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/*
* Copyright (c) 2006, 2012, 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.
*/
/* @test
* @bug 6364692
* @summary When the "java.rmi.server.randomIDs" system property is
* not defined, the ObjID() constructor should behave as if it were
* set to "true" and generate random object numbers; if the property
* is defined to something other than "true" (ignoring case), then
* ObjID() should still generate sequential object numbers.
* @author Peter Jones
*
* @run main/othervm RandomIDs random
* @run main/othervm -Djava.rmi.server.randomIDs=true RandomIDs random
* @run main/othervm -Djava.rmi.server.randomIDs=false RandomIDs sequential
*/
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.rmi.server.ObjID;
public class RandomIDs {
private static final int COUNT = 10000;
public static void main(String[] args) throws Exception {
boolean shouldBeRandom = false;
boolean shouldBeSequential = false;
String usage = "Usage: java RandomIDs [random|sequential]";
if (args.length != 1) {
System.err.println(usage);
throw new Error("wrong number of arguments");
} else if (args[0].equals("random")) {
shouldBeRandom = true;
} else if (args[0].equals("sequential")) {
shouldBeSequential = true;
} else {
System.err.println(usage);
throw new Error("invalid argument");
}
System.err.println("\nRegression test for bug 6364692\n");
String propertyValue = System.getProperty("java.rmi.server.randomIDs");
System.err.println(
"Value of java.rmi.server.randomIDs system property: " +
(propertyValue != null ? "\"" + propertyValue + "\"" : null));
System.err.println(
"Expecting object numbers of unique ObjIDs to be: " + args[0]);
/*
* Get the 64-bit "object number" component of COUNT number of
* unique (not "well-known") ObjID instances created in
* sequence, by writing each to a dummy ObjectOutputStream and
* trapping the first writeLong invocation on the stream.
*/
final long[] objnums = new long[COUNT];
for (int i = 0; i < COUNT; i++) {
final int j = i;
class Escape extends RuntimeException { }
try {
new ObjID().write(new ObjectOutputStream(new OutputStream() {
public void write(int b) { }
}) {
public void writeLong(long val) throws IOException {
objnums[j] = val;
throw new Escape();
}
});
throw new Error("writeLong not invoked");
} catch (Escape e) {
}
}
/*
* If the object numbers should be random, then verify that
* they are. (This verification is certainly not a thorough
* evaluation of randomness, but it performs a couple of
* simple checks to catch mistakes in ObjID's application of a
* CSPRNG: are roughly half the bits set, and can the sequence
* be used to get a rough Monte Carlo estimate of pi. Errors
* up to 5% are tolerated for both checks.)
*/
if (shouldBeRandom) {
int bitCount = 0;
int piHitCount = 0;
for (int i = 0; i < COUNT; i++) {
bitCount += Long.bitCount(objnums[i]);
double x = ((double) (objnums[i] >>> 32)) / (1L << 32);
double y = ((double) (objnums[i] & 0xFFFFFFFFL)) / (1L << 32);
if (((x * x) + (y * y)) <= 1.0) {
piHitCount++;
}
}
int bitCountTarget = COUNT * 32;
double bitCountError =
((double) (bitCount - bitCountTarget)) / bitCountTarget;
if (Math.abs(bitCountError) > 0.05) { // tolerate 5% error
throw new Error("TEST FAILED: " +
"bitCount == " + bitCount);
}
double piEstimate = ((double) piHitCount / COUNT) * 4.0;
double piEstimateError = (piEstimate - Math.PI) / Math.PI;
if (Math.abs(piEstimateError) > 0.05) { // tolerate 5% error
throw new Error("TEST FAILED: " +
"piEstimate == " + piEstimate);
}
}
/*
* If the object numbers should be sequential, then verify
* that they are.
*/
if (shouldBeSequential) {
long first = objnums[0];
/*
* This test currently verifies that the first object
* number is zero, but that could be false if one or more
* remote objects get exported as part of VM startup-- if
* that starts happening, this check could be relaxed.
*/
if (first != 0) {
throw new Error("TEST FAILED: " +
"first object number == " + first +
" (not zero)");
}
for (int i = 1; i < COUNT; i++) {
if (objnums[i] != first + i) {
throw new Error("TEST FAILED: first == " + first + ", " +
"objnums[" + i + "] == " + objnums[i]);
}
}
}
System.err.println("TEST PASSED");
}
}
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