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 * DO NOT REMOVE OR ALTER!

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/*

 * 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

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package com.sun.org.apache.xml.internal.dtm.ref;

import com.sun.org.apache.xml.internal.dtm.DTM;

import com.sun.org.apache.xml.internal.dtm.DTMDOMException;

import com.sun.org.apache.xml.internal.dtm.DTMIterator;

import org.w3c.dom.DOMException;

import org.w3c.dom.Node;

import org.w3c.dom.traversal.NodeFilter;

/**

 * <code>DTMNodeIterator</code> gives us an implementation of the

 * DTMNodeIterator which returns DOM nodes.

 *

 * Please note that this is not necessarily equivlaent to a DOM

 * NodeIterator operating over the same document. In particular:

 * <ul>

 *

 * <li>If there are several Text nodes in logical succession (ie,

 * across CDATASection and EntityReference boundaries), we will return

 * only the first; the caller is responsible for stepping through

 * them.

 * (%REVIEW% Provide a convenience routine here to assist, pending

 * proposed DOM Level 3 getAdjacentText() operation?) </li>

 *

 * <li>Since the whole XPath/XSLT architecture assumes that the source

 * document is not altered while we're working with it, we do not

 * promise to implement the DOM NodeIterator's "maintain current

 * position" response to document mutation. </li>

 *

 * <li>Since our design for XPath NodeIterators builds a stateful

 * filter directly into the traversal object, getNodeFilter() is not

 * supported.</li>

 *

 * </ul>

 *

 * <p>State: In progress!!</p>

 * */

public class DTMNodeIterator implements org.w3c.dom.traversal.NodeIterator

{

  private DTMIterator dtm_iter;

  private boolean valid=true;

  //================================================================

  // Methods unique to this class

  /** Public constructor: Wrap a DTMNodeIterator around an existing

   * and preconfigured DTMIterator

   * */

  public DTMNodeIterator(DTMIterator dtmIterator)

    {

      try

      {

        dtm_iter=(DTMIterator)dtmIterator.clone();

      }

      catch(CloneNotSupportedException cnse)

      {

        throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(cnse);

      }

    }

  /** Access the wrapped DTMIterator. I'm not sure whether anyone will

   * need this or not, but let's write it and think about it.

   * */

  public DTMIterator getDTMIterator()

    {

      return dtm_iter;

    }

  //================================================================

  // org.w3c.dom.traversal.NodeFilter API follows

  /** Detaches the NodeIterator from the set which it iterated over,

   * releasing any computational resources and placing the iterator in

   * the INVALID state.

   * */

  public void detach()

    {

      // Theoretically, we could release dtm_iter at this point. But

      // some of the operations may still want to consult it even though

      // navigation is now invalid.

      valid=false;

    }

  /** The value of this flag determines whether the children

   * of entity reference nodes are visible to the iterator.

   *

   * @return false, always (the DTM model flattens entity references)

   * */

  public boolean getExpandEntityReferences()

    {

      return false;

    }

  /** Return a handle to the filter used to screen nodes.

   *

   * This is ill-defined in Xalan's usage of Nodeiterator, where we have

   * built stateful XPath-based filtering directly into the traversal

   * object. We could return something which supports the NodeFilter interface

   * and allows querying whether a given node would be permitted if it appeared

   * as our next node, but in the current implementation that would be very

   * complex -- and just isn't all that useful.

   *

   * @throws DOMException -- NOT_SUPPORTED_ERROR because I can't think

   * of anything more useful to do in this case

   * */

  public NodeFilter getFilter()

    {

      throw new DTMDOMException(DOMException.NOT_SUPPORTED_ERR);

    }

  /** @return The root node of the NodeIterator, as specified

   * when it was created.

   * */

  public Node getRoot()

    {

      int handle=dtm_iter.getRoot();

      return dtm_iter.getDTM(handle).getNode(handle);

    }

  /** Return a mask describing which node types are presented via the

   * iterator.

   **/

  public int getWhatToShow()

    {

      return dtm_iter.getWhatToShow();

    }

  /** @return the next node in the set and advance the position of the

   * iterator in the set.

   *

   * @throws DOMException - INVALID_STATE_ERR Raised if this method is

   * called after the detach method was invoked.

   *  */

  public Node nextNode() throws DOMException

    {

      if(!valid)

        throw new DTMDOMException(DOMException.INVALID_STATE_ERR);

      int handle=dtm_iter.nextNode();

      if (handle==DTM.NULL)

        return null;

      return dtm_iter.getDTM(handle).getNode(handle);

    }

  /** @return the next previous in the set and advance the position of the

   * iterator in the set.

   *

   * @throws DOMException - INVALID_STATE_ERR Raised if this method is

   * called after the detach method was invoked.

   *  */

  public Node previousNode()

    {

      if(!valid)

        throw new DTMDOMException(DOMException.INVALID_STATE_ERR);

      int handle=dtm_iter.previousNode();

      if (handle==DTM.NULL)

        return null;

      return dtm_iter.getDTM(handle).getNode(handle);

    }

}