[데이터 구조] [2] 배열 이 실현 하 는 선형 표 (선형 표 의 순서 저장 구조)

public class ArrayListTest {

	private Object[] elements;//    

	private  static final Object[] EMPTY_ARRAY = {};//   

	/**
	 *        
	 */
	public ArrayListTest(){
	    this.elements = EMPTY_ARRAY;
	}
	

	/**
	 *          
	 */
	public void add(Object element){
	    //      ,                    
	    Object[] newArr = new Object[elements.length + 1];
	    //    
	    for(int i = 0; i< elements.length; i++){
	    	newArr[i] = elements[i];
	    }
	    //          
	    newArr[elements.length] = element;
	    //            
	    this.elements = newArr;
	}
	
	/**
	 *            
	 */
	public void insert(int index, Object element){
	    //        
	    if(index < 0 || index >= elements.length){
	    	throw new RuntimeException("      ");
	    }
	    //      ,                    
	    Object[] newArr = new Object[elements.length + 1];
	    //    
	    for(int i = 0; i< newArr.length; i++){
		if(i < index){
	       	    //index       
		    newArr[i] = elements[i];
		}else if(index == i){
		    //index       element
	       	    newArr[i] = element;
		}else{
		    //index             -1   
		    newArr[i] = elements[i - 1];
		}
	    }
	    //            
	    this.elements = newArr;
	}
	
	/**
	 *         
	 */
	public Object get(int index){
	    //        
	    if(index < 0 || index >= elements.length){
		throw new RuntimeException("      ");
	    }
	    return elements[index];
	}
	
	/**
	 *         
	 */
	public void delete(int index){
	    //        
	    if(index < 0 || index >= elements.length){
		throw new RuntimeException("      ");
	    }
	    //      ,                    
	    Object[] newArr = new Object[elements.length - 1];
	    //    
	    for(int i = 0; i< newArr.length; i++){
	    	if(i < index){
		    //index       
		    newArr[i] = elements[i];
		}else{
		    //  index      
		    newArr[i] = elements[i + 1];
		}
	    }
	    //            
	    elements = newArr;
	}
	
	/**
	 *         
	 */
	public void deleteElement(Object object){
	    Integer index = null;
	    //           object     
	    for(int i = 0; i< elements.length; i++){
		if(object.equals(elements[i])){
		    index = i;
		    break;
		}
	    }
	    if(index != null){
		delete(index);
	    }else{
		System.out.println("         ");
	    }
	}
	
	/**
         *         
         */
	public int size(){
	    return elements.length;
	}
	
        /**
         *           
         */
        public boolean isEmpty(){
            return elements.length == 0;
        }
    
        /**
         *     
         */
	public void show(ArrayListTest arrayTest){
	    System.out.println(Arrays.toString(arrayTest.elements));
	}
	
	public static void main(String[] args) {
	    ArrayListTest arrays = new ArrayListTest();
	    arrays.add(1);
	    arrays.add(2);
	    arrays.add(3);
	    arrays.show(arrays);//[1, 2, 3]
		
	    arrays.insert(1, 0);
	    arrays.show(arrays);//[1, 0, 2, 3]
		
	    Object arrObj = arrays.get(1);
	    System.out.println(arrObj);//0
		
	    arrays.delete(2);
	    arrays.show(arrays);//[1, 0, 3]
		
	    arrays.deleteElement(3);
	    arrays.show(arrays);//[1, 0]
		
	    System.out.println(arrays.size());//2
	    System.out.println(arrays.isEmpty());//false

	}
}