Java version Util
/** *Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] *Licensed 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 */ /** *Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] *Licensed 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 com.google.code.yanf4j.util; import java.io.IOException; import java.lang.reflect.Method; import java.net.InetAddress; import java.net.InetSocketAddress; import java.nio.channels.Selector; import java.nio.channels.spi.SelectorProvider; /** * System utils * * @author dennis * */ public final class SystemUtils { private SystemUtils() { } public static final String OS_NAME = System.getProperty("os.name"); private static boolean isLinuxPlatform = false; static { if (OS_NAME != null && OS_NAME.toLowerCase().indexOf("linux") >= 0) { isLinuxPlatform = true; } } public static final String JAVA_VERSION = System .getProperty("java.version"); private static boolean isAfterJava6u4Version = false; static { if (JAVA_VERSION != null) { // java4 or java5 if (JAVA_VERSION.indexOf("1.4.") >= 0 || JAVA_VERSION.indexOf("1.5.") >= 0) { isAfterJava6u4Version = false; } else if (JAVA_VERSION.indexOf("1.6.") >= 0) { int index = JAVA_VERSION.indexOf("_"); if (index > 0) { String subVersionStr = JAVA_VERSION.substring(index + 1); if (subVersionStr != null && subVersionStr.length() > 0) { try { int subVersion = Integer.parseInt(subVersionStr); if (subVersion >= 4) { isAfterJava6u4Version = true; } } catch (NumberFormatException e) { } } } // after java6 } else { isAfterJava6u4Version = true; } } } public static final boolean isLinuxPlatform() { return isLinuxPlatform; } public static final boolean isAfterJava6u4Version() { return isAfterJava6u4Version; } public static void main(String[] args) { System.out.println(isAfterJava6u4Version()); } public static final int getSystemThreadCount() { return getCpuProcessorCount(); } public static final int getCpuProcessorCount() { return Runtime.getRuntime().availableProcessors(); } public static final Selector openSelector() throws IOException { Selector result = null; // check if it is linux os if (SystemUtils.isLinuxPlatform()) { try { Class<?> providerClazz = Class .forName("sun.nio.ch.EPollSelectorProvider"); if (providerClazz != null) { try { Method method = providerClazz.getMethod("provider"); if (method != null) { SelectorProvider selectorProvider = (SelectorProvider) method .invoke(null); if (selectorProvider != null) { result = selectorProvider.openSelector(); } } } catch (Exception e) { // ignore } } } catch (Exception e) { // ignore } } if (result == null) { result = Selector.open(); } return result; } public static final String getRawAddress(InetSocketAddress inetSocketAddress) { InetAddress address = inetSocketAddress.getAddress(); return address != null ? address.getHostAddress() : inetSocketAddress .getHostName(); } }