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Posted to dev@turbine.apache.org by "Henning P. Schmiedehausen" <ma...@hometree.net> on 2001/06/01 16:18:52 UTC

SequencedHashtable

Hi,

I might be wrong, but this looks bogus to me in SequencedHashtable.

/**
 * Slightly cheaper implementation of <code>values()</code> method.
 */
public Collection values ()
{
    return keySequence;
}

because in keySequence are the keys stored. This would be some sort
of 

public List keyList()
{
    return keySequence;
}


A demo program seems to confirm this:

--- cut ---
import java.util.Hashtable;
import java.util.Iterator;

import org.apache.turbine.util.SequencedHashtable;

public class sequencetest
{
  public static void main(String[] args)
  {
    Hashtable ht = new Hashtable();
    SequencedHashtable sht = new SequencedHashtable();

    for(int i = 0; i < 10; i++)
    {
      ht.put("Key "+Integer.toString(i), "Value "+Integer.toString(i));
      sht.put("Key "+Integer.toString(i), "Value "+Integer.toString(i));
    }

    Iterator it;

    System.out.println("Hashtable:");
    it = ht.values().iterator();

    while(it.hasNext())
      System.out.println(it.next());

    System.out.println("Seq.Hashtable:");
    it = sht.values().iterator();

    while(it.hasNext())
      System.out.println(it.next());
  }
}
--- cut ---

Hashtable:
Value 4
Value 3
Value 2
Value 1
Value 0
Value 9
Value 8
Value 7
Value 6
Value 5

Seq.Hashtable:
Key 0
Key 1
Key 2
Key 3
Key 4
Key 5
Key 6
Key 7
Key 8
Key 9

Not the same. Patch attached. I thought about deprecation but removing
the values() method makes the original method from Hashtable visible
again which is a good thing.

By applying this patch, the whole SequencedHashtable shebang suddently
gets usable for me to replace lots of "keep list and hashtable around"
situations. ;-)

	Regards
		Henning

Index: SequencedHashtable.java
===================================================================
RCS file: /home/cvspublic/jakarta-turbine/src/java/org/apache/turbine/util/SequencedHashtable.java,v
retrieving revision 1.4
diff -u -r1.4 SequencedHashtable.java
--- SequencedHashtable.java	2001/05/20 02:38:52	1.4
+++ SequencedHashtable.java	2001/06/01 14:18:09
@@ -57,6 +57,7 @@
 import java.util.Collection;
 import java.util.Hashtable;
 import java.util.Iterator;
+import java.util.List;
 import java.util.LinkedList;
 import java.util.Map;
 import java.util.Set;
@@ -73,6 +74,7 @@
  * the use of a list of <code>Map.Entry</code> objects.
  *
  * @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
+ * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
  * @version $Id: SequencedHashtable.java,v 1.4 2001/05/20 02:38:52 dlr Exp $
  */
 public class SequencedHashtable extends Hashtable
@@ -261,10 +263,14 @@
     }
 
     /**
-     * Slightly cheaper implementation of <code>values()</code> method.
+     * Returns the keys in the table as a List.
+     *
+     * @return    List of all keys
      */
-    public Collection values ()
+  
+    public List keyList()
     {
         return keySequence;
     }
+
 }
-- 
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen       -- Geschaeftsfuehrer
INTERMETA - Gesellschaft fuer Mehrwertdienste mbH     hps@intermeta.de

Am Schwabachgrund 22  Fon.: 09131 / 50654-0   info@intermeta.de
D-91054 Buckenhof     Fax.: 09131 / 50654-20   

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