Java version Util : JVM Tool Interface « Development Class « Java

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Java » Development Class » JVM Tool Interface 




Java version Util
        

/**
 *Copyright [2009-2010] [dennis zhuang([email protected])]
 *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([email protected])]
 *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 = (SelectorProvidermethod
                  .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();
  }
}

   
    
    
    
    
    
    
    
  














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