8189319: Add a java.util.Properties constructor that takes an initial capacity
Reviewed-by: martin, mchung, rriggs
--- a/src/java.base/share/classes/java/lang/System.java Mon Oct 30 07:06:49 2017 -0700
+++ b/src/java.base/share/classes/java/lang/System.java Mon Oct 30 16:16:01 2017 -0700
@@ -1937,7 +1937,7 @@
// initialization. So make sure the "props" is available at the
// very beginning of the initialization and all system properties to
// be put into it directly.
- props = new Properties();
+ props = new Properties(84);
initProperties(props); // initialized by the VM
// There are certain system configurations that may be controlled by
--- a/src/java.base/share/classes/java/util/Properties.java Mon Oct 30 07:06:49 2017 -0700
+++ b/src/java.base/share/classes/java/util/Properties.java Mon Oct 30 16:16:01 2017 -0700
@@ -122,6 +122,10 @@
* <p>This class is thread-safe: multiple threads can share a single
* {@code Properties} object without the need for external synchronization.
*
+ * @apiNote
+ * The {@code Properties} class does not inherit the concept of a load factor
+ * from its superclass, {@code Hashtable}.
+ *
* @author Arthur van Hoff
* @author Michael McCloskey
* @author Xueming Shen
@@ -148,25 +152,49 @@
* simple read operations. Writes and bulk operations remain synchronized,
* as in Hashtable.
*/
- private transient ConcurrentHashMap<Object, Object> map =
- new ConcurrentHashMap<>(8);
+ private transient ConcurrentHashMap<Object, Object> map;
/**
* Creates an empty property list with no default values.
+ *
+ * @implNote The initial capacity of a {@code Properties} object created
+ * with this constructor is unspecified.
*/
public Properties() {
- this(null);
+ this(null, 8);
+ }
+
+ /**
+ * Creates an empty property list with no default values, and with an
+ * initial size accommodating the specified number of elements without the
+ * need to dynamically resize.
+ *
+ * @param initialCapacity the {@code Properties} will be sized to
+ * accommodate this many elements
+ * @throws IllegalArgumentException if the initial capacity is less than
+ * zero.
+ */
+ public Properties(int initialCapacity) {
+ this(null, initialCapacity);
}
/**
* Creates an empty property list with the specified defaults.
*
+ * @implNote The initial capacity of a {@code Properties} object created
+ * with this constructor is unspecified.
+ *
* @param defaults the defaults.
*/
public Properties(Properties defaults) {
+ this(defaults, 8);
+ }
+
+ private Properties(Properties defaults, int initialCapacity) {
// use package-private constructor to
// initialize unused fields with dummy values
super((Void) null);
+ map = new ConcurrentHashMap<>(initialCapacity);
this.defaults = defaults;
}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/util/Properties/InitialCapacity.java Mon Oct 30 16:16:01 2017 -0700
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+
+import java.util.Properties;
+import org.testng.annotations.Test;
+
+/*
+ * @test
+ * @bug 8189319
+ * @summary Test that Properties(int initialCapacity) throws exceptions (or
+ doesn't) as expected
+ * @run testng InitialCapacity
+ */
+public class InitialCapacity {
+ @Test(expectedExceptions = IllegalArgumentException.class)
+ public void negativeInitCap() { Properties p = new Properties(-1); }
+
+ @Test
+ public void positiveInitCap() { Properties p = new Properties(10); }
+}