/*
 * 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.
 */
/*
 * $Id: DTMFilter.java 468653 2006-10-28 07:07:05Z minchau $
 */
package org.apache.xml.dtm;

Simple filter for doing node tests.  Note the semantics of this are
somewhat different that the DOM's NodeFilter.
/**
 * Simple filter for doing node tests.  Note the semantics of this are
 * somewhat different that the DOM's NodeFilter.
 */
public interface DTMFilter
{

  // Constants for whatToShow.  These are used to set the node type that will 
  // be traversed. These values may be ORed together before being passed to
  // the DTMIterator.

  
Show all Nodes.
/**
   * Show all <code>Nodes</code>.
   */
  public static final int SHOW_ALL = 0xFFFFFFFF;

  
Show Element nodes.
/**
   * Show <code>Element</code> nodes.
   */
  public static final int SHOW_ELEMENT = 0x00000001;

  
Show Attr nodes. This is meaningful only when creating an
iterator or tree-walker with an attribute node as its
root; in this case, it means that the attribute node
will appear in the first position of the iteration or traversal.
Since attributes are never children of other nodes, they do not
appear when traversing over the main document tree.
/**
   * Show <code>Attr</code> nodes. This is meaningful only when creating an
   * iterator or tree-walker with an attribute node as its
   * <code>root</code>; in this case, it means that the attribute node
   * will appear in the first position of the iteration or traversal.
   * Since attributes are never children of other nodes, they do not
   * appear when traversing over the main document tree.
   */
  public static final int SHOW_ATTRIBUTE = 0x00000002;

  
Show Text nodes.
/**
   * Show <code>Text</code> nodes.
   */
  public static final int SHOW_TEXT = 0x00000004;

  
Show CDATASection nodes.
/**
   * Show <code>CDATASection</code> nodes.
   */
  public static final int SHOW_CDATA_SECTION = 0x00000008;

  
Show EntityReference nodes. Note that if Entity References
have been fully expanded while the tree was being constructed, these
nodes will not appear and this mask has no effect.
/**
   * Show <code>EntityReference</code> nodes. Note that if Entity References
   * have been fully expanded while the tree was being constructed, these
   * nodes will not appear and this mask has no effect.
   */
  public static final int SHOW_ENTITY_REFERENCE = 0x00000010;

  
Show Entity nodes. This is meaningful only when creating
an iterator or tree-walker with an Entity node as its
root; in this case, it means that the Entity
 node will appear in the first position of the traversal. Since
entities are not part of the document tree, they do not appear when
traversing over the main document tree.
/**
   * Show <code>Entity</code> nodes. This is meaningful only when creating
   * an iterator or tree-walker with an<code> Entity</code> node as its
   * <code>root</code>; in this case, it means that the <code>Entity</code>
   *  node will appear in the first position of the traversal. Since
   * entities are not part of the document tree, they do not appear when
   * traversing over the main document tree.
   */
  public static final int SHOW_ENTITY = 0x00000020;

  
Show ProcessingInstruction nodes.
/**
   * Show <code>ProcessingInstruction</code> nodes.
   */
  public static final int SHOW_PROCESSING_INSTRUCTION = 0x00000040;

  
Show Comment nodes.
/**
   * Show <code>Comment</code> nodes.
   */
  public static final int SHOW_COMMENT = 0x00000080;

  
Show Document nodes. (Of course, as with Attributes
and such, this is meaningful only when the iteration root is the
Document itself, since Document has no parent.)
/**
   * Show <code>Document</code> nodes. (Of course, as with Attributes
   * and such, this is meaningful only when the iteration root is the
   * Document itself, since Document has no parent.)
   */
  public static final int SHOW_DOCUMENT = 0x00000100;

  
Show DocumentType nodes. 
/**
   * Show <code>DocumentType</code> nodes. 
   */
  public static final int SHOW_DOCUMENT_TYPE = 0x00000200;

  
Show DocumentFragment nodes. (Of course, as with
Attributes and such, this is meaningful only when the iteration
root is the Document itself, since DocumentFragment has no parent.)
/**
   * Show <code>DocumentFragment</code> nodes. (Of course, as with
   * Attributes and such, this is meaningful only when the iteration
   * root is the Document itself, since DocumentFragment has no parent.)
   */
  public static final int SHOW_DOCUMENT_FRAGMENT = 0x00000400;

  
Show Notation nodes. This is meaningful only when creating
an iterator or tree-walker with a Notation node as its
root; in this case, it means that the
Notation node will appear in the first position of the
traversal. Since notations are not part of the document tree, they do
not appear when traversing over the main document tree.
/**
   * Show <code>Notation</code> nodes. This is meaningful only when creating
   * an iterator or tree-walker with a <code>Notation</code> node as its
   * <code>root</code>; in this case, it means that the
   * <code>Notation</code> node will appear in the first position of the
   * traversal. Since notations are not part of the document tree, they do
   * not appear when traversing over the main document tree.
   */
  public static final int SHOW_NOTATION = 0x00000800;
  
  
This bit instructs the iterator to show namespace nodes, which are modeled by DTM but not by the DOM. Make sure this does not conflict with NodeFilter. 

%REVIEW% Might be safer to start from higher bits and work down,
to leave room for the DOM to expand its set of constants... Or,
possibly, to create a DTM-specific field for these additional bits.
/**

   * This bit instructs the iterator to show namespace nodes, which
   * are modeled by DTM but not by the DOM.  Make sure this does not
   * conflict with {@link org.w3c.dom.traversal.NodeFilter}.
   * <p>
   * %REVIEW% Might be safer to start from higher bits and work down,
   * to leave room for the DOM to expand its set of constants... Or,
   * possibly, to create a DTM-specific field for these additional bits.
   */
  public static final int SHOW_NAMESPACE = 0x00001000;

  
Special bit for filters implementing match patterns starting with a function. Make sure this does not conflict with NodeFilter. 

%REVIEW% Might be safer to start from higher bits and work down,
to leave room for the DOM to expand its set of constants... Or,
possibly, to create a DTM-specific field for these additional bits.
/**
   * Special bit for filters implementing match patterns starting with
   * a function.  Make sure this does not conflict with
   * {@link org.w3c.dom.traversal.NodeFilter}.
   * <p>
   * %REVIEW% Might be safer to start from higher bits and work down,
   * to leave room for the DOM to expand its set of constants... Or,
   * possibly, to create a DTM-specific field for these additional bits.
   */
  public static final int SHOW_BYFUNCTION = 0x00010000;

  
Test whether a specified node is visible in the logical view of a
DTMIterator. Normally, this function
will be called by the implementation of DTMIterator; 
it is not normally called directly from
user code.
Params:
nodeHandle – int Handle of the node.
whatToShow – one of SHOW_XXX values.
Returns:
one of FILTER_ACCEPT, FILTER_REJECT, or FILTER_SKIP./**
   * Test whether a specified node is visible in the logical view of a
   * <code>DTMIterator</code>. Normally, this function
   * will be called by the implementation of <code>DTMIterator</code>; 
   * it is not normally called directly from
   * user code.
   * 
   * @param nodeHandle int Handle of the node.
   * @param whatToShow one of SHOW_XXX values.
   * @return one of FILTER_ACCEPT, FILTER_REJECT, or FILTER_SKIP.
   */
  public short acceptNode(int nodeHandle, int whatToShow);
  
  
Test whether a specified node is visible in the logical view of a
DTMIterator. Normally, this function
will be called by the implementation of DTMIterator; 
it is not normally called directly from
user code.

TODO: Should this be setNameMatch(expandedName) followed by accept()?
Or will we really be testing a different name at every invocation?
%REVIEW% Under what circumstances will this be used? The cases
I've considered are just as easy and just about as efficient if
the name test is performed in the DTMIterator... -- Joe
%REVIEW% Should that 0xFFFF have a mnemonic assigned to it?
Also: This representation is assuming the expanded name is indeed
split into high/low 16-bit halfwords. If we ever change the
balance between namespace and localname bits (eg because we
decide there are many more localnames than namespaces, which is
fairly likely), this is going to break. It might be safer to
encapsulate the details with a makeExpandedName method and make
that responsible for setting up the wildcard version as well.
Params:
nodeHandle – int Handle of the node.
whatToShow – one of SHOW_XXX values.
expandedName – a value defining the exanded name as defined in 
                    the DTM interface.  Wild cards will be defined 
                    by 0xFFFF in the namespace and/or localname
		 portion of the expandedName.
Returns:
one of FILTER_ACCEPT, FILTER_REJECT, or FILTER_SKIP./**
   * Test whether a specified node is visible in the logical view of a
   * <code>DTMIterator</code>. Normally, this function
   * will be called by the implementation of <code>DTMIterator</code>; 
   * it is not normally called directly from
   * user code.
   * <p>
   * TODO: Should this be setNameMatch(expandedName) followed by accept()?
   * Or will we really be testing a different name at every invocation?
   * 
   * <p>%REVIEW% Under what circumstances will this be used? The cases
   * I've considered are just as easy and just about as efficient if
   * the name test is performed in the DTMIterator... -- Joe</p>
   * 
   * <p>%REVIEW% Should that 0xFFFF have a mnemonic assigned to it?
   * Also: This representation is assuming the expanded name is indeed
   * split into high/low 16-bit halfwords. If we ever change the
   * balance between namespace and localname bits (eg because we
   * decide there are many more localnames than namespaces, which is
   * fairly likely), this is going to break. It might be safer to
   * encapsulate the details with a makeExpandedName method and make
   * that responsible for setting up the wildcard version as well.</p>
   * 
   * @param nodeHandle int Handle of the node.
   * @param whatToShow one of SHOW_XXX values.
   * @param expandedName a value defining the exanded name as defined in 
   *                     the DTM interface.  Wild cards will be defined 
   *                     by 0xFFFF in the namespace and/or localname
   *			 portion of the expandedName.
   * @return one of FILTER_ACCEPT, FILTER_REJECT, or FILTER_SKIP.  */
  public short acceptNode(int nodeHandle, int whatToShow, int expandedName);
 
}