.
    public void add(E value) {
        // just call the other add method (to remove redundancy)
        add(size(), value);
    }

    // Returns true if the given value is found in this list.
    public boolean contains(E value) {
        return indexOf(value) >= 0;
    }
    
    // Returns true if the list does not contain any elements.
    public boolean isEmpty() {
        return size() == 0;   // "boolean zen"
    }
}