diff --git a/src/java/org/apache/commons/collections/StringStack.java b/src/java/org/apache/commons/collections/StringStack.java
new file mode 100644
index 000000000..dd6d252f5
--- /dev/null
+++ b/src/java/org/apache/commons/collections/StringStack.java
@@ -0,0 +1,259 @@
+package org.apache.commons.collections;
+
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2001 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution,
+ *    if any, must include the following acknowledgment:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowledgment may appear in the software itself,
+ *    if and wherever such third-party acknowledgments normally appear.
+ *
+ * 4. The names "Apache" and "Apache Software Foundation" and 
+ *    "Apache Turbine" must not be used to endorse or promote products 
+ *    derived from this software without prior written permission. For 
+ *    written permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache",
+ *    "Apache Turbine", nor may "Apache" appear in their name, without 
+ *    prior written permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+import java.io.Serializable;
+import java.util.Iterator;
+import java.util.Stack;
+
+/**
+ * This class implements a stack for String objects.
+ *
+ * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
+ * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
+ * @version $Id: StringStack.java,v 1.1 2002/02/23 03:52:02 bayard Exp $
+ */
+public class StringStack implements Serializable
+{
+    /**
+     * The stack of <code>String</code> objects.
+     */
+    private Stack stack = null;
+
+    /**
+     * Creates an empty instance.
+     */
+    public StringStack()
+    {
+        stack = new Stack();
+    }
+
+    /**
+     * Adds the String to the collection if it does not already
+     * contain it.
+     *
+     * @param s The <code>String</code> object to add to this stack
+     * (if it is not <code>null</code> and doesn't already exist in
+     * the stack).
+     * @return A reference to this stack (useful for when this method
+     * is called repeatedly).
+     */
+    public StringStack add(String s)
+    {
+        if (s != null && !contains(s))
+        {
+            stack.push(s);
+        }
+        return this;
+    }
+
+    /**
+     * Adds all Strings in the given StringStack to the collection
+     * (skipping those it already contains)
+     *
+     * @param ss The stack of <code>String</code> objects to add to
+     * this stack (if it is not <code>null</code> and doesn't already
+     * exist in the stack).
+     * @return A reference to this stack (useful for when this method
+     * is called repeatedly).
+     */
+    public StringStack addAll(StringStack ss)
+    {
+        Iterator i = ss.stack.iterator();
+        while (i.hasNext())
+        {
+            add((String) i.next());
+        }
+        return this;
+    }
+
+    /**
+     * Clears the stack.
+     */
+    public void clear()
+    {
+        stack.clear();
+    }
+    
+    /**
+     * Returns whether this stack contain the specified text.
+     *
+     * @param s The text to search for.
+     * @return Whether the stack contains the text.
+     */
+    public boolean contains(String s)
+    {
+        return (stack.search(s) != -1);
+    }
+
+    /**
+     * Whether the stack is empty.
+     *
+     * @return Whether the stack is empty.
+     */
+    public final boolean empty()
+    {
+        return stack.empty();
+    }
+
+    /**
+     * Get a string off the stack at a certain position.
+     *
+     * @param i The position.
+     * @return A the string from the specified position.
+     */
+    public String get(int i)
+    {
+        return (String) stack.elementAt(i);
+    }
+
+    /**
+     * Returns the size of the stack.
+     *
+     * @return The size of the stack.
+     */
+    public final int size()
+    {
+        return stack.size();
+    }
+
+    /**
+     * Converts the stack to a single {@link java.lang.String} with no
+     * separator.
+     *
+     * @return The stack elements as a single block of text.
+     */
+    public String toString()
+    {
+        return toString("");
+    }
+
+    /**
+     * Converts the stack to a single {@link java.lang.String}.
+     *
+     * @param separator The text to use as glue between elements in
+     * the stack.
+     * @return The stack elements--glued together by
+     * <code>separator</code>--as a single block of text.
+     */
+    public String toString( String separator )
+    {
+        String s;
+        if (size() > 0)
+        {
+            if ( separator == null )
+            {
+                separator = "";
+            }
+ 
+            // Determine what size to pre-allocate for the buffer.
+            int totalSize = 0;
+            for (int i = 0; i < stack.size(); i++)
+            {
+                totalSize += get(i).length();
+            }
+            totalSize += (stack.size() - 1) * separator.length();
+
+            StringBuffer sb = new StringBuffer(totalSize).append( get(0) );
+            for (int i = 1; i < stack.size(); i++)
+            {
+                sb.append(separator).append(get(i));
+            }
+            s = sb.toString();
+        }
+        else
+        {
+            s = "";
+        }
+        return s;
+    }
+
+    /**
+     * Compares two StringStacks.  Considered equal if the
+     * <code>toString()</code> method returns such.
+     */
+    public boolean equals(Object ssbuf)
+    {
+        boolean isEquiv = false;
+        if ( ssbuf == null || !(ssbuf instanceof StringStack) ) 
+        {
+            isEquiv = false;
+        }
+        else if ( ssbuf == this ) 
+        {
+            isEquiv = true;
+        }
+        else if ( this.toString().equals(ssbuf.toString()) )
+        {
+            isEquiv = true;
+        }
+        return isEquiv;
+    }
+
+    /**
+     * Turns this stack into an array.
+     *
+     * @return This stack as an array.
+     */
+    public String[] toStringArray()
+    {
+        String[] array = new String[size()];
+        for (int i = 0; i < size(); i++)
+        {
+            array[i] = get(i);
+        }
+        return array;
+    }
+}