package org.apache.turbine.util;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  import java.util.Enumeration;
  import java.util.Hashtable;
  import java.util.List;
  
  /***
   * This is where common Object manipulation routines should go.
   *
   * @author <a href="mailto:nissim@nksystems.com">Nissim Karpenstein</a>
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @version $Id: ObjectUtils.java 538432 2007-05-16 05:06:33Z seade $
   */
  public abstract class ObjectUtils
  {
      /***
       * Returns a default value if the object passed is null.
       *
       * @param o The object to test.
       * @param dflt The default value to return.
       * @return The object o if it is not null, dflt otherwise.
       * @deprecated Use org.apache.commons.lang.ObjectUtils.defaultIfNull()
       */
      public static Object isNull(Object o, Object dflt)
      {
  		return org.apache.commons.lang.ObjectUtils.defaultIfNull(o,dflt);
      }
  
      /***
       * Adds an object to a list, making sure the object is in the
       * list only once.
       *
       * @param l The list.
       * @param o The object.
       * @deprecated Use org.apache.commons.collections.SetUniqueList instead.
       */
      public static void addOnce(List l, Object o)
      {
          if (!l.contains(o))
          {
              l.add(o);
          }
      }
  
      /***
       * Converts a hashtable to a byte array for storage/serialization.
       *
       * @param hash The Hashtable to convert.
       *
       * @return A byte[] with the converted Hashtable.
       *
       * @exception Exception A generic exception.
       */
      public static byte[] serializeHashtable(Hashtable hash)
          throws Exception
      {
          Hashtable saveData = new Hashtable(hash.size());
          String key = null;
          Object value = null;
          byte[] byteArray = null;
  
          Enumeration keys = hash.keys();
  
          while (keys.hasMoreElements())
          {
              key = (String) keys.nextElement();
              value = hash.get(key);
              if (value instanceof Serializable)
              {
                  saveData.put (key, value);
              }
          }
 
         ByteArrayOutputStream baos = null;
         BufferedOutputStream bos = null;
         ObjectOutputStream out = null;
         try
         {
             // These objects are closed in the finally.
             baos = new ByteArrayOutputStream();
             bos  = new BufferedOutputStream(baos);
             out  = new ObjectOutputStream(bos);
 
             out.writeObject(saveData);
             out.flush();
             bos.flush();
 
             byteArray = baos.toByteArray();
         }
         finally
         {
             if (out != null)
             {
                 out.close();
             }
             if (bos != null)
             {
                 bos.close();
             }
             if (baos != null)
             {
                 baos.close();
             }
         }
         return byteArray;
     }
 
     /***
      * Deserializes a single object from an array of bytes.
      *
      * @param objectData The serialized object.
      *
      * @return The deserialized object, or <code>null</code> on failure.
      */
     public static Object deserialize(byte[] objectData)
     {
         Object object = null;
 
         if (objectData != null)
         {
             // These streams are closed in finally.
             ObjectInputStream in = null;
             ByteArrayInputStream bin = new ByteArrayInputStream(objectData);
             BufferedInputStream bufin = new BufferedInputStream(bin);
 
             try
             {
                 in = new ObjectInputStream(bufin);
 
                 // If objectData has not been initialized, an
                 // exception will occur.
                 object = in.readObject();
             }
             catch (Exception e)
             {
             }
             finally
             {
                 try
                 {
                     if (in != null)
                     {
                         in.close();
                     }
 
                     bufin.close();
                     bin.close();
                 }
                 catch (IOException e)
                 {
                 }
             }
         }
         return object;
     }
 
     /***
      * Compares two Objects, returns true if their values are the
      * same.  It checks for null values prior to an o1.equals(o2)
      * check
      *
      * @param o1 The first object.
      * @param o2 The second object.
      * @return True if the values of both xstrings are the same.
      * @deprecated Use org.apache.commons.lang.ObjectUtils.equals()
      */
     public static boolean equals(Object o1, Object o2)
     {
 		return org.apache.commons.lang.ObjectUtils.equals(o1,o2);
     }
 
     /***
      * Nice method for adding data to a Hashtable in such a way
      * as to not get NPE's. The point being that if the
      * value is null, Hashtable.put() will throw an exception.
      * That blows in the case of this class cause you may want to
      * essentially treat put("Not Null", null ) == put("Not Null", "")
      * We will still throw a NPE if the key is null cause that should
      * never happen.
      * @deprecated No replacement
      */
     public static final void safeAddToHashtable(Hashtable hash, Object key,
                                                 Object value)
             throws NullPointerException
     {
         if (value == null)
         {
             hash.put(key, "");
         }
         else
         {
             hash.put(key, value);
         }
     }
 }