--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/lib/testlibrary/jdk/testlibrary/OptimalCapacity.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. 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.
+ */
+
+package jdk.testlibrary;
+
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+
+/**
+ * Utility functions to check that the static storages are pre-sized
+ * optimally.
+ */
+public final class OptimalCapacity {
+
+ private OptimalCapacity() {}
+
+ /**
+ * Checks adequacy of the initial capacity of a static field
+ * of type {@code ArrayList}.
+ *
+ * Having
+ * <pre>
+ * class XClass {
+ * static ArrayList theList = new ArrayList(N);
+ * }
+ * </pre>
+ *
+ * you should call from the test
+ *
+ * <pre>
+ * OptimalCapacity.assertProperlySized(XClass.class, "theList", N);
+ * </pre>
+ */
+ public static void ofArrayList(Class<?> clazz, String fieldName,
+ int initialCapacity)
+ {
+ try {
+ Field field = clazz.getDeclaredField(fieldName);
+ field.setAccessible(true);
+ Object obj = field.get(null);
+ if (!ArrayList.class.equals(obj.getClass())) {
+ throw new RuntimeException("'" + field +
+ "' expected to be of type ArrayList");
+ }
+ ArrayList<?> list = (ArrayList<?>)obj;
+
+ // For ArrayList the optimal capacity is its final size
+ if (list.size() != initialCapacity) {
+ throw new RuntimeException("Size of '" + field +
+ "' is " + list.size() +
+ ", but expected to be " + initialCapacity);
+ }
+ if (internalArraySize(list) != initialCapacity) {
+ throw new RuntimeException("Capacity of '" + field +
+ "' is " + internalArraySize(list) +
+ ", but expected to be " + initialCapacity);
+ }
+ } catch (ReflectiveOperationException roe) {
+ throw new RuntimeException(roe);
+ }
+ }
+
+ /**
+ * Checks adequacy of the initial capacity of a static field
+ * of type {@code HashMap}.
+ *
+ * Having
+ * <pre>
+ * class XClass {
+ * static HashMap theMap = new HashMap(N);
+ * }
+ * </pre>
+ *
+ * you should call from the test
+ *
+ * <pre>
+ * OptimalCapacity.ofHashMap(XClass.class, "theMap", N);
+ * </pre>
+ */
+ public static void ofHashMap(Class<?> clazz, String fieldName,
+ int initialCapacity)
+ {
+ try {
+ Field field = clazz.getDeclaredField(fieldName);
+ field.setAccessible(true);
+ Object obj = field.get(null);
+ if (!HashMap.class.equals(obj.getClass())) {
+ throw new RuntimeException(field +
+ " expected to be of type HashMap");
+ }
+ HashMap<?,?> map = (HashMap<?,?>)obj;
+
+ // Check that the map allocates only necessary amount of space
+ HashMap<Object, Object> tmp = new HashMap<>(map);
+ if (internalArraySize(map) != internalArraySize(tmp)) {
+ throw new RuntimeException("Final capacity of '" + field +
+ "' is " + internalArraySize(map) +
+ ", which exceeds necessary minimum " + internalArraySize(tmp));
+ }
+
+ // Check that map is initially properly sized
+ tmp = new HashMap<>(initialCapacity);
+ tmp.put(new Object(), new Object()); // trigger storage init
+ if (internalArraySize(map) != internalArraySize(tmp)) {
+ throw new RuntimeException("Requested capacity of '" + field +
+ "' was " + initialCapacity +
+ ", which resulted in final capacity " + internalArraySize(tmp) +
+ ", which differs from necessary minimum " + internalArraySize(map));
+ }
+
+ } catch (ReflectiveOperationException roe) {
+ throw new RuntimeException(roe);
+ }
+ }
+
+ /**
+ * Checks adequacy of the expected maximum size of a static field
+ * of type {@code IdentityHashMap}.
+ *
+ * Having
+ * <pre>
+ * class XClass {
+ * static IdentityHashMap theMap = new IdentityHashMap(M);
+ * }
+ * </pre>
+ *
+ * you should call from the test
+ *
+ * <pre>
+ * OptimalCapacity.ofIdentityHashMap(XClass.class, "theMap", M);
+ * </pre>
+ */
+ public static void ofIdentityHashMap(Class<?> clazz, String fieldName,
+ int expectedMaxSize)
+ {
+ try {
+ Field field = clazz.getDeclaredField(fieldName);
+ field.setAccessible(true);
+ Object obj = field.get(null);
+ if (!IdentityHashMap.class.equals(obj.getClass())) {
+ throw new RuntimeException("'" + field +
+ "' expected to be of type IdentityHashMap");
+ }
+ IdentityHashMap<?,?> map = (IdentityHashMap<?,?>)obj;
+
+ // Check that size of map is what was expected
+ if (map.size() != expectedMaxSize) {
+ throw new RuntimeException("Size of '" + field +
+ "' is " + map.size() +
+ ", which differs from expected " + expectedMaxSize);
+ }
+
+ // Check that the map allocated only necessary amount of memory
+ IdentityHashMap<Object, Object> tmp = new IdentityHashMap<>(map);
+ if (internalArraySize(map) != internalArraySize(tmp)) {
+ throw new RuntimeException("Final capacity of '" + field +
+ "' is " + internalArraySize(map) +
+ ", which exceeds necessary minimum " + internalArraySize(tmp));
+ }
+
+ // Check that map was initially properly sized
+ tmp = new IdentityHashMap<>(expectedMaxSize);
+ tmp.put(new Object(), new Object()); // trigger storage init
+ if (internalArraySize(map) != internalArraySize(tmp)) {
+ throw new RuntimeException("Requested number of elements in '" + field +
+ "' was " + expectedMaxSize +
+ ", which resulted in final capacity " + internalArraySize(tmp) +
+ ", which differs from necessary minimum " + internalArraySize(map));
+ }
+ } catch (ReflectiveOperationException roe) {
+ throw new RuntimeException(roe);
+ }
+ }
+
+ /**
+ * Returns size of the internal storage.
+ */
+ private static int internalArraySize(Object container)
+ throws ReflectiveOperationException {
+ Field field;
+ if (ArrayList.class.equals(container.getClass())) {
+ field = ArrayList.class.getDeclaredField("elementData");
+ } else if (HashMap.class.equals(container.getClass())) {
+ field = HashMap.class.getDeclaredField("table");
+ } else if (IdentityHashMap.class.equals(container.getClass())) {
+ field = IdentityHashMap.class.getDeclaredField("table");
+ } else {
+ throw new RuntimeException("Unexpected class " +
+ container.getClass());
+ }
+ field.setAccessible(true);
+ return ((Object[])field.get(container)).length;
+ }
+}