GenericList.java

package Fall0811;
import java.util.Iterator;

public class GenericList<E> implements Iterable<E>{
 // class constant
    private static final int DEFAULT_CAP = 10;
 
    // instance variables
    protected E[] container; // the array is NOT the list
    private int listSize;
    
    public Iterator<E> iterator(){
        return new GenListIterator();
    }
    
    // inner class
    private class GenListIterator implements Iterator<E>{
        private int indexOfNextElement;
        private boolean okToRemove;
        
        private GenListIterator(){
            indexOfNextElement = 0;
            okToRemove = false;
        }
        
        public boolean hasNext(){
            return indexOfNextElement < size();
        }
        
        public E next(){
            assert hasNext();
            okToRemove = true;
            indexOfNextElement++;
            return container[indexOfNextElement - 1];
        }
        
        public void remove(){
            assert okToRemove;
            okToRemove = false;
            indexOfNextElement--;
            GenericList.this.remove(indexOfNextElement);
        }
        
    }
    
    public boolean equals(Object obj){
        assert this != null;
        if(obj == null)
            return false;
        else if (this == obj)
            return true;
        else if( this.getClass() != obj.getClass() )
            return false;
        else{
            // obj is a non null GenericList
            GenericList list = (GenericList)obj;
            if( list.size() != size() )
                return false;
            for(int i = 0; i < size(); i++)
                if( (get(i) == null && list.get(i) != null) || !get(i).equals(list.get(i)) )
                    return false;
            return true;
        }
        
            
    }
    

    // creates an empty IntList
    public GenericList(){
        this(DEFAULT_CAP);
    }

    // pre: initialCap >= 0
    public GenericList(int initialCap){
        assert initialCap >= 0 : "failed precondition";
        container = (E[])(new Object[initialCap]);
        listSize = 0;        
    }
    
    public void insertAll(int pos, GenericList<E> otherList){
        
        for(int i = 0; i < otherList.listSize; i++){
            this.insert(pos + i, otherList.container[i]);
        }
    }
    
    // pre: 0 <= pos < size()
    public E remove(int pos){
        E result = container[pos];
        listSize--;
        for(int index = pos; index < size(); index++){
            container[index] = container[index + 1];
        }
        container[listSize] = null;
        return result;
    }
    
    // pre: 0 <= pos <= size()
    public void insert(int pos, E element){
        assert 0 <= pos && pos <= size();
        if( size() == container.length )
            resize();
        for(int index = size(); index > pos; index--){
            assert index > 0;
            container[index] = container[index - 1];
        }
        container[pos] = element;
        listSize++;
    }
    
    // get size of list
    public int size(){
        return listSize;
    }
    
    // access elements
    // pre: 0 <= position < size()
    public E get(int position){
        assert 0 <= position && position < size();
        return container[position];
    }
    
    // pre: none
    public void add(E element){    
        insert(size(), element);
    }

    private void resize() {
        E[] temp = (E[])(new Object[container.length * 2 + 1]);
        System.arraycopy(container, 0, temp, 0, size());
        container = temp;
    }
    
    public String toString(){
        StringBuffer result = new StringBuffer("[");
        final int LIMIT = size() - 1;
        for(int i = 0; i < LIMIT; i++){
            if( this == this.get(i) )
                result.append("this list");
            else{
                result.append(get(i));
            }
            result.append(", ");
        }
        if( size() != 0)
            result.append(get(size() - 1));
        result.append("]");
        return result.toString();
    }
   
}