All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.jboss.netty.util.internal.DetectionUtil Maven / Gradle / Ivy

There is a newer version: 0.10.0
Show newest version
/*
 * 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 } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy