]> Iterator 3 REDLAND Library Iterator Iterate a sequence of objects across some other object. typedef librdf_iterator; void* (*librdf_iterator_map_handler) (librdf_iterator *iterator, void *map_context, void *item); void (*librdf_iterator_map_free_context_handler) (void *map_context); librdf_iterator* librdf_new_iterator (librdf_world *world, void *context, int (is_end_methodvoid*) (), int (next_methodvoid*) (), void* (get_methodvoid*, int) (), void (finished_methodvoid*) ()); void librdf_free_iterator (librdf_iterator *iterator); int librdf_iterator_end (librdf_iterator *iterator); int librdf_iterator_have_elements (librdf_iterator *iterator); int librdf_iterator_next (librdf_iterator *iterator); void* librdf_iterator_get_object (librdf_iterator *iterator); void* librdf_iterator_get_context (librdf_iterator *iterator); void* librdf_iterator_get_key (librdf_iterator *iterator); void* librdf_iterator_get_value (librdf_iterator *iterator); int librdf_iterator_add_map (librdf_iterator *iterator, librdf_iterator_map_handler map_function, librdf_iterator_map_free_context_handler free_context, void *map_context); librdf_iterator* librdf_new_empty_iterator (librdf_world *world); Provides a way to operate across a sequence of objects that are generated one-by-one on demand. The returned objects can be of any type but the main public methods are on the librdf_model classs and return sequence of librdf_node objects such as librdf_model_get_sources(). librdf_iteratortypedef struct librdf_iterator_s librdf_iterator; Redland iterator class. librdf_iterator_map_handlervoid* (*librdf_iterator_map_handler) (librdf_iterator *iterator, void *map_context, void *item); Map function for a librdf_iterator map operation. See librdf_iterator_add_map(). iterator : Iterator that this map is operating over. map_context : Map data context pointer. item : Pointer to the current item in the iteration. Returns : item in keep the iteration or NULL to remove it librdf_iterator_map_free_context_handlervoid (*librdf_iterator_map_free_context_handler) (void *map_context); Free handler function for a librdf_iterator map operation. See librdf_iterator_add_map(). map_context : Map data context pointer. librdf_new_iteratorlibrdf_iterator* librdf_new_iterator (librdf_world *world, void *context, int (is_end_methodvoid*) (), int (next_methodvoid*) (), void* (get_methodvoid*, int) (), void (finished_methodvoid*) ()); Constructor - create a new librdf_iterator object. The iterator object takes ownership of context and frees it with finished_method. The finished method is not called if librdf_new_iterator fails and returns NULL. world : redland world object context : context to pass to the iterator functions is_end_method : function to call to see if the iteration has ended next_method : function to get the next element get_method : function to get the next element finished_method : function to destroy the iterator context (or NULL if not needed) Returns : a new librdf_iterator object or NULL on failure librdf_free_iteratorvoid librdf_free_iterator (librdf_iterator *iterator); Destructor - destroy a librdf_iterator object. iterator : the librdf_iterator object librdf_iterator_endint librdf_iterator_end (librdf_iterator *iterator); Test if the iterator has finished. iterator : the librdf_iterator object Returns : non 0 if the iterator has finished librdf_iterator_have_elementsint librdf_iterator_have_elements (librdf_iterator *iterator); Test if the iterator has finished. DEPRECATED - use !librdf_iterator_end(iterator) iterator : the librdf_iterator object Returns : 0 if the iterator has finished librdf_iterator_nextint librdf_iterator_next (librdf_iterator *iterator); Move to the next iterator element. iterator : the librdf_iterator object Returns : non 0 if the iterator has finished librdf_iterator_get_objectvoid* librdf_iterator_get_object (librdf_iterator *iterator); Get the current object from the iterator. This method returns a SHARED pointer to the current iterator object which should be copied by the caller to preserve it if the iterator is moved on librdf_iterator_next or if it should last after the iterator is closed. iterator : the librdf_iterator object Returns : The next element or NULL if the iterator has finished. librdf_iterator_get_contextvoid* librdf_iterator_get_context (librdf_iterator *iterator); Get the context of the current object on the iterator. This method returns a SHARED pointer to the current context node object which should be copied by the caller to preserve it if the iterator is moved on librdf_iterator_next or if it should last after the iterator is closed. iterator : the librdf_iterator object Returns : The context (can be NULL) or NULL if the iterator has finished. librdf_iterator_get_keyvoid* librdf_iterator_get_key (librdf_iterator *iterator); Get the key of the current object on the iterator. iterator : the librdf_iterator object Returns : The context or NULL if the iterator has finished. librdf_iterator_get_valuevoid* librdf_iterator_get_value (librdf_iterator *iterator); Get the value of the current object on the iterator. iterator : the librdf_iterator object Returns : The context or NULL if the iterator has finished. librdf_iterator_add_mapint librdf_iterator_add_map (librdf_iterator *iterator, librdf_iterator_map_handler map_function, librdf_iterator_map_free_context_handler free_context, void *map_context); Add a librdf_iterator mapping function. Adds an iterator mapping function which operates over the iterator to select which elements are returned; it will be applied as soon as this method is called. Several mapping functions can be added and they are applied in the order given The mapping function should return non 0 to allow the element to be returned. iterator : the iterator map_function : the function to operate free_context : the function to use to free the context (or NULL) map_context : the context to pass to the map function Returns : Non 0 on failure librdf_new_empty_iteratorlibrdf_iterator* librdf_new_empty_iterator (librdf_world *world); Constructor - create a new librdf_iterator with no content. world : redland world object Returns : a new librdf_iterator object or NULL on failure