/*
    * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
    *
    * This software is open source.
    * See the bottom of this file for the licence.
    */
   
   package org.dom4j.io;
   
  import org.dom4j.Element;
  import org.dom4j.ElementHandler;
  import org.dom4j.ElementPath;
  
  /***
   * <p>
   * <code>ElementStack</code> is used internally inside the {@link
   * SAXContentHandler} to maintain a stack of {@link Element}instances. It opens
   * an integration possibility allowing derivations to prune the tree when a node
   * is complete.
   * </p>
   * 
   * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
   * @version $Revision: 1.14 $
   */
  class ElementStack implements ElementPath {
      /*** stack of <code>Element</code> objects */
      protected Element[] stack;
  
      /*** index of the item at the top of the stack or -1 if the stack is empty */
      protected int lastElementIndex = -1;
  
      private DispatchHandler handler = null;
  
      public ElementStack() {
          this(50);
      }
  
      public ElementStack(int defaultCapacity) {
          stack = new Element[defaultCapacity];
      }
  
      public void setDispatchHandler(DispatchHandler dispatchHandler) {
          this.handler = dispatchHandler;
      }
  
      public DispatchHandler getDispatchHandler() {
          return this.handler;
      }
  
      /***
       * Peeks at the top element on the stack without changing the contents of
       * the stack.
       */
      public void clear() {
          lastElementIndex = -1;
      }
  
      /***
       * Peeks at the top element on the stack without changing the contents of
       * the stack.
       * 
       * @return the current element on the stack
       */
      public Element peekElement() {
          if (lastElementIndex < 0) {
              return null;
          }
  
          return stack[lastElementIndex];
      }
  
      /***
       * Pops the element off the stack
       * 
       * @return the element that has just been popped off the stack
       */
      public Element popElement() {
          if (lastElementIndex < 0) {
              return null;
          }
  
          return stack[lastElementIndex--];
      }
  
      /***
       * Pushes a new element onto the stack
       * 
       * @param element
       *            DOCUMENT ME!
       */
      public void pushElement(Element element) {
          int length = stack.length;
  
          if (++lastElementIndex >= length) {
              reallocate(length * 2);
          }
  
          stack[lastElementIndex] = element;
      }
 
     /***
      * Reallocates the stack to the given size
      * 
      * @param size
      *            DOCUMENT ME!
      */
     protected void reallocate(int size) {
         Element[] oldStack = stack;
         stack = new Element[size];
         System.arraycopy(oldStack, 0, stack, 0, oldStack.length);
     }
 
     // The ElementPath Interface
     //
     public int size() {
         return lastElementIndex + 1;
     }
 
     public Element getElement(int depth) {
         Element element;
 
         try {
             element = (Element) stack[depth];
         } catch (ArrayIndexOutOfBoundsException e) {
             element = null;
         }
 
         return element;
     }
 
     public String getPath() {
         if (handler == null) {
             setDispatchHandler(new DispatchHandler());
         }
 
         return handler.getPath();
     }
 
     public Element getCurrent() {
         return peekElement();
     }
 
     public void addHandler(String path, ElementHandler elementHandler) {
         this.handler.addHandler(getHandlerPath(path), elementHandler);
     }
 
     public void removeHandler(String path) {
         this.handler.removeHandler(getHandlerPath(path));
     }
 
     /***
      * DOCUMENT ME!
      * 
      * @param path
      *            DOCUMENT ME!
      * 
      * @return true when an <code>ElementHandler</code> is registered for the
      *         specified path.
      */
     public boolean containsHandler(String path) {
         return this.handler.containsHandler(path);
     }
 
     private String getHandlerPath(String path) {
         String handlerPath;
 
         if (this.handler == null) {
             setDispatchHandler(new DispatchHandler());
         }
 
         if (path.startsWith("/")) {
             handlerPath = path;
         } else if (getPath().equals("/")) {
             handlerPath = getPath() + path;
         } else {
             handlerPath = getPath() + "/" + path;
         }
 
         return handlerPath;
     }
 }
 
 /*
  * Redistribution and use of this software and associated documentation
  * ("Software"), with or without modification, are permitted provided that the
  * following conditions are met:
  * 
  * 1. Redistributions of source code must retain copyright statements and
  * notices. Redistributions must also contain a copy of this document.
  * 
  * 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 name "DOM4J" must not be used to endorse or promote products derived
  * from this Software without prior written permission of MetaStuff, Ltd. For
  * written permission, please contact dom4j-info@metastuff.com.
  * 
  * 4. Products derived from this Software may not be called "DOM4J" nor may
  * "DOM4J" appear in their names without prior written permission of MetaStuff,
  * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
  * 
  * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
  * 
  * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``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 METASTUFF, LTD. 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.
  * 
  * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
  */