From c7e08524496ef1e5ce84f7373981e9fea652c76c Mon Sep 17 00:00:00 2001 From: Nguyen Nam Thai Date: Tue, 27 Feb 2018 08:55:16 +0700 Subject: [PATCH] Second commit for TDD List implementation --- .../com/baeldung/java/list/CustomList.java | 123 ++++++++---------- .../java/list/CustomListUnitTest.java | 92 +++++++------ 2 files changed, 105 insertions(+), 110 deletions(-) diff --git a/core-java/src/main/java/com/baeldung/java/list/CustomList.java b/core-java/src/main/java/com/baeldung/java/list/CustomList.java index bc1321b1a3..8b91fca32f 100644 --- a/core-java/src/main/java/com/baeldung/java/list/CustomList.java +++ b/core-java/src/main/java/com/baeldung/java/list/CustomList.java @@ -9,6 +9,58 @@ import java.util.ListIterator; public class CustomList implements List { private Object[] internal = {}; + @Override + public boolean isEmpty() { + // the first cycle + // return true; + + // the second cycle + // if (internal.length != 0) { + // return false; + // } else { + // return true; + // } + + // refactoring + return internal.length == 0; + } + + @Override + public int size() { + // the first cycle + // if (isEmpty()) { + // return 0; + // } else { + // return internal.length; + // } + + // refactoring + return internal.length; + } + + @SuppressWarnings("unchecked") + @Override + public E get(int index) { + // the first cycle + // return (E) internal[0]; + + // improvement + return (E) internal[index]; + } + + @Override + public boolean add(E element) { + // the first cycle + // internal = new Object[] { element }; + // return true; + + // the second cycle + Object[] temp = Arrays.copyOf(internal, internal.length + 1); + temp[internal.length] = element; + internal = temp; + return true; + } + @Override public void add(int index, E element) { throw new UnsupportedOperationException(); @@ -44,40 +96,8 @@ public class CustomList implements List { throw new UnsupportedOperationException(); } - @Override - public int size() { - return internal.length; - } - - @Override - public boolean isEmpty() { - return internal.length == 0; - } - - @Override - public boolean add(E element) { - // the first cycle - // internal = new Object[1]; - // internal[0] = element; - // return true; - - Object[] temp = new Object[internal.length + 1]; - System.arraycopy(internal, 0, temp, 0, internal.length); - temp[internal.length] = element; - internal = temp; - return true; - } - - @SuppressWarnings("unchecked") - @Override - public E get(int index) { - return (E) internal[index]; - } - @Override public boolean contains(Object object) { - // return false - for (Object element : internal) { if (object.equals(element)) { return true; @@ -88,14 +108,6 @@ public class CustomList implements List { @Override public boolean containsAll(Collection collection) { - // the first cycle - // for (Object element : collection) { - // if (element.equals(internal[0])) { - // return true; - // } - // } - // return false; - for (Object element : collection) if (!contains(element)) { return false; @@ -118,12 +130,6 @@ public class CustomList implements List { @Override public int indexOf(Object object) { - // the first cycle - // if (object.equals(internal[0])) { - // return 0; - // } - // return -1; - for (int i = 0; i < internal.length; i++) { if (object.equals(internal[i])) { return i; @@ -134,12 +140,6 @@ public class CustomList implements List { @Override public int lastIndexOf(Object object) { - // the first cycle - // if (object.equals(internal[0])) { - // return 0; - // } - // return -1; - for (int i = internal.length - 1; i >= 0; i--) { if (object.equals(internal[i])) { return i; @@ -151,9 +151,6 @@ public class CustomList implements List { @SuppressWarnings("unchecked") @Override public List subList(int fromIndex, int toIndex) { - // the first cycle - // return (List) Arrays.asList(internal); - Object[] temp = new Object[toIndex - fromIndex]; System.arraycopy(internal, fromIndex, temp, 0, temp.length); return (List) Arrays.asList(temp); @@ -167,16 +164,6 @@ public class CustomList implements List { @SuppressWarnings("unchecked") @Override public T[] toArray(T[] array) { - // the first cycle - // array[0] = (T) internal[0]; - // return array; - - // the second cycle - // if (array.length < internal.length) { - // return (T[]) Arrays.copyOf(internal, internal.length, array.getClass()); - // } - // return (T[]) Arrays.copyOf(internal, internal.length, array.getClass()); - if (array.length < internal.length) { return (T[]) Arrays.copyOf(internal, internal.length, array.getClass()); } @@ -209,18 +196,12 @@ public class CustomList implements List { @Override public boolean hasNext() { - // the first cycle - // return true; - return index != internal.length; } @SuppressWarnings("unchecked") @Override public E next() { - // the first cycle - // return (E) CustomList.this.internal[0]; - E element = (E) CustomList.this.internal[index]; index++; return element; diff --git a/core-java/src/test/java/com/baeldung/java/list/CustomListUnitTest.java b/core-java/src/test/java/com/baeldung/java/list/CustomListUnitTest.java index 3ee3195e80..9ea42e88e8 100644 --- a/core-java/src/test/java/com/baeldung/java/list/CustomListUnitTest.java +++ b/core-java/src/test/java/com/baeldung/java/list/CustomListUnitTest.java @@ -14,6 +14,58 @@ import java.util.List; import org.junit.Test; public class CustomListUnitTest { + @Test + public void givenEmptyList_whenIsEmpty_thenTrueIsReturned() { + List list = new CustomList<>(); + + assertTrue(list.isEmpty()); + } + + @Test + public void givenNonEmptyList_whenIsEmpty_thenFalseIsReturned() { + List list = new CustomList<>(); + list.add(null); + + assertFalse(list.isEmpty()); + } + + @Test + public void givenListWithAnElement_whenSize_thenOneIsReturned() { + List list = new CustomList<>(); + list.add(null); + + assertEquals(1, list.size()); + } + + @Test + public void givenListWithAnElement_whenGet_thenThatElementIsReturned() { + List list = new CustomList<>(); + list.add("baeldung"); + Object element = list.get(0); + + assertEquals("baeldung", element); + } + + @Test + public void givenEmptyList_whenElementIsAdded_thenGetReturnsThatElement() { + List list = new CustomList<>(); + boolean succeeded = list.add(null); + + assertTrue(succeeded); + } + + @Test + public void givenListWithAnElement_whenAnotherIsAdded_thenGetReturnsBoth() { + List list = new CustomList<>(); + list.add("baeldung"); + list.add(".com"); + Object element1 = list.get(0); + Object element2 = list.get(1); + + assertEquals("baeldung", element1); + assertEquals(".com", element2); + } + @Test(expected = UnsupportedOperationException.class) public void whenAddToSpecifiedIndex_thenExceptionIsThrown() { new CustomList<>().add(0, null); @@ -64,44 +116,6 @@ public class CustomListUnitTest { list.retainAll(collection); } - @Test - public void givenEmptyList_whenSize_thenZeroIsReturned() { - List list = new CustomList<>(); - - assertEquals(0, list.size()); - } - - @Test - public void givenEmptyList_whenIsEmpty_thenTrueIsReturned() { - List list = new CustomList<>(); - - assertTrue(list.isEmpty()); - } - - @Test - public void givenEmptyList_whenElementIsAdded_thenGetReturnsThatElement() { - List list = new CustomList<>(); - boolean succeeded = list.add("baeldung"); - Object element = list.get(0); - - assertTrue(succeeded); - assertEquals("baeldung", element); - } - - @Test - public void givenListWithAnElement_whenAnotherIsAdded_thenGetReturnsBoth() { - List list = new CustomList<>(); - boolean succeeded1 = list.add("baeldung"); - boolean succeeded2 = list.add(".com"); - Object element1 = list.get(0); - Object element2 = list.get(1); - - assertTrue(succeeded1); - assertTrue(succeeded2); - assertEquals("baeldung", element1); - assertEquals(".com", element2); - } - @Test public void givenEmptyList_whenContains_thenFalseIsReturned() { List list = new CustomList<>(); @@ -271,7 +285,7 @@ public class CustomListUnitTest { } @Test - public void whenIteratorNextIsCalledTwice_thenTheSecondReturnsFalse() { + public void whenIteratorHasNextIsCalledTwice_thenTheSecondReturnsFalse() { List list = new CustomList<>(); list.add("baeldung"); Iterator iterator = list.iterator();