Compare List easy

ListComparator

public abstract class ListComparator<B> {
	
	/**
	 * Only compare elements must not change, like id.
	 * 
	 * @param left
	 * @param right
	 * @return
	 */
	protected abstract boolean isEqualsBeans(B left, B right);
	
	/**
	 * Compare elements that must change.
	 * 
	 * @param left
	 * @param right
	 * @return
	 */
	protected abstract boolean isModifyBean(B left, B right);
	
	public List<B> getNewElements(List<B> right, List<B> left) {
		return commonNewDel(right, left);
	}
	
	public List<B> getDelElements(List<B> left, List<B> right) {
		return commonNewDel(left, right);
	}
	
	public List<B> getModElements(List<B> listaBase, List<B> listaComprobacion) {
		List<B> list = new ArrayList<B>();
		for(B b: listaBase){
			if(existAndIsModify(listaComprobacion, b)) {
				list.add(b);
			}
		}
		
		return list;
	}
	
	private boolean existAndIsModify(List<B> list, B b) {
		boolean existe = false;
		boolean existAndIsModify = false;
		Iterator<B> iterator = list.iterator();
		while (iterator.hasNext() && !existe) {
			B bean = iterator.next();
			existe = isEqualsBeans(bean, b);
			if(existe) {
				existAndIsModify = isModifyBean(bean, b);
			}
		}

		return existAndIsModify;
	}
	public List<B> getKeepElements(List<B> left, List<B> right) {
		List<B> list = new ArrayList<B>();
		for(B rightBean: right){
			if(exist(left, rightBean)) {
				list.add(rightBean);
			}
		}
		
		return list;
	}
	
	protected List<B> commonNewDel(List<B> listaBase, List<B> listaComprobacion) {
		List<B> list = new ArrayList<B>();
		for(B b: listaBase){
			if( ! exist(listaComprobacion, b)) {
				list.add(b);
			}
		}
		
		return list;
	}
	
	public boolean isModify(List<B> left, List<B> right) {
		for(B file: left) {
			if( ! exist(right, file)) {
				return true;
			}
		}

		return false;
	}
	
	private boolean exist(List<B> list, B cpv) {
		boolean existe = false;
		Iterator<B> iterator = list.iterator();
		while (iterator.hasNext() && !existe) {
			B bean = iterator.next();
			existe = isEqualsBeans(bean, cpv);
		}

		return existe;
	}

}

ListComparatorTest

public class ListComparatorTest {
	
	protected class MockBean {
		private int id;
		private String name;
		private String description;
		
		public MockBean(int id, String name, String description) {
			super();
			this.id = id;
			this.name = name;
			this.description = description;
		}
		
		public int getId() {
			return id;
		}
		
		public void setId(int id) {
			this.id = id;
		}
		
		public String getName() {
			return name;
		}
		
		public void setName(String name) {
			this.name = name;
		}
		
		public String getDescription() {
			return description;
		}
		
		public void setDescription(String description) {
			this.description = description;
		}
		
	}

	private ListComparator<MockBean> testComparator = null;
	private List<MockBean> listaLeft = null;
	private List<MockBean> listaRight = null;
	
	@Before
	public void init() {
		testComparator = new ListComparator<MockBean>() {
			protected boolean isEqualsBeans(MockBean left, MockBean right) {
				return left.getId() == right.getId();
			}

			@Override
			protected boolean isModifyBean(MockBean left, MockBean right) {
				
				if( ! left.getDescription().equals(right.getDescription())) return true;
				if( ! left.getName().equals(right.getName())) return true;
				
				return false;
			}
		};
		
		listaLeft = new ArrayList<MockBean>();
		listaLeft.add(new MockBean(0, "Cero", "Cero description"));
		listaLeft.add(new MockBean(1, "Uno", "Uno description"));
		listaLeft.add(new MockBean(2, "Dos", "Dos description"));
		listaLeft.add(new MockBean(3, "Tres", "Tres description"));
		
		listaRight = new ArrayList<MockBean>();
		listaRight.add(new MockBean(1, "Uno", "Uno descriptionXXXX"));
		listaRight.add(new MockBean(2, "Dos", "Dos description"));
		listaRight.add(new MockBean(4, "Cuatro", "Cuatro description"));
	}
	
	@Test
	public void testGetNewElements() {
		assertTrue(testComparator.getNewElements(listaRight, listaLeft).size() == 1);
	}
	
	@Test
	public void testGetModElements() {
		assertTrue(testComparator.getModElements(listaRight, listaLeft).size() == 1);
	}

	@Test
	public void testGetDelElements() {
		assertTrue(testComparator.getDelElements(listaLeft, listaRight).size() == 2);
	}

	@Test
	public void testGetKeepElements() {
		assertTrue(testComparator.getKeepElements(listaLeft, listaRight).size() == 2);
	}

	@Test
	public void testIsModify() {
		assertTrue(testComparator.isModify(listaLeft, listaRight));
	}

}