Add support for methods added to interface List in JDK 21

centic9 · Apr 22, 2024 · a454a0f · a454a0f
1 parent f2a6a15
commit a454a0f
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Showing 4 changed files with 80 additions and 1 deletion.
diff --git a/src/main/java/org/dstadler/commons/collections/ObjectAccessorList.java b/src/main/java/org/dstadler/commons/collections/ObjectAccessorList.java
@@ -2,6 +2,7 @@
 
 import java.util.Iterator;
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -75,4 +76,22 @@ public R next() {
     public void forEach(Consumer<? super R> action) {
         original.forEach(e -> action.accept(accessor.apply(e)));
     }
+
+	@Override
+	public R getFirst() {
+		if (original.isEmpty()) {
+			throw new NoSuchElementException();
+		} else {
+			return accessor.apply(original.get(0));
+		}
+	}
+
+	@Override
+	public R getLast() {
+		if (original.isEmpty()) {
+			throw new NoSuchElementException();
+		} else {
+			return accessor.apply(original.get(original.size() - 1));
+		}
+	}
 }
diff --git a/src/main/java/org/dstadler/commons/collections/UnsupportedList.java b/src/main/java/org/dstadler/commons/collections/UnsupportedList.java
@@ -61,4 +61,20 @@ public ListIterator<E> listIterator(int index) {
     public List<E> subList(int fromIndex, int toIndex) {
         throw new UnsupportedOperationException("This operation is not supported");
     }
+
+	// this is added in JDK 21, so not @Override here
+	@SuppressWarnings("UnusedReturnValue")
+	public List<E> reversed() {
+		throw new UnsupportedOperationException("This operation is not supported");
+	}
+
+	// this is added in JDK 21, so not @Override here
+	public E getFirst() {
+		throw new UnsupportedOperationException("This operation is not supported");
+	}
+
+	// this is added in JDK 21, so not @Override here
+	public E getLast() {
+		throw new UnsupportedOperationException("This operation is not supported");
+	}
 }
diff --git a/src/test/java/org/dstadler/commons/collections/ObjectAccessorListTest.java b/src/test/java/org/dstadler/commons/collections/ObjectAccessorListTest.java
@@ -9,8 +9,10 @@
 import org.junit.jupiter.api.Test;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.concurrent.atomic.AtomicLong;
 
 public class ObjectAccessorListTest  extends AbstractUnsupportedCollectionTest<ObjectAccessorList<Integer, Object>> {
@@ -22,6 +24,8 @@ public static void setUpClass() {
         IGNORED_METHODS.add("isEmpty");
         IGNORED_METHODS.add("iterator");
         IGNORED_METHODS.add("forEach");
+        IGNORED_METHODS.add("getFirst");
+        IGNORED_METHODS.add("getLast");
     }
 
     @Override
@@ -48,6 +52,14 @@ public void testObjectAccess() {
         assertEquals(3, list.size());
         assertFalse(list.isEmpty());
 
+		assertThrows(IndexOutOfBoundsException.class,
+				() -> list.get(2363));
+
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertEquals((Integer)obj1.hashCode(), ((UnsupportedList<Integer>)list).getFirst());
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertEquals((Integer)obj3.hashCode(), ((UnsupportedList<Integer>)list).getLast());
+
         Iterator<Integer> it = list.iterator();
         assertTrue(it.hasNext());
         assertEquals((Integer)obj1.hashCode(), it.next());
@@ -85,7 +97,15 @@ public void testObjectAccessWithChanges() {
         assertEquals(2, list.size());
         assertFalse(list.isEmpty());
 
-        Iterator<Integer> it = list.iterator();
+		assertThrows(IndexOutOfBoundsException.class,
+				() -> list.get(2363));
+
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertEquals((Integer)obj1.hashCode(), ((UnsupportedList<Integer>)list).getFirst());
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertEquals((Integer)obj3.hashCode(), ((UnsupportedList<Integer>)list).getLast());
+
+		Iterator<Integer> it = list.iterator();
         assertTrue(it.hasNext());
         assertEquals((Integer)obj1.hashCode(), it.next());
         assertTrue(it.hasNext());
@@ -113,4 +133,22 @@ public void testObjectAccessWithChanges() {
 
         assertTrue(list.isEmpty());
     }
+
+	@Test
+	public void testEmpty() {
+		List<Integer> list = new ObjectAccessorList<>(Collections.emptyList(), Object::hashCode) {};
+		assertTrue(list.isEmpty());
+		//noinspection ConstantValue
+		assertEquals(0, list.size());
+		assertThrows(IndexOutOfBoundsException.class,
+				() -> list.get(0));
+		assertThrows(IndexOutOfBoundsException.class,
+				() -> list.get(2363));
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertThrows(NoSuchElementException.class,
+				() -> ((UnsupportedList<Integer>)list).getFirst());
+		//noinspection CastCanBeRemovedNarrowingVariableType
+		assertThrows(NoSuchElementException.class,
+				() -> ((UnsupportedList<Integer>)list).getLast());
+	}
 }
diff --git a/src/test/java/org/dstadler/commons/collections/UnsupportedListTest.java b/src/test/java/org/dstadler/commons/collections/UnsupportedListTest.java
@@ -26,5 +26,11 @@ public void test() {
 				() -> coll.add(null));
 		assertThrows(UnsupportedOperationException.class,
 				() -> coll.get(0));
+		assertThrows(UnsupportedOperationException.class,
+				coll::reversed);
+		assertThrows(UnsupportedOperationException.class,
+				coll::getFirst);
+		assertThrows(UnsupportedOperationException.class,
+				coll::getLast);
 	}
 }