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46 // This file is not part of the Qt API. It exists purely as an
47 // implementation detail. This header file may change from version to
48 // version without notice, or even be removed.
52 #ifndef Patternist_EmptyIterator_H
53 #define Patternist_EmptyIterator_H
55 #include <private/qabstractxmlforwarditerator_p.h>
56 #include <private/qprimitives_p.h>
66 * @short An QAbstractXmlForwardIterator which always is empty.
68 * EmptyIterator is an QAbstractXmlForwardIterator over the type @c T, which always is empty. Other
69 * iterators can also be empty(or, at least behave as they are empty), but this
70 * class is special designed for this purpose and is therefore fast.
72 * EmptyIterator's constructor is protected, instances is retrieved from CommonValues.
74 * @author Frans Englich <frans.englich@nokia.com>
75 * @ingroup Patternist_iterators
77 template<typename T> class EmptyIterator : public QAbstractXmlForwardIterator<T>
81 * @returns always a default constructed value, T().
89 * @returns always a default constructed value, T().
91 virtual T current() const
99 virtual xsInteger position() const
105 * @returns always @c this, the reverse of <tt>()</tt> is <tt>()</tt>.
107 virtual typename QAbstractXmlForwardIterator<T>::Ptr toReversed()
109 return typename QAbstractXmlForwardIterator<T>::Ptr(const_cast<EmptyIterator<T> *>(this));
115 virtual xsInteger count()
123 virtual typename QAbstractXmlForwardIterator<T>::Ptr copy() const
125 return typename QAbstractXmlForwardIterator<T>::Ptr(const_cast<EmptyIterator *>(this));
129 friend class CommonValues;
134 typename QAbstractXmlForwardIterator<T>::Ptr
137 return typename QAbstractXmlForwardIterator<T>::Ptr(new EmptyIterator<T>());