jdk/test/java/util/Vector/ArrayManagement.java
changeset 35383 61820dd2360e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/Vector/ArrayManagement.java	Mon Jan 25 16:07:00 2016 -0800
@@ -0,0 +1,218 @@
+/*
+ * Copyright 2016 Google, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8148174
+ * @summary brittle white box test of internal array management
+ * @run testng ArrayManagement
+ */
+
+import java.lang.reflect.Field;
+import java.util.AbstractList;
+import java.util.Vector;
+import java.util.Collections;
+import java.util.List;
+import java.util.SplittableRandom;
+
+import org.testng.annotations.Test;
+import static org.testng.Assert.*;
+
+public class ArrayManagement {
+
+    /**
+     * A Vector that exposes all protected elements, and checks class
+     * invariants.
+     */
+    static class PublicVector<E> extends Vector<E> {
+        public PublicVector() { super(); }
+        public PublicVector(int capacity) { super(capacity); }
+        public PublicVector(int capacity, int capacityIncrement) {
+            super(capacity, capacityIncrement);
+        }
+        public Object[] elementData()  { return elementData; }
+        public int modCount()          { return modCount; }
+        public int capacityIncrement() { return capacityIncrement; }
+        public int capacity()          { return elementData.length; }
+
+        public void ensureCapacity(int minCapacity) {
+            int oldCapacity = capacity();
+            int oldModCount = modCount();
+            super.ensureCapacity(minCapacity);
+            assertTrue(capacity() >= minCapacity);
+            if (minCapacity <= oldCapacity)
+                assertEquals(capacity(), oldCapacity);
+            if (minCapacity > 0)
+                assertEquals(modCount(), oldModCount + 1);
+        }
+    }
+
+    static final int DEFAULT_CAPACITY = 10;
+    static final SplittableRandom rnd = new SplittableRandom();
+
+    static int newCapacity(int oldCapacity) {
+        return 2 * oldCapacity;
+    }
+
+    static List<Object> singletonList() {
+        return Collections.singletonList(Boolean.TRUE);
+    }
+
+    /** Opportunistically randomly test various add operations. */
+    static void addOneElement(PublicVector<Object> list) {
+        int size = list.size();
+        int modCount = list.modCount();
+        switch (rnd.nextInt(4)) {
+        case 0: assertTrue(list.add(Boolean.TRUE)); break;
+        case 1: list.add(size, Boolean.TRUE); break;
+        case 2: assertTrue(list.addAll(singletonList())); break;
+        case 3: assertTrue(list.addAll(size, singletonList())); break;
+        default: throw new AssertionError();
+        }
+        assertEquals(list.modCount(), modCount + 1);
+        assertEquals(list.size(), size + 1);
+    }
+
+    @Test public void defaultCapacity() {
+        PublicVector<Object> list = new PublicVector<>();
+        assertEquals(new PublicVector<Object>().capacity(), DEFAULT_CAPACITY);
+        for (int i = 0; i < DEFAULT_CAPACITY; i++) {
+            addOneElement(list);
+            assertEquals(list.capacity(), DEFAULT_CAPACITY);
+        }
+        addOneElement(list);
+        assertEquals(list.capacity(), newCapacity(DEFAULT_CAPACITY));
+    }
+
+    @Test public void defaultCapacityEnsureCapacity() {
+        PublicVector<Object> list = new PublicVector<>();
+        for (int i = 0; i <= DEFAULT_CAPACITY; i++) {
+            list.ensureCapacity(i);     // no-op!
+            assertEquals(list.capacity(), DEFAULT_CAPACITY);
+        }
+        for (int i = 0; i < DEFAULT_CAPACITY; i++) {
+            addOneElement(list);
+            assertEquals(list.capacity(), DEFAULT_CAPACITY);
+        }
+        addOneElement(list);
+        assertEquals(list.capacity(), newCapacity(DEFAULT_CAPACITY));
+        {
+            int capacity = list.capacity();
+            list.ensureCapacity(capacity + 1);
+            assertEquals(list.capacity(), newCapacity(capacity));
+        }
+        {
+            int capacity = list.capacity();
+            list.ensureCapacity(3 * capacity);
+            assertEquals(list.capacity(), 3 * capacity);
+        }
+    }
+
+    @Test public void ensureCapacityBeyondDefaultCapacity() {
+        PublicVector<Object> list = new PublicVector<>();
+        list.ensureCapacity(DEFAULT_CAPACITY + 1);
+        assertEquals(list.capacity(), newCapacity(DEFAULT_CAPACITY));
+    }
+
+    @Test public void explicitZeroCapacity() {
+        PublicVector<Object> list = new PublicVector<>(0);
+        assertEquals(list.capacity(), 0);
+        addOneElement(list);
+        assertEquals(list.capacity(), 1);
+        addOneElement(list);
+        assertEquals(list.capacity(), 2);
+        addOneElement(list);
+        assertEquals(list.capacity(), 4);
+        addOneElement(list);
+        assertEquals(list.capacity(), 4);
+        addOneElement(list);
+        assertEquals(list.capacity(), 8);
+        addOneElement(list);
+        assertEquals(list.capacity(), 8);
+        addOneElement(list);
+        assertEquals(list.capacity(), 8);
+        list.clear();
+        assertEquals(list.capacity(), 8);
+    }
+
+    @Test public void explicitZeroCapacityWithCapacityIncrement() {
+        PublicVector<Object> list = new PublicVector<>(0, 2);
+        assertEquals(list.capacity(), 0);
+        addOneElement(list);
+        assertEquals(list.capacity(), 2);
+        addOneElement(list);
+        assertEquals(list.capacity(), 2);
+        addOneElement(list);
+        assertEquals(list.capacity(), 4);
+        addOneElement(list);
+        assertEquals(list.capacity(), 4);
+        addOneElement(list);
+        assertEquals(list.capacity(), 6);
+        addOneElement(list);
+        assertEquals(list.capacity(), 6);
+        addOneElement(list);
+        assertEquals(list.capacity(), 8);
+        list.clear();
+        assertEquals(list.capacity(), 8);
+    }
+
+    @Test public void explicitLargeCapacity() {
+        int n = DEFAULT_CAPACITY * 3;
+        PublicVector<Object> list = new PublicVector<>(n);
+        assertEquals(list.capacity(), n);
+        list.ensureCapacity(0);
+        list.ensureCapacity(n);
+        for (int i = 0; i < n; i++) addOneElement(list);
+        assertEquals(list.capacity(), n);
+
+        addOneElement(list);
+        assertEquals(list.capacity(), newCapacity(n));
+    }
+
+    @Test public void explicitLargeCapacityWithCapacityIncrement() {
+        int n = DEFAULT_CAPACITY * 3;
+        PublicVector<Object> list = new PublicVector<>(n, 2);
+        assertEquals(list.capacity(), n);
+        list.ensureCapacity(0);
+        list.ensureCapacity(n);
+        for (int i = 0; i < n; i++) addOneElement(list);
+        assertEquals(list.capacity(), n);
+
+        addOneElement(list);
+        assertEquals(list.capacity(), n + 2);
+    }
+
+    @Test public void emptyArraysAreNotShared() {
+        assertNotSame(new PublicVector<Object>(0).elementData(),
+                      new PublicVector<Object>(0).elementData());
+    }
+
+    @Test public void negativeCapacity() {
+        for (int capacity : new int[] { -1, Integer.MIN_VALUE }) {
+            try {
+                new Vector<Object>(capacity);
+                fail("should throw");
+            } catch (IllegalArgumentException success) {}
+        }
+    }
+}