/logback-core/src/main/java/ch/qos/logback/core/util/EnvUtil.java

/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.util;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Ceki Gücü
 */
public class EnvUtil {


  static private boolean isJDK_N_OrHigher(int n) {
     List<String> versionList = new ArrayList<String>();
     // this code should work at least until JDK 10 (assuming n parameter is
     // always 6 or more)
     for (int i = 0; i < 5; i++) {
       versionList.add("1." + (n + i));
     }

     String javaVersion = System.getProperty("java.version");
     if (javaVersion == null) {
       return false;
     }
     for (String v : versionList) {
       if (javaVersion.startsWith(v))
         return true;
     }
     return false;
   }

  static public boolean isJDK5() {
    return isJDK_N_OrHigher(5);
  }

   static public boolean isJDK6OrHigher() {
     return isJDK_N_OrHigher(6);
   }

   static public boolean isJDK7OrHigher() {
     return isJDK_N_OrHigher(7);
   }

  static public boolean isJaninoAvailable() {
    ClassLoader classLoader = EnvUtil.class.getClassLoader();
    try {
      Class<?> bindingClass = classLoader.loadClass("org.codehaus.janino.ScriptEvaluator");
      return (bindingClass != null);
    } catch (ClassNotFoundException e) {
      return false;
    }
  }

  public static boolean isWindows() {
    String os = System.getProperty("os.name");
    return os.startsWith("Windows");
  }

}