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//
// NodeIterator.h
//
// Library: XML
// Package: DOM
// Module: NodeIterator
//
// Definition of the DOM NodeIterator class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef DOM_NodeIterator_INCLUDED
#define DOM_NodeIterator_INCLUDED
#include "Poco/XML/XML.h"
namespace Poco {
namespace XML {
class Node;
class NodeFilter;
class XML_API NodeIterator
/// Iterators are used to step through a set of nodes, e.g. the set of nodes
/// in a NodeList, the document subtree governed by a particular Node, the results
/// of a query, or any other set of nodes. The set of nodes to be iterated is
/// determined by the implementation of the NodeIterator. DOM Level 2 specifies
/// a single NodeIterator implementation for document-order traversal of a document
/// subtree.
///
/// A NodeIterator can be directly instantiated using one of its constructors -
/// the DocumentTraversal interface is not needed and therefore not implemented.
/// Unlike most other DOM classes, NodeIterator supports value semantics.
///
/// If the NodeIterator's current node is removed from the document, the
/// result of calling any of the movement methods is undefined. This behavior does
/// not conform to the DOM Level 2 Traversal specification.
{
public:
NodeIterator(Node* root, unsigned long whatToShow, NodeFilter* pFilter = 0);
/// Creates a NodeIterator over the subtree rooted at the specified node.
NodeIterator(const NodeIterator& iterator);
/// Creates a NodeIterator by copying another NodeIterator.
NodeIterator& operator = (const NodeIterator& iterator);
/// Assignment operator.
~NodeIterator();
/// Destroys the NodeIterator.
Node* root() const;
/// The root node of the NodeIterator, as specified when it was created.
unsigned long whatToShow() const;
/// This attribute determines which node types are presented via the iterator.
/// The available set of constants is defined in the NodeFilter interface.
/// Nodes not accepted by whatToShow will be skipped, but their children may
/// still be considered. Note that this skip takes precedence over the filter,
/// if any.
NodeFilter* filter() const;
/// The NodeFilter used to screen nodes.
bool expandEntityReferences() const;
/// The value of this flag determines whether the children of entity reference
/// nodes are visible to the iterator. If false, they and their descendants
/// will be rejected. Note that this rejection takes precedence over whatToShow
/// and the filter. Also note that this is currently the only situation where
/// NodeIterators may reject a complete subtree rather than skipping individual
/// nodes.
///
/// To produce a view of the document that has entity references expanded and
/// does not expose the entity reference node itself, use the whatToShow flags
/// to hide the entity reference node and set expandEntityReferences to true
/// when creating the iterator. To produce a view of the document that has entity
/// reference nodes but no entity expansion, use the whatToShow flags to show
/// the entity reference node and set expandEntityReferences to false.
///
/// This implementation does not support entity reference expansion and
/// thus always returns false.
Node* nextNode();
/// Returns the next node in the set and advances the position of the iterator
/// in the set. After a NodeIterator is created, the first call to nextNode()
/// returns the first node in the set.
Node* previousNode();
/// Returns the previous node in the set and moves the position of the NodeIterator
/// backwards in the set.
Node* currentNodeNP() const;
/// Returns the current node in the set.
///
/// Leaves the NodeIterator unchanged.
///
/// Warning: This is a proprietary extension to the DOM Level 2 NodeIterator
/// interface.
void detach();
/// Detaches the NodeIterator from the set which it iterated over, releasing
/// any computational resources and placing the iterator in the INVALID state.
/// After detach has been invoked, calls to nextNode or previousNode will raise
/// the exception INVALID_STATE_ERR.
protected:
bool accept(Node* pNode) const;
Node* next() const;
Node* previous() const;
Node* last();
private:
NodeIterator();
Node* _pRoot;
unsigned long _whatToShow;
NodeFilter* _pFilter;
Node* _pCurrent;
};
//
// inlines
//
inline Node* NodeIterator::root() const
{
return _pRoot;
}
inline Node* NodeIterator::currentNodeNP() const
{
return _pCurrent;
}
inline unsigned long NodeIterator::whatToShow() const
{
return _whatToShow;
}
inline NodeFilter* NodeIterator::filter() const
{
return _pFilter;
}
inline bool NodeIterator::expandEntityReferences() const
{
return false;
}
} } // namespace Poco::XML
#endif // DOM_NodeIterator_INCLUDED
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