gemfire-core/src/main/java/com/gemstone/gemfire/internal/lang/SystemUtils.java

/*
 * =========================================================================
 *  Copyright (c) 2002-2014 Pivotal Software, Inc. All Rights Reserved.
 *  This product is protected by U.S. and international copyright
 *  and intellectual property laws. Pivotal products are covered by
 *  more patents listed at http://www.pivotal.io/patents.
 * =========================================================================
 */

package com.gemstone.gemfire.internal.lang;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.StringTokenizer;

/**
 * The SystemUtils class is an abstract utility class for working with, invoking methods and accessing properties
 * of the Java System class.
 * 
 * @author John Blum
 * @see java.lang.System
 * @since 6.8
 */
@SuppressWarnings("unused")
public class SystemUtils {

  public static final String CURRENT_DIRECTORY = System.getProperty("user.dir");

  // Java Virtual Machine (JVM) Names
  public static final String IBM_J9_JVM_NAME = "J9";
  public static final String JAVA_HOTSPOT_JVM_NAME = "HotSpot";
  public static final String ORACLE_JROCKIT_JVM_NAME = "JRockit";

  // Java Virtual Machine (JVM) Vendor Names
  public static final String APPLE_JVM_VENDOR_NAME = "Apple";
  public static final String IBM_JVM_NAME = "IBM";
  public static final String ORACLE_JVM_VENDOR_NAME = "Oracle";

  // Operating System Names
  public static final String LINUX_OS_NAME = "Linux";
  public static final String MAC_OSX_NAME = "Mac";
  public static final String WINDOWS_OS_NAME = "Windows";

  /**
   * Utility method to determine whether the installed Java Runtime Environment (JRE) is minimally at the specified,
   * expected version.  Typically, Java versions are of the form "1.6.0_31"...
   * 
   * @param expectedVersion an int value specifying the minimum expected version of the Java Runtime.
   * @return a boolean value indicating if the Java Runtime meets the expected version requirement.
   * @see java.lang.System#getProperty(String) with "java.version".
   */
  public static boolean isJavaVersionAtLeast(final String expectedVersion) {
    String actualVersionDigits = StringUtils.getDigitsOnly(System.getProperty("java.version"));

    String expectedVersionDigits = StringUtils.padEnding(StringUtils.getDigitsOnly(expectedVersion), '0',
      actualVersionDigits.length());

    try {
      return (Long.parseLong(actualVersionDigits) >= Long.parseLong(expectedVersionDigits));
    }
    catch (NumberFormatException ignore) {
      return false;
    }
  }

  /**
   * Utility method to determine whether the Java application process is executing on the Apple JVM.
   * 
   * @return a boolean value indicating whether the Java application process is executing and running 
   * on the Apple JVM.
   * @see #isJvmVendor(String)
   */
  public static boolean isAppleJVM() {
    return isJvmVendor(APPLE_JVM_VENDOR_NAME);
  }

  /**
   * Utility method to determine whether the Java application process is executing on the Oracle JVM.
   *
   * @return a boolean value indicating whether the Java application process is executing and running 
   * on the Oracle JVM.
   * @see #isJvmVendor(String)
   */
  public static boolean isOracleJVM() {
    return isJvmVendor(ORACLE_JVM_VENDOR_NAME);
  }

  // @see java.lang.System#getProperty(String) with 'java.vm.vendor'.
  private static boolean isJvmVendor(final String expectedJvmVendorName) {
    String jvmVendor = System.getProperty("java.vm.vendor");
    return (jvmVendor != null && jvmVendor.contains(expectedJvmVendorName));
  }

  /**
   * Utility method to determine whether the Java application process is executing on the Java HotSpot VM.
   * Client or Server VM does not matter.
   * 
   * @return a boolean value indicating whether the Java application process is executing on the Java HotSpot VM.
   * @see #isJVM(String)
   */
  public static boolean isHotSpotVM() {
    return isJVM(JAVA_HOTSPOT_JVM_NAME);
  }

  /**
   * Utility method to determine whether the Java application process is executing on the IBM J9 VM.
   * 
   * @return a boolean value indicating whether the Java application process is executing on the IBM J9 VM.
   * @see #isJVM(String)
   */
  public static boolean isJ9VM() {
    return isJVM(IBM_J9_JVM_NAME);
  }

  /**
   * Utility method to determine whether the Java application process is executing on the Oracle JRockit VM.
   * Client or Server VM does not matter.
   * 
   * @return a boolean value indicating whether the Java application process is executing on the Oracle JRockit VM.
   * @see #isJVM(String)
   */
  public static boolean isJRockitVM() {
    return isJVM(ORACLE_JROCKIT_JVM_NAME);
  }

  // @see java.lang.System#getProperty(String) with "java.vm.name".
  private static boolean isJVM(final String expectedJvmName) {
    String jvmName = System.getProperty("java.vm.name");
    return (jvmName != null && jvmName.contains(expectedJvmName));
  }

  /**
   * Utility method that determines whether the Java application process is executing in a Linux
   * operating system environment.
   * 
   * @return a boolean value indicating whether the Java application process is executing in Linux.
   * @see #isOS(String)
   */
  public static boolean isLinux() {
    return isOS(LINUX_OS_NAME);
  }

  /**
   * Utility method that determines whether the Java application process is executing in a Apple Mac OSX
   * operating system environment.
   * 
   * @return a boolean value indicating whether the Java application process is executing in Mac OSX.
   * @see #isOS(String)
   */
  public static boolean isMacOSX() {
    return isOS(MAC_OSX_NAME);
  }

  /**
   * Utility method that determines whether the Java application process is executing in a Microsoft Windows-based
   * operating system environment.
   * 
   * @return a boolean value indicating whether the Java application process is executing in Windows.
   * @see #isOS(String)
   */
  public static boolean isWindows() {
    return isOS(WINDOWS_OS_NAME);
  }


  /**
   * Returns true if the specified location is in the JVM classpath. This may
   * ignore additions to the classpath that are not reflected by the value in
   * <code>System.getProperty("java.class.path")</code>.
   * 
   * @param location the directory or jar name to test for
   * @return true if location is in the JVM classpath
   * @throws MalformedURLException
   */
  public static boolean isInClassPath(String location) throws MalformedURLException {
    return isInClassPath(new File(location).toURI().toURL());
  }
  
  /**
   * Returns true if the specified location is in the JVM classpath. This may
   * ignore additions to the classpath that are not reflected by the value in
   * <code>System.getProperty("java.class.path")</code>.
   * 
   * @param location the directory or jar URL to test for
   * @return true if location is in the JVM classpath
   * @throws MalformedURLException
   */
  public static boolean isInClassPath(URL location) throws MalformedURLException {
    String classPath = System.getProperty("java.class.path");
    StringTokenizer st = new StringTokenizer(classPath, File.pathSeparator);
    while (st.hasMoreTokens()) {
      String path =st.nextToken();
      if (location.equals(new File(path).toURI().toURL())) {
        return true;
      }
    }
    return false;
  }
  
  // @see java.lang.System#getProperty(String) with "os.name".
  private static boolean isOS(final String expectedOsName) {
    String osName = System.getProperty("os.name");
    return (osName != null && osName.contains(expectedOsName));
  }

}