Source for org.w3c.dom.traversal.TreeWalker

   1: /*
   2:  * Copyright (c) 2000 World Wide Web Consortium,
   3:  * (Massachusetts Institute of Technology, Institut National de
   4:  * Recherche en Informatique et en Automatique, Keio University). All
   5:  * Rights Reserved. This program is distributed under the W3C's Software
   6:  * Intellectual Property License. This program is distributed in the
   7:  * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
   8:  * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
   9:  * PURPOSE.
  10:  * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
  11:  */
  12: 
  13: package org.w3c.dom.traversal;
  14: 
  15: import org.w3c.dom.Node;
  16: import org.w3c.dom.DOMException;
  17: 
  18: /**
  19:  * <code>TreeWalker</code> objects are used to navigate a document tree or
  20:  * subtree using the view of the document defined by their
  21:  * <code>whatToShow</code> flags and filter (if any). Any function which
  22:  * performs navigation using a <code>TreeWalker</code> will automatically
  23:  * support any view defined by a <code>TreeWalker</code>.
  24:  * <p>Omitting nodes from the logical view of a subtree can result in a
  25:  * structure that is substantially different from the same subtree in the
  26:  * complete, unfiltered document. Nodes that are siblings in the
  27:  * <code>TreeWalker</code> view may be children of different, widely
  28:  * separated nodes in the original view. For instance, consider a
  29:  * <code>NodeFilter</code> that skips all nodes except for Text nodes and
  30:  * the root node of a document. In the logical view that results, all text
  31:  * nodes will be siblings and appear as direct children of the root node, no
  32:  * matter how deeply nested the structure of the original document.
  33:  * <p>See also the <a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113'>Document Object Model (DOM) Level 2 Traversal and Range Specification</a>.
  34:  * @since DOM Level 2
  35:  */
  36: public interface TreeWalker {
  37:     /**
  38:      * The <code>root</code> node of the <code>TreeWalker</code>, as specified
  39:      * when it was created.
  40:      */
  41:     public Node getRoot();
  42: 
  43:     /**
  44:      * This attribute determines which node types are presented via the
  45:      * <code>TreeWalker</code>. The available set of constants is defined in
  46:      * the <code>NodeFilter</code> interface.  Nodes not accepted by
  47:      * <code>whatToShow</code> will be skipped, but their children may still
  48:      * be considered. Note that this skip takes precedence over the filter,
  49:      * if any.
  50:      */
  51:     public int getWhatToShow();
  52: 
  53:     /**
  54:      * The filter used to screen nodes.
  55:      */
  56:     public NodeFilter getFilter();
  57: 
  58:     /**
  59:      * The value of this flag determines whether the children of entity
  60:      * reference nodes are visible to the <code>TreeWalker</code>. If false,
  61:      * these children  and their descendants will be rejected. Note that
  62:      * this rejection takes precedence over <code>whatToShow</code> and the
  63:      * filter, if any.
  64:      * <br> To produce a view of the document that has entity references
  65:      * expanded and does not expose the entity reference node itself, use
  66:      * the <code>whatToShow</code> flags to hide the entity reference node
  67:      * and set <code>expandEntityReferences</code> to true when creating the
  68:      * <code>TreeWalker</code>. To produce a view of the document that has
  69:      * entity reference nodes but no entity expansion, use the
  70:      * <code>whatToShow</code> flags to show the entity reference node and
  71:      * set <code>expandEntityReferences</code> to false.
  72:      */
  73:     public boolean getExpandEntityReferences();
  74: 
  75:     /**
  76:      * The node at which the <code>TreeWalker</code> is currently positioned.
  77:      * <br>Alterations to the DOM tree may cause the current node to no longer
  78:      * be accepted by the <code>TreeWalker</code>'s associated filter.
  79:      * <code>currentNode</code> may also be explicitly set to any node,
  80:      * whether or not it is within the subtree specified by the
  81:      * <code>root</code> node or would be accepted by the filter and
  82:      * <code>whatToShow</code> flags. Further traversal occurs relative to
  83:      * <code>currentNode</code> even if it is not part of the current view,
  84:      * by applying the filters in the requested direction; if no traversal
  85:      * is possible, <code>currentNode</code> is not changed.
  86:      */
  87:     public Node getCurrentNode();
  88:     /**
  89:      * The node at which the <code>TreeWalker</code> is currently positioned.
  90:      * <br>Alterations to the DOM tree may cause the current node to no longer
  91:      * be accepted by the <code>TreeWalker</code>'s associated filter.
  92:      * <code>currentNode</code> may also be explicitly set to any node,
  93:      * whether or not it is within the subtree specified by the
  94:      * <code>root</code> node or would be accepted by the filter and
  95:      * <code>whatToShow</code> flags. Further traversal occurs relative to
  96:      * <code>currentNode</code> even if it is not part of the current view,
  97:      * by applying the filters in the requested direction; if no traversal
  98:      * is possible, <code>currentNode</code> is not changed.
  99:      * @exception DOMException
 100:      *   NOT_SUPPORTED_ERR: Raised if an attempt is made to set
 101:      *   <code>currentNode</code> to <code>null</code>.
 102:      */
 103:     public void setCurrentNode(Node currentNode)
 104:                          throws DOMException;
 105: 
 106:     /**
 107:      * Moves to and returns the closest visible ancestor node of the current
 108:      * node. If the search for <code>parentNode</code> attempts to step
 109:      * upward from the <code>TreeWalker</code>'s <code>root</code> node, or
 110:      * if it fails to find a visible ancestor node, this method retains the
 111:      * current position and returns <code>null</code>.
 112:      * @return The new parent node, or <code>null</code> if the current node
 113:      *   has no parent  in the <code>TreeWalker</code>'s logical view.
 114:      */
 115:     public Node parentNode();
 116: 
 117:     /**
 118:      * Moves the <code>TreeWalker</code> to the first visible child of the
 119:      * current node, and returns the new node. If the current node has no
 120:      * visible children, returns <code>null</code>, and retains the current
 121:      * node.
 122:      * @return The new node, or <code>null</code> if the current node has no
 123:      *   visible children  in the <code>TreeWalker</code>'s logical view.
 124:      */
 125:     public Node firstChild();
 126: 
 127:     /**
 128:      * Moves the <code>TreeWalker</code> to the last visible child of the
 129:      * current node, and returns the new node. If the current node has no
 130:      * visible children, returns <code>null</code>, and retains the current
 131:      * node.
 132:      * @return The new node, or <code>null</code> if the current node has no
 133:      *   children  in the <code>TreeWalker</code>'s logical view.
 134:      */
 135:     public Node lastChild();
 136: 
 137:     /**
 138:      * Moves the <code>TreeWalker</code> to the previous sibling of the
 139:      * current node, and returns the new node. If the current node has no
 140:      * visible previous sibling, returns <code>null</code>, and retains the
 141:      * current node.
 142:      * @return The new node, or <code>null</code> if the current node has no
 143:      *   previous sibling.  in the <code>TreeWalker</code>'s logical view.
 144:      */
 145:     public Node previousSibling();
 146: 
 147:     /**
 148:      * Moves the <code>TreeWalker</code> to the next sibling of the current
 149:      * node, and returns the new node. If the current node has no visible
 150:      * next sibling, returns <code>null</code>, and retains the current node.
 151:      * @return The new node, or <code>null</code> if the current node has no
 152:      *   next sibling.  in the <code>TreeWalker</code>'s logical view.
 153:      */
 154:     public Node nextSibling();
 155: 
 156:     /**
 157:      * Moves the <code>TreeWalker</code> to the previous visible node in
 158:      * document order relative to the current node, and returns the new
 159:      * node. If the current node has no previous node,  or if the search for
 160:      * <code>previousNode</code> attempts to step upward from the
 161:      * <code>TreeWalker</code>'s <code>root</code> node,  returns
 162:      * <code>null</code>, and retains the current node.
 163:      * @return The new node, or <code>null</code> if the current node has no
 164:      *   previous node  in the <code>TreeWalker</code>'s logical view.
 165:      */
 166:     public Node previousNode();
 167: 
 168:     /**
 169:      * Moves the <code>TreeWalker</code> to the next visible node in document
 170:      * order relative to the current node, and returns the new node. If the
 171:      * current node has no next node, or if the search for nextNode attempts
 172:      * to step upward from the <code>TreeWalker</code>'s <code>root</code>
 173:      * node, returns <code>null</code>, and retains the current node.
 174:      * @return The new node, or <code>null</code> if the current node has no
 175:      *   next node  in the <code>TreeWalker</code>'s logical view.
 176:      */
 177:     public Node nextNode();
 178: 
 179: }