SystemUtils.java Source code

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/**
 *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();
    }
}