org.jboss.netty.util.internal.DetectionUtil Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.jboss.netty.util.internal;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Queue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Utility that detects various properties specific to the current runtime
* environment, such as Java version and the availability of the
* {@code sun.misc.Unsafe} object.
*
*
* You can disable the use of {@code sun.misc.Unsafe} if you specify
* the System property org.jboss.netty.tryUnsafe with
* value of {@code false}. Default is {@code true}.
*/
public final class DetectionUtil {
private static final int JAVA_VERSION = javaVersion0();
private static final boolean HAS_UNSAFE = hasUnsafe(AtomicInteger.class.getClassLoader());
private static final boolean IS_WINDOWS;
static {
String os = SystemPropertyUtil.get("os.name", "").toLowerCase();
// windows
IS_WINDOWS = os.contains("win");
}
/**
* Return {@code true} if the JVM is running on Windows
*
*/
public static boolean isWindows() {
return IS_WINDOWS;
}
public static boolean hasUnsafe() {
return HAS_UNSAFE;
}
public static int javaVersion() {
return JAVA_VERSION;
}
private static boolean hasUnsafe(ClassLoader loader) {
boolean noUnsafe = SystemPropertyUtil.getBoolean("io.netty.noUnsafe", false);
if (noUnsafe) {
return false;
}
// Legacy properties
boolean tryUnsafe;
if (SystemPropertyUtil.contains("io.netty.tryUnsafe")) {
tryUnsafe = SystemPropertyUtil.getBoolean("io.netty.tryUnsafe", true);
} else {
tryUnsafe = SystemPropertyUtil.getBoolean("org.jboss.netty.tryUnsafe", true);
}
if (!tryUnsafe) {
return false;
}
try {
Class> unsafeClazz = Class.forName("sun.misc.Unsafe", true, loader);
return hasUnsafeField(unsafeClazz);
} catch (Exception e) {
// Ignore
}
return false;
}
private static boolean hasUnsafeField(final Class> unsafeClass) throws PrivilegedActionException {
return AccessController.doPrivileged(new PrivilegedExceptionAction() {
public Boolean run() throws Exception {
unsafeClass.getDeclaredField("theUnsafe");
return true;
}
});
}
private static int javaVersion0() {
try {
// Check if its android, if so handle it the same way as java6.
//
// See https://github.com/netty/netty/issues/282
Class.forName("android.app.Application");
return 6;
} catch (ClassNotFoundException e) {
//Ignore
}
try {
Class.forName(
"java.util.concurrent.LinkedTransferQueue", false,
BlockingQueue.class.getClassLoader());
return 7;
} catch (Exception e) {
// Ignore
}
try {
Class.forName(
"java.util.ArrayDeque", false, Queue.class.getClassLoader());
return 6;
} catch (Exception e) {
// Ignore
}
return 5;
}
private DetectionUtil() {
// only static method supported
}
}