dtmdefaultbaseiterators.java

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/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed 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: DTMDefaultBaseIterators.java,v 1.2.4.1 2005/09/15 08:15:00 suresh_emailid Exp $
 */
package com.sun.org.apache.xml.internal.dtm.ref;

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

import javax.xml.transform.Source;

import com.sun.org.apache.xml.internal.utils.XMLStringFactory;

import com.sun.org.apache.xml.internal.res.XMLErrorResources;
import com.sun.org.apache.xml.internal.res.XMLMessages;
import com.sun.org.apache.xalan.internal.xsltc.dom.NodeCounter;

/**
 * This class implements the traversers for DTMDefaultBase.
 */
public abstract class DTMDefaultBaseIterators extends DTMDefaultBaseTraversers
{

  /**
   * Construct a DTMDefaultBaseTraversers object from a DOM node.
   *
   * @param mgr The DTMManager who owns this DTM.
   * @param source The object that is used to specify the construction source.
   * @param dtmIdentity The DTM identity ID for this DTM.
   * @param whiteSpaceFilter The white space filter for this DTM, which may
   *                         be null.
   * @param xstringfactory The factory to use for creating XMLStrings.
   * @param doIndexing true if the caller considers it worth it to use 
   *                   indexing schemes.
   */
  public DTMDefaultBaseIterators(DTMManager mgr, Source source,
                                 int dtmIdentity,
                                 DTMWSFilter whiteSpaceFilter,
                                 XMLStringFactory xstringfactory,
                                 boolean doIndexing)
  {
    super(mgr, source, dtmIdentity, whiteSpaceFilter, 
          xstringfactory, doIndexing);
  }

  /**
   * Construct a DTMDefaultBaseTraversers object from a DOM node.
   *
   * @param mgr The DTMManager who owns this DTM.
   * @param source The object that is used to specify the construction source.
   * @param dtmIdentity The DTM identity ID for this DTM.
   * @param whiteSpaceFilter The white space filter for this DTM, which may
   *                         be null.
   * @param xstringfactory The factory to use for creating XMLStrings.
   * @param doIndexing true if the caller considers it worth it to use 
   *                   indexing schemes.
   * @param blocksize The block size of the DTM.
   * @param usePrevsib true if we want to build the previous sibling node array.
   * @param newNameTable true if we want to use a new ExpandedNameTable for this DTM.
   */
  public DTMDefaultBaseIterators(DTMManager mgr, Source source,
                                 int dtmIdentity,
                                 DTMWSFilter whiteSpaceFilter,
                                 XMLStringFactory xstringfactory,
                                 boolean doIndexing,
                                 int blocksize,
                                 boolean usePrevsib,
                                 boolean newNameTable)
  {
    super(mgr, source, dtmIdentity, whiteSpaceFilter, 
          xstringfactory, doIndexing, blocksize, usePrevsib, newNameTable);
  }

  /**
   * Get an iterator that can navigate over an XPath Axis, predicated by
   * the extended type ID.
   * Returns an iterator that must be initialized
   * with a start node (using iterator.setStartNode()).
   *
   * @param axis One of Axes.ANCESTORORSELF, etc.
   * @param type An extended type ID.
   *
   * @return A DTMAxisIterator, or null if the given axis isn't supported.
   */
  public DTMAxisIterator getTypedAxisIterator(int axis, int type)
  {

    DTMAxisIterator iterator = null;

    /* This causes an error when using patterns for elements that
       do not exist in the DOM (translet types which do not correspond
       to a DOM type are mapped to the DOM.ELEMENT type).
    */

    //        if (type == NO_TYPE) {
    //            return(EMPTYITERATOR);
    //        }
    //        else if (type == ELEMENT) {
    //            iterator = new FilterIterator(getAxisIterator(axis),
    //                                          getElementFilter());
    //        }
    //        else 
    {
      switch (axis)
      {
      case Axis.SELF :
        iterator = new TypedSingletonIterator(type);
        break;
      case Axis.CHILD :
        iterator = new TypedChildrenIterator(type);
        break;
      case Axis.PARENT :
        return (new ParentIterator().setNodeType(type));
      case Axis.ANCESTOR :
        return (new TypedAncestorIterator(type));
      case Axis.ANCESTORORSELF :
        return ((new TypedAncestorIterator(type)).includeSelf());
      case Axis.ATTRIBUTE :
        return (new TypedAttributeIterator(type));
      case Axis.DESCENDANT :
        iterator = new TypedDescendantIterator(type);
        break;
      case Axis.DESCENDANTORSELF :
        iterator = (new TypedDescendantIterator(type)).includeSelf();
        break;
      case Axis.FOLLOWING :
        iterator = new TypedFollowingIterator(type);
        break;
      case Axis.PRECEDING :
        iterator = new TypedPrecedingIterator(type);
        break;
      case Axis.FOLLOWINGSIBLING :
        iterator = new TypedFollowingSiblingIterator(type);
        break;
      case Axis.PRECEDINGSIBLING :
        iterator = new TypedPrecedingSiblingIterator(type);
        break;
      case Axis.NAMESPACE :
        iterator = new TypedNamespaceIterator(type);
        break;
      case Axis.ROOT :
        iterator = new TypedRootIterator(type);
        break;
      default :
        throw new DTMException(XMLMessages.createXMLMessage(
            XMLErrorResources.ER_TYPED_ITERATOR_AXIS_NOT_IMPLEMENTED, 
            new Object[]{Axis.getNames(axis)})); 
            //"Error: typed iterator for axis "
                               //+ Axis.names[axis] + "not implemented");
      }
    }

    return (iterator);
  }

  /**
   * This is a shortcut to the iterators that implement the
   * XPath axes.
   * Returns a bare-bones iterator that must be initialized
   * with a start node (using iterator.setStartNode()).
   *
   * @param axis One of Axes.ANCESTORORSELF, etc.
   *
   * @return A DTMAxisIterator, or null if the given axis isn't supported.
   */
  public DTMAxisIterator getAxisIterator(final int axis)
  {

    DTMAxisIterator iterator = null;

    switch (axis)
    {
    case Axis.SELF :
      iterator = new SingletonIterator();
      break;
    case Axis.CHILD :
      iterator = new ChildrenIterator();
      break;
    case Axis.PARENT :
      return (new ParentIterator());
    case Axis.ANCESTOR :
      return (new AncestorIterator());
    case Axis.ANCESTORORSELF :
      return ((new AncestorIterator()).includeSelf());
    case Axis.ATTRIBUTE :
      return (new AttributeIterator());
    case Axis.DESCENDANT :
      iterator = new DescendantIterator();
      break;
    case Axis.DESCENDANTORSELF :
      iterator = (new DescendantIterator()).includeSelf();
      break;
    case Axis.FOLLOWING :
      iterator = new FollowingIterator();
      break;
    case Axis.PRECEDING :
      iterator = new PrecedingIterator();
      break;
    case Axis.FOLLOWINGSIBLING :
      iterator = new FollowingSiblingIterator();
      break;
    case Axis.PRECEDINGSIBLING :
      iterator = new PrecedingSiblingIterator();
      break;
    case Axis.NAMESPACE :
      iterator = new NamespaceIterator();
      break;
    case Axis.ROOT :
      iterator = new RootIterator();
      break;
    default :
      throw new DTMException(XMLMessages.createXMLMessage(
        XMLErrorResources.ER_ITERATOR_AXIS_NOT_IMPLEMENTED, 
        new Object[]{Axis.getNames(axis)})); 
        //"Error: iterator for axis '" + Axis.names[axis]
                             //+ "' not implemented");
    }

    return (iterator);
  }

  /**
   * Abstract superclass defining behaviors shared by all DTMDefault's
   * internal implementations of DTMAxisIterator. Subclass this (and
   * override, if necessary) to implement the specifics of an
   * individual axis iterator.
   *
   * Currently there isn't a lot here
   */
  public abstract class InternalAxisIteratorBase extends DTMAxisIteratorBase
  {

    // %REVIEW% We could opt to share _nodeType and setNodeType() as
    // well, and simply ignore them in iterators which don't use them.
    // But Scott's worried about the overhead involved in cloning
    // these, and wants them to have as few fields as possible. Note
    // that we can't create a TypedInternalAxisIteratorBase because
    // those are often based on the untyped versions and Java doesn't
    // support multiple inheritance. <sigh/>

    /**
     * Current iteration location. Usually this is the last location
     * returned (starting point for the next() search); for single-node
     * iterators it may instead be initialized to point to that single node.
     */
    protected int _currentNode;

    /**
     * Remembers the current node for the next call to gotoMark().
     *
     * %REVIEW% Should this save _position too?
     */
    public void setMark()
    {
      _markedNode = _currentNode;
    }

    /**
     * Restores the current node remembered by setMark().
     *
     * %REVEIW% Should this restore _position too?
     */
    public void gotoMark()
    {
      _currentNode = _markedNode;
    }
        
  }  // end of InternalAxisIteratorBase 

  /**
   * Iterator that returns all immediate children of a given node
   */
  public final class ChildrenIterator extends InternalAxisIteratorBase
  {

    /**
     * Setting start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * If the iterator is not restartable, this has no effect.
     * %REVIEW% Should it return/throw something in that case,
     * or set current node to END, to indicate request-not-honored?
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {
//%HZ%: Added reference to DTMDefaultBase.ROOTNODE back in, temporarily
      if (node == DTMDefaultBase.ROOTNODE)
        node = getDocument();
      if (_isRestartable)
      {
        _startNode = node;
        _currentNode = (node == DTM.NULL) ? DTM.NULL
                                          : _firstch(makeNodeIdentity(node));

        return resetPosition();
      }

      return this;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END if no more
     * are available.
     */
    public int next()
    {
      if (_currentNode != NULL) {
        int node = _currentNode;
        _currentNode = _nextsib(node);
        return returnNode(makeNodeHandle(node));
      }

      return END;
    }
  }  // end of ChildrenIterator

  /**
   * Iterator that returns the parent of a given node. Note that
   * this delivers only a single node; if you want all the ancestors,
   * see AncestorIterator.
   */
  public final class ParentIterator extends InternalAxisIteratorBase
  {

    /** The extended type ID that was requested. */
    private int _nodeType = -1;

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {
//%HZ%: Added reference to DTMDefaultBase.ROOTNODE back in, temporarily
      if (node == DTMDefaultBase.ROOTNODE)
        node = getDocument();
      if (_isRestartable)
      {
        _startNode = node;
        _currentNode = getParent(node);

        return resetPosition();
      }

      return this;
    }

    /**
     * Set the node type of the parent that we're looking for.
     * Note that this does _not_ mean "find the nearest ancestor of
     * this type", but "yield the parent if it is of this type".
     *
     *
     * @param type extended type ID.
     *
     * @return ParentIterator configured with the type filter set.
     */
    public DTMAxisIterator setNodeType(final int type)
    {

      _nodeType = type;

      return this;
    }

    /**
     * Get the next node in the iteration. In this case, we return
     * only the immediate parent, _if_ it matches the requested nodeType.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {
      int result = _currentNode;

      if (_nodeType >= DTM.NTYPES) {
        if (_nodeType != getExpandedTypeID(_currentNode)) {
          result = END;
        }
      } else if (_nodeType != NULL) {
        if (_nodeType != getNodeType(_currentNode)) {
          result = END;
        }
      }

      _currentNode = END;

      return returnNode(result);
    }
  }  // end of ParentIterator

  /**
   * Iterator that returns children of a given type for a given node.
   * The functionality chould be achieved by putting a filter on top
   * of a basic child iterator, but a specialised iterator is used
   * for efficiency (both speed and size of translet).
   */
  public final class TypedChildrenIterator extends InternalAxisIteratorBase
  {

    /** The extended type ID that was requested. */
    private final int _nodeType;

    /**
     * Constructor TypedChildrenIterator
     *
     *
     * @param nodeType The extended type ID being requested.
     */
    public TypedChildrenIterator(int nodeType)
    {
      _nodeType = nodeType;
    }

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {
//%HZ%: Added reference to DTMDefaultBase.ROOTNODE back in, temporarily
      if (node == DTMDefaultBase.ROOTNODE)
        node = getDocument();
      if (_isRestartable)
      {
        _startNode = node;
        _currentNode = (node == DTM.NULL)
                                   ? DTM.NULL
                                   : _firstch(makeNodeIdentity(_startNode));

        return resetPosition();
      }

      return this;
    }

    /**
     * Get the next node in the iteration.
     *
     * @return The next node handle in the iteration, or END.
     */
    public int next()
    {
      int eType;
      int node = _currentNode;

      int nodeType = _nodeType;

      if (nodeType >= DTM.NTYPES) {
        while (node != DTM.NULL && _exptype(node) != nodeType) {
          node = _nextsib(node);
        }
      } else {
        while (node != DTM.NULL) {
          eType = _exptype(node);
          if (eType < DTM.NTYPES) {
            if (eType == nodeType) {
              break;
            }
          } else if (m_expandedNameTable.getType(eType) == nodeType) {
            break;
          }
          node = _nextsib(node);
        }
      }

      if (node == DTM.NULL) {
        _currentNode = DTM.NULL;
        return DTM.NULL;
      } else {
        _currentNode = _nextsib(node);
        return returnNode(makeNodeHandle(node));
      }

    }
  }  // end of TypedChildrenIterator

  /**
   * Iterator that returns children within a given namespace for a
   * given node. The functionality chould be achieved by putting a
   * filter on top of a basic child iterator, but a specialised
   * iterator is used for efficiency (both speed and size of translet).
   */
  public final class NamespaceChildrenIterator
          extends InternalAxisIteratorBase
  {

    /** The extended type ID being requested. */
    private final int _nsType;

    /**
     * Constructor NamespaceChildrenIterator
     *
     *
     * @param type The extended type ID being requested.
     */
    public NamespaceChildrenIterator(final int type)
    {
      _nsType = type;
    }

    /**
     * Set start to END should 'close' the iterator,
     * i.e. subsequent call to next() should return END.
     *
     * @param node Sets the root of the iteration.
     *
     * @return A DTMAxisIterator set to the start of the iteration.
     */
    public DTMAxisIterator setStartNode(int node)
    {
//%HZ%: Added reference to DTMDefaultBase.ROOTNODE back in, temporarily
      if (node == DTMDefaultBase.ROOTNODE)
        node = getDocument();
      if (_isRestartable)
      {
        _startNode = node;
        _currentNode = (node == DTM.NULL) ? DTM.NULL : NOTPROCESSED;

        return resetPosition();
      }