source: trunk/src/xmlpatterns/iterators/qsequencemappingiterator_p.h@ 604

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//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.

#ifndef Patternist_SequenceMappingIterator_H
#define Patternist_SequenceMappingIterator_H

#include "qabstractxmlforwarditerator_p.h"
#include "qdynamiccontext_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist
{
    /**
     * @short Proxies another QAbstractXmlForwardIterator, and for each item, returns the
     * Sequence returned from a mapping function.
     *
     * ItemMappingIterator is practical when the items in an QAbstractXmlForwardIterator needs to
     * be translated to another sequence, while still doing it in a pipe-lined
     * fashion. In contrast to ItemMappingIterator, SequenceMappingIterator maps
     * each item into another QAbstractXmlForwardIterator, and where the SequenceMappingIterator's own
     * result is the concatenation of all those Iterators. Hence, while ItemMappingIterator
     * is better tailored for one-to-one or one-to-zero conversion, SequenceMappingIterator
     * is more suitable for one-to-many conversion.
     *
     * This is achieved by that SequenceMappingIterator's constructor takes
     * an instance of a class, that must have the following member:
     *
     * @code
     * QAbstractXmlForwardIterator<TResult>::Ptr mapToSequence(const TSource::Ptr &item,
     *                                                      const DynamicContext::Ptr &context) const;
     * @endcode
     *
     * @author Frans Englich <[email protected]>
     * @see ItemMappingIterator
     * @ingroup Patternist_iterators
     */
    template<typename TResult, typename TSource, typename TMapper>
    class SequenceMappingIterator : public QAbstractXmlForwardIterator<TResult>
    {
    public:
        /**
         * Constructs a SequenceMappingIterator.
         *
         * @param mapper the object that has the mapToItem() sequence.
         * @param sourceIterator the QAbstractXmlForwardIterator whose items should be mapped.
         * @param context the DynamicContext that will be passed to the map function.
         * May be null.
         */
        SequenceMappingIterator(const TMapper &mapper,
                                const typename QAbstractXmlForwardIterator<TSource>::Ptr &sourceIterator,
                                const DynamicContext::Ptr &context);

        virtual TResult next();
        virtual xsInteger count();
        virtual TResult current() const;
        virtual xsInteger position() const;

        /**
         * The reason the implementation is placed in line here, is due to a bug
         * in MSVC-2005 version 14.00.50727.762. Note that it works with version 14.00.50727.42.
         */
        virtual typename QAbstractXmlForwardIterator<TResult>::Ptr copy() const
        {
            return typename QAbstractXmlForwardIterator<TResult>::Ptr
                    (new SequenceMappingIterator<TResult, TSource, TMapper>(m_mapper,