Improve the documentation of Collection

[libs/datafile.git] / source / collection.h

diff --git a/source/collection.h b/source/collection.h
index b2239905edb4d824cd14e1d763ff62d234672032..5dd2fe67ff2769083532605e2b33bd5fe3c9dec1 100644 (file)
--- a/source/collection.h
+++ b/source/collection.h
@@ -34,12 +34,17 @@ class CollectionItemType;
 /**
 A collection of objects that can be loaded from a datafile.  Each object is
 identified by a name, which must be unique across the entire collection.
+
+While this class can be instantiated by itself and used for storing objects,
+loading requires that a subclass defines the supported types.  See the add_type
+method for details.
 */
 class Collection
 {
 public:
        /**
-       Loads objects into a Collection.
+       Loads objects into a Collection.  Automatically picks up keywords from
+       defined item types.
        */
        class Loader: public DataFile::Loader
        {
@@ -87,10 +92,8 @@ public:
        Collection() { }
        virtual ~Collection();
 
-       /**
-       Adds an object into the collection.  If a name collision occurs, an
-       exception is thrown.  The collection takes ownership of the object.
-       */
+       /** Adds an object into the collection.  The name must not pre-exist.  The
+       collection takes ownership of the object. */
        template<typename T>
        void add(const std::string &name, T *item)
        {
@@ -110,9 +113,7 @@ public:
                }
        }
 
-       /**
-       Gets an object of a specific type from the collection.
-       */
+       /// Gets a typed object from the collection.
        template<typename T>
        T &get(const std::string &name) const
        {
@@ -121,17 +122,12 @@ public:
                return *get_item(items, name).value<RefPtr<NCT> >();
        }
 
-       /**
-       Gets an object of a specific type from the collection.  If the name is not
-       found in the collection and there is a creator for the item type, it is
-       invoked.
-       */
+       /** Gets a typed object from the collection.  If the name is not found in
+       and a creator for the item type is defined, it is invoked. */
        template<typename T>
        T &get(const std::string &);
 
-       /**
-       Returns a list of the names of objects of a specific type in the collection.
-       */
+       /// Returns a list of the names of objects of one type in the collection.
        template<typename T>
        std::list<std::string> get_names() const
        {
@@ -142,9 +138,7 @@ public:
                return result;
        }
 
-       /**
-       Returns a list of objects of a specific type in the collection.
-       */
+       /// Returns a list of objects of one type in the collection.
        template<typename T>
        std::list<T *> get_list() const
        {
@@ -157,15 +151,11 @@ public:
                return result;
        }
 
-       /**
-       Checks whether a name exists in the collection.  Does not care about the
-       type of the object.
-       */
+       /** Checks whether a name exists in the collection.  Does not care about the
+       type of the object. */
        bool contains(const std::string &n) const;
 
-       /**
-       Returns the name of an item in the collection.
-       */
+       /// Returns the name of an item in the collection.
        template<typename T>
        const std::string &get_name(T *d) const
        {
@@ -181,6 +171,8 @@ public:
        }
 
 protected:
+       /** Adds a type to the collection.  The returned descriptor object reference
+       can be used to define how objects of that type can be loaded. */
        template<typename T>
        CollectionItemType<T> &add_type();
 };
@@ -237,6 +229,10 @@ public:
 };
 
 
+/**
+Describes a type of item that can be loaded by a Collection.  These are created
+by Collection::add_type.
+*/
 template<typename T>
 class CollectionItemType: public CollectionItemTypeBase
 {
@@ -304,12 +300,21 @@ public:
                delete store;
        }
 
+       /** Sets a datafile keyword for this item type.  The Collection's loader
+       will accept a statement with this keyword and a single string argument - the
+       item's name. */
        CollectionItemType &keyword(const std::string &k)
        {
                kwd = k;
                return *this;
        }
 
+       /** Attaches a creator function to this item type.  If an item is not found
+       in the Collection, the creator function for its type is called to create it.
+       The function must be a member of the Collection subclass containing the
+       type.  It must return the created object, or null if it could not be
+       created.  It's also permissible to load the item via other means and then
+       return null. */
        template<typename C>
        CollectionItemType &creator(T *(C::*func)(const std::string &))
        {
@@ -318,6 +323,8 @@ public:
                return *this;
        }
 
+       /** Specifies the storage type for items of this type.  It must be a base
+       class of the actual type.  */
        template<typename S>
        CollectionItemType &store_as()
        {