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Merge pull request #3739 from nguyennamthai/BAEL-1537

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Second commit for TDD List implementation
This commit is contained in:
Tom Hombergs 2018-02-28 19:59:17 +01:00 committed by GitHub
commit 5c181c4b72
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 105 additions and 110 deletions
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123
core-java/src/main/java/com/baeldung/java/list/CustomList.java
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@ -9,6 +9,58 @@ import java.util.ListIterator;
public class CustomList<E> implements List<E> { public class CustomList<E> implements List<E> {
private Object[] internal = {}; 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 @Override
public void add(int index, E element) { public void add(int index, E element) {
throw new UnsupportedOperationException(); throw new UnsupportedOperationException();
@ -44,40 +96,8 @@ public class CustomList<E> implements List<E> {
throw new UnsupportedOperationException(); 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 @Override
public boolean contains(Object object) { public boolean contains(Object object) {
// return false
for (Object element : internal) { for (Object element : internal) {
if (object.equals(element)) { if (object.equals(element)) {
return true; return true;
@ -88,14 +108,6 @@ public class CustomList<E> implements List<E> {
@Override @Override
public boolean containsAll(Collection<?> collection) { 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) for (Object element : collection)
if (!contains(element)) { if (!contains(element)) {
return false; return false;
@ -118,12 +130,6 @@ public class CustomList<E> implements List<E> {
@Override @Override
public int indexOf(Object object) { 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++) { for (int i = 0; i < internal.length; i++) {
if (object.equals(internal[i])) { if (object.equals(internal[i])) {
return i; return i;
@ -134,12 +140,6 @@ public class CustomList<E> implements List<E> {
@Override @Override
public int lastIndexOf(Object object) { 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--) { for (int i = internal.length - 1; i >= 0; i--) {
if (object.equals(internal[i])) { if (object.equals(internal[i])) {
return i; return i;
@ -151,9 +151,6 @@ public class CustomList<E> implements List<E> {
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
@Override @Override
public List<E> subList(int fromIndex, int toIndex) { public List<E> subList(int fromIndex, int toIndex) {
// the first cycle
// return (List<E>) Arrays.asList(internal);
Object[] temp = new Object[toIndex - fromIndex]; Object[] temp = new Object[toIndex - fromIndex];
System.arraycopy(internal, fromIndex, temp, 0, temp.length); System.arraycopy(internal, fromIndex, temp, 0, temp.length);
return (List<E>) Arrays.asList(temp); return (List<E>) Arrays.asList(temp);
@ -167,16 +164,6 @@ public class CustomList<E> implements List<E> {
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
@Override @Override
public <T> T[] toArray(T[] array) { public <T> 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) { if (array.length < internal.length) {
return (T[]) Arrays.copyOf(internal, internal.length, array.getClass()); return (T[]) Arrays.copyOf(internal, internal.length, array.getClass());
} }
@ -209,18 +196,12 @@ public class CustomList<E> implements List<E> {
@Override @Override
public boolean hasNext() { public boolean hasNext() {
// the first cycle
// return true;
return index != internal.length; return index != internal.length;
} }
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
@Override @Override
public E next() { public E next() {
// the first cycle
// return (E) CustomList.this.internal[0];
E element = (E) CustomList.this.internal[index]; E element = (E) CustomList.this.internal[index];
index++; index++;
return element; return element;

92
core-java/src/test/java/com/baeldung/java/list/CustomListUnitTest.java
View File

@ -14,6 +14,58 @@ import java.util.List;
import org.junit.Test; import org.junit.Test;
public class CustomListUnitTest { public class CustomListUnitTest {
@Test
public void givenEmptyList_whenIsEmpty_thenTrueIsReturned() {
List<Object> list = new CustomList<>();
assertTrue(list.isEmpty());
}
@Test
public void givenNonEmptyList_whenIsEmpty_thenFalseIsReturned() {
List<Object> list = new CustomList<>();
list.add(null);
assertFalse(list.isEmpty());
}
@Test
public void givenListWithAnElement_whenSize_thenOneIsReturned() {
List<Object> list = new CustomList<>();
list.add(null);
assertEquals(1, list.size());
}
@Test
public void givenListWithAnElement_whenGet_thenThatElementIsReturned() {
List<Object> list = new CustomList<>();
list.add("baeldung");
Object element = list.get(0);
assertEquals("baeldung", element);
}
@Test
public void givenEmptyList_whenElementIsAdded_thenGetReturnsThatElement() {
List<Object> list = new CustomList<>();
boolean succeeded = list.add(null);
assertTrue(succeeded);
}
@Test
public void givenListWithAnElement_whenAnotherIsAdded_thenGetReturnsBoth() {
List<Object> 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) @Test(expected = UnsupportedOperationException.class)
public void whenAddToSpecifiedIndex_thenExceptionIsThrown() { public void whenAddToSpecifiedIndex_thenExceptionIsThrown() {
new CustomList<>().add(0, null); new CustomList<>().add(0, null);
@ -64,44 +116,6 @@ public class CustomListUnitTest {
list.retainAll(collection); list.retainAll(collection);
} }
@Test
public void givenEmptyList_whenSize_thenZeroIsReturned() {
List<Object> list = new CustomList<>();
assertEquals(0, list.size());
}
@Test
public void givenEmptyList_whenIsEmpty_thenTrueIsReturned() {
List<Object> list = new CustomList<>();
assertTrue(list.isEmpty());
}
@Test
public void givenEmptyList_whenElementIsAdded_thenGetReturnsThatElement() {
List<Object> 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<Object> 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 @Test
public void givenEmptyList_whenContains_thenFalseIsReturned() { public void givenEmptyList_whenContains_thenFalseIsReturned() {
List<Object> list = new CustomList<>(); List<Object> list = new CustomList<>();
@ -271,7 +285,7 @@ public class CustomListUnitTest {
} }
@Test @Test
public void whenIteratorNextIsCalledTwice_thenTheSecondReturnsFalse() { public void whenIteratorHasNextIsCalledTwice_thenTheSecondReturnsFalse() {
List<Object> list = new CustomList<>(); List<Object> list = new CustomList<>();
list.add("baeldung"); list.add("baeldung");
Iterator<Object> iterator = list.iterator(); Iterator<Object> iterator = list.iterator();