Syndication::Mapper Class

Detailed Description

The type of this "something else" is specified by the template parameter T.

In the default implementation it is used with the Feed interface, but it is not limited to that. T can be an arbitrary class.

There are three (advanced and hopefully rare) use cases that require you to implement your own mapper. For more information on the possible uses, see TODO: link docs.

1) Add your own feed parser. In case you need support for another feed format (Okay! News, CDF, completely backward-incompatible Atom 5.0, you name it), you can implement AbstractParser and SpecificDocument for it and provide a Mapper<Feed>

class OkayNewsMapper : public Mapper<Feed>
{
    public:

    virtual FeedPtr map(SpecificDocumentPtr doc) const { ... }
};

parserCollection()->registerParser(new OkayNews::Parser, new OkayNewsMapper);

2) Implement your own mapper for the Feed abstraction, for an existing parser. E.g. if you think Syndication does map Atom all wrong, you can implement your own Atom mapper and use that instead of the default one.

class MyAtomMapper : public Mapper<Feed>
{
    public:

    virtual FeedPtr map(SpecificDocumentPtr doc) const { ... }
};

parserCollection()->changeMapper("atom", new MyAtomMapper);

3) Use your own abstraction. In case the Feed interface does not fit your needs, you can use your own interface, let's say "MyFeed". Be aware you have to implement custom mappings for all feed formats then:

class MyFeed
{
    public:

    QString title() const; // my special title
    QList<Article> articles() const; // I name it articles
};

class MyAtomMapper : public Mapper<MyFeed> { ... };
class MyRDFMapper : public Mapper<MyFeed> { ... };
class MyRSS2Mapper : public Mapper<MyFeed> { ... };

ParserCollection<MyFeed>* coll = new ParserCollection<MyFeed>;
coll->registerParser(new Atom::Parser, new MyAtomMapper);
coll->registerParser(new RDF::Parser, new MyRDFMapper);
coll->registerParser(new RSS2::Parser, new MyRSS2Mapper);