/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, 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 static ch.qos.logback.core.CoreConstants.JNDI_JAVA_NAMESPACE;
  
  import java.util.Hashtable;
  
  import javax.naming.Context;
  import javax.naming.InitialContext;
  import javax.naming.NamingException;
  
  /**
   * A simple utility class to create and use a JNDI Context.
   *
   * @author Ceki Gülcü
   * @author Michael Osipov
   * @author Sébastien Pennec
   * 
   */
  
  public class JNDIUtil {
  
      static final String RESTRICTION_MSG = "JNDI name must start with " + JNDI_JAVA_NAMESPACE + " but was ";
  
      public static Context getInitialContext() throws NamingException {
          return new InitialContext();
      }
  
      public static Context getInitialContext(Hashtable<?, ?> props) throws NamingException {
          return new InitialContext(props);
      }
  
      public static Object lookupObject(Context ctx, String name) throws NamingException {
          if (ctx == null) {
              return null;
          }
  
          if (OptionHelper.isNullOrEmptyOrAllSpaces(name)) {
              return null;
          }
  
          jndiNameSecurityCheck(name);
  
          Object lookup = ctx.lookup(name);
          return lookup;
      }
  
      public static void jndiNameSecurityCheck(String name) throws NamingException {
          if (!name.startsWith(JNDI_JAVA_NAMESPACE)) {
              throw new NamingException(RESTRICTION_MSG + name);
          }
      }
  
      public static String lookupString(Context ctx, String name) throws NamingException {
          Object lookup = lookupObject(ctx, name);
          return (String) lookup;
      }
  
  }