GdaSet

GdaSet — Container for several values

Synopsis

                    GdaSet;
GdaSet *            gda_set_new                         (GSList *holders);
GdaSet *            gda_set_new_read_only               (GSList *holders);
GdaSet *            gda_set_copy                        (GdaSet *set);
GdaSet *            gda_set_new_inline                  (gint nb,
                                                         ...);
GdaSet *            gda_set_new_from_spec_string        (const gchar *xml_spec,
                                                         GError **error);
GdaSet *            gda_set_new_from_spec_node          (xmlNodePtr xml_spec,
                                                         GError **error);
gboolean            gda_set_is_valid                    (GdaSet *set,
                                                         GError **error);
const GValue *      gda_set_get_holder_value            (GdaSet *set,
                                                         const gchar *holder_id);
gboolean            gda_set_set_holder_value            (GdaSet *set,
                                                         GError **error,
                                                         const gchar *holder_id,
                                                         ...);

GdaHolder *         gda_set_get_holder                  (GdaSet *set,
                                                         const gchar *holder_id);
GdaHolder *         gda_set_get_nth_holder              (GdaSet *set,
                                                         gint pos);
gboolean            gda_set_add_holder                  (GdaSet *set,
                                                         GdaHolder *holder);
void                gda_set_remove_holder               (GdaSet *set,
                                                         GdaHolder *holder);
void                gda_set_merge_with_set              (GdaSet *set,
                                                         GdaSet *set_to_merge);
void                gda_set_replace_source_model        (GdaSet *set,
                                                         GdaSetSource *source,
                                                         GdaDataModel *model);

                    GdaSetNode;
GdaSetNode *        gda_set_get_node                    (GdaSet *set,
                                                         GdaHolder *holder);
                    GdaSetSource;
GdaSetSource *      gda_set_get_source_for_model        (GdaSet *set,
                                                         GdaDataModel *model);
GdaSetSource *      gda_set_get_source                  (GdaSet *set,
                                                         GdaHolder *holder);
                    GdaSetGroup;
GdaSetGroup *       gda_set_get_group                   (GdaSet *set,
                                                         GdaHolder *holder);

Object Hierarchy

  GObject
   +----GdaSet
         +----GdaDataModelIter

Properties

  "description"              gchar*                : Read / Write
  "holders"                  gpointer              : Write / Construct Only
  "id"                       gchar*                : Read / Write
  "name"                     gchar*                : Read / Write
  "validate-changes"         gboolean              : Read / Write

Signals

  "holder-attr-changed"                            : Run First
  "holder-changed"                                 : Run First
  "holder-type-set"                                : Run First
  "public-data-changed"                            : Run First
  "source-model-changed"                           : Run First
  "validate-holder-change"                         : Run Last
  "validate-set"                                   : Run Last

Description

The GdaSet object is a container for several values (as GdaHolder objects). The list of GdaHolder objects is publicly accessible (and should not be modified), using the "holders" attribute. Each GdaSet object also maintains some publicly accessible information about the GdaHolder objects, through the GdaSetNode, GdaSetSource and GdaSetGroup structures (see gda_set_get_node(), gda_set_get_source() and gda_set_get_group()).

It is possible to control the values a GdaHolder can have in the GdaSet by connecting to the "before-holder-change" signal.

Details

GdaSet

typedef struct {
	GSList         *holders;   /* list of GdaHolder objects */
	GSList         *nodes_list;   /* list of GdaSetNode */
        GSList         *sources_list; /* list of GdaSetSource */
	GSList         *groups_list;  /* list of GdaSetGroup */
} GdaSet;

GSList *holders;

list of GdaHolder objects. [element-type Gda.Holder]

GSList *nodes_list;

list of GdaSetNode. [element-type Gda.SetNode]

GSList *sources_list;

list of GdaSetSource. [element-type Gda.SetSource]

GSList *groups_list;

list of GdaSetGroup. [element-type Gda.SetGroup]

gda_set_new ()

GdaSet *            gda_set_new                         (GSList *holders);

Creates a new GdaSet object, and populates it with the list given as argument. The list can then be freed as it is copied. All the value holders in holders are referenced counted and modified, so they should not be used anymore afterwards.

holders :

a list of GdaHolder objects. [element-type Gda.Holder][transfer none]

Returns :

a new GdaSet object

gda_set_new_read_only ()

GdaSet *            gda_set_new_read_only               (GSList *holders);

Creates a new GdaSet like gda_set_new(), but does not allow modifications to any of the GdaHolder object in holders. This function is used for Libgda's database providers' implementation.

holders :

a list of GdaHolder objects. [element-type Gda.Holder][transfer none]

Returns :

a new GdaSet object

Since 4.2


gda_set_copy ()

GdaSet *            gda_set_copy                        (GdaSet *set);

Creates a new GdaSet object, copy of set

set :

a GdaSet object

Returns :

a new GdaSet object. [transfer full]

gda_set_new_inline ()

GdaSet *            gda_set_new_inline                  (gint nb,
                                                         ...);

Creates a new GdaSet containing holders defined by each triplet in ... For each triplet (id, Glib type and value), the value must be of the correct type (gchar * if type is G_STRING, ...)

Note that this function is a utility function and that only a limited set of types are supported. Trying to use an unsupported type will result in a warning, and the returned value holder holding a safe default value.

nb :

the number of value holders which will be contained in the new GdaSet

... :

a serie of a (const gchar*) id, (GType) type, and value

Returns :

a new GdaSet object. [transfer full]

gda_set_new_from_spec_string ()

GdaSet *            gda_set_new_from_spec_string        (const gchar *xml_spec,
                                                         GError **error);

Creates a new GdaSet object from the xml_spec specifications

xml_spec :

a string

error :

a place to store the error, or NULL. [allow-none]

Returns :

a new object, or NULL if an error occurred. [transfer full]

gda_set_new_from_spec_node ()

GdaSet *            gda_set_new_from_spec_node          (xmlNodePtr xml_spec,
                                                         GError **error);

Creates a new GdaSet object from the xml_spec specifications

xml_spec :

a xmlNodePtr for a <holders> tag

error :

a place to store the error, or NULL. [allow-none]

Returns :

a new object, or NULL if an error occurred. [transfer full]

gda_set_is_valid ()

gboolean            gda_set_is_valid                    (GdaSet *set,
                                                         GError **error);

This method tells if all set's GdaHolder objects are valid, and if they represent a valid combination of values, as defined by rules external to Libgda: the "validate-set" signal is emitted and if none of the signal handlers return an error, then the returned value is TRUE, otherwise the return value is FALSE as soon as a signal handler returns an error.

set :

a GdaSet object

error :

a place to store validation errors, or NULL. [allow-none]

Returns :

TRUE if the set is valid

gda_set_get_holder_value ()

const GValue *      gda_set_get_holder_value            (GdaSet *set,
                                                         const gchar *holder_id);

Get the value of the GdaHolder which ID is holder_id

set :

a GdaSet object

holder_id :

the ID of the holder to set the value

Returns :

the requested GValue, or NULL (see gda_holder_get_value()). [transfer none]

gda_set_set_holder_value ()

gboolean            gda_set_set_holder_value            (GdaSet *set,
                                                         GError **error,
                                                         const gchar *holder_id,
                                                         ...);

Set the value of the GdaHolder which ID is holder_id to a specified value

set :

a GdaSet object

error :

a place to store errors, or NULL. [allow-none]

holder_id :

the ID of the holder to set the value

... :

value, of the correct type, depending on the requested holder's type (not NULL)

Returns :

TRUE if no error occurred and the value was set correctly

gda_set_get_holder ()

GdaHolder *         gda_set_get_holder                  (GdaSet *set,
                                                         const gchar *holder_id);

Finds a GdaHolder using its ID

set :

a GdaSet object

holder_id :

the ID of the requested value holder

Returns :

the requested GdaHolder or NULL. [transfer none]

gda_set_get_nth_holder ()

GdaHolder *         gda_set_get_nth_holder              (GdaSet *set,
                                                         gint pos);

Finds a GdaHolder using its position

set :

a GdaSet object

pos :

the position of the requested GdaHolder, starting at 0

Returns :

the requested GdaHolder or NULL. [transfer none]

Since 4.2


gda_set_add_holder ()

gboolean            gda_set_add_holder                  (GdaSet *set,
                                                         GdaHolder *holder);

Adds holder to the list of holders managed within set.

NOTE: if set already has a GdaHolder with the same ID as holder, then holder will not be added to the set (even if holder's type or value is not the same as the one already in set).

set :

a GdaSet object

holder :

a GdaHolder object

Returns :

TRUE if holder has been added to set (and FALSE if it has not been added because there is another GdaHolder with the same ID)

gda_set_remove_holder ()

void                gda_set_remove_holder               (GdaSet *set,
                                                         GdaHolder *holder);

Removes a GdaHolder from the list of holders managed by set

set :

a GdaSet object

holder :

the GdaHolder to remove from set

gda_set_merge_with_set ()

void                gda_set_merge_with_set              (GdaSet *set,
                                                         GdaSet *set_to_merge);

Add to set all the holders of set_to_merge. Note1: only the GdaHolder of set_to_merge for which no holder in set has the same ID are merged Note2: all the GdaHolder merged in set are still used by set_to_merge.

set :

a GdaSet object

set_to_merge :

a GdaSet object

gda_set_replace_source_model ()

void                gda_set_replace_source_model        (GdaSet *set,
                                                         GdaSetSource *source,
                                                         GdaDataModel *model);

Replaces source->data_model with model, which must have the same characteristics as source->data_model (same column types)

Also for each GdaHolder for which source->data_model is a source model, this method calls gda_holder_set_source_model() with model to replace the source by the new model

set :

a GdaSet object

source :

a pointer to a GdaSetSource in set

model :

a GdaDataModel

Since 4.2


GdaSetNode

typedef struct {
	GdaHolder    *holder;        /* Can't be NULL */
	GdaDataModel *source_model;  /* may be NULL */
	gint          source_column; /* unused if @source_model is NULL */
} GdaSetNode;

For each GdaHolder object in the GdaSet object, there is a GdaSetNode structure which sums up all the information for each GdaHolder. Contains public fields, which must not be modified.

GdaHolder *holder;

a GdaHolder in the GdaSet

GdaDataModel *source_model;

if gda_holder_set_source_model() has been used with holder, the GdaDataModel used, or NULL

gint source_column;

if gda_holder_set_source_model() has been used with holder, the column used, or 0

gda_set_get_node ()

GdaSetNode *        gda_set_get_node                    (GdaSet *set,
                                                         GdaHolder *holder);

Finds a GdaSetNode holding information for holder, don't modify the returned structure

set :

a GdaSet object

holder :

a GdaHolder object

Returns :

the requested GdaSetNode or NULL. [transfer none]

GdaSetSource

typedef struct {
	GdaDataModel   *data_model;   /* Can't be NULL */
	GSList         *nodes;        /* list of #GdaSetNode for which source_model == @data_model */
} GdaSetSource;

There is a GdaSetSource structure for each GdaDataModel which restricts at least one GdaHolder in the GdaSet object.

GdaDataModel *data_model;

Can't be NULL

GSList *nodes;

list of GdaSetNode for which source_model == data_model. [element-type Gda.SetNode]

gda_set_get_source_for_model ()

GdaSetSource *      gda_set_get_source_for_model        (GdaSet *set,
                                                         GdaDataModel *model);

Finds the GdaSetSource structure used in set for which model is a the data model (the returned structure should not be modified).

set :

a GdaSet object

model :

a GdaDataModel object

Returns :

the requested GdaSetSource pointer or NULL. [transfer none]

gda_set_get_source ()

GdaSetSource *      gda_set_get_source                  (GdaSet *set,
                                                         GdaHolder *holder);

Finds a GdaSetSource which contains the GdaDataModel restricting the possible values of holder, don't modify the returned structure.

set :

a GdaSet object

holder :

a GdaHolder object

Returns :

the requested GdaSetSource or NULL. [transfer none]

GdaSetGroup

typedef struct {
	GSList       *nodes;       /* list of GdaSetNode, at least one entry */
	GdaSetSource *nodes_source; /* if NULL, then @nodes contains exactly one entry */
} GdaSetGroup;

There is one GdaSetGroup structure for each _independent_ GdaHolder (those which have the same restricting data model all appear in the same GdaSetGroup structure).

GSList *nodes;

list of GdaSetNode, at least one entry. [element-type Gda.SetNode]

GdaSetSource *nodes_source;

if NULL, then nodes contains exactly one entry. [allow-none]

gda_set_get_group ()

GdaSetGroup *       gda_set_get_group                   (GdaSet *set,
                                                         GdaHolder *holder);

Finds a GdaSetGroup which lists a GdaSetNode containing holder, don't modify the returned structure.

set :

a GdaSet object

holder :

a GdaHolder object

Returns :

the requested GdaSetGroup or NULL. [transfer none]

Property Details

The "description" property

  "description"              gchar*                : Read / Write

Description.

Default value: NULL


The "holders" property

  "holders"                  gpointer              : Write / Construct Only

GdaHolder objects the set should contain.


The "id" property

  "id"                       gchar*                : Read / Write

Id.

Default value: NULL


The "name" property

  "name"                     gchar*                : Read / Write

Name.

Default value: NULL


The "validate-changes" property

  "validate-changes"         gboolean              : Read / Write

Defines if the "validate-set" signal gets emitted when any holder in the data set changes. This property also affects the GdaHolder:validate-changes property.

Default value: TRUE

Since 5.2.0

Signal Details

The "holder-attr-changed" signal

void                user_function                      (GdaSet    *set,
                                                        GdaHolder *holder,
                                                        gchar     *attr_name,
                                                        GValue    *attr_value,
                                                        gpointer   user_data)       : Run First

Gets emitted when an attribute for any of the GdaHolder objects managed by set has changed

set :

the GdaSet

holder :

the GdaHolder for which an attribute changed

attr_name :

attribute's name

attr_value :

attribute's value

user_data :

user data set when the signal handler was connected.

The "holder-changed" signal

void                user_function                      (GdaSet    *gdaset,
                                                        GdaHolder *arg1,
                                                        gpointer   user_data)      : Run First

gdaset :

the object which received the signal.

user_data :

user data set when the signal handler was connected.

The "holder-type-set" signal

void                user_function                      (GdaSet    *set,
                                                        GdaHolder *holder,
                                                        gpointer   user_data)      : Run First

Gets emitted when holder in set has its type finally set, in case it was GDA_TYPE_NULL

set :

the GdaSet

holder :

the GdaHolder for which the GType has been set

user_data :

user data set when the signal handler was connected.

Since 4.2


The "public-data-changed" signal

void                user_function                      (GdaSet  *set,
                                                        gpointer user_data)      : Run First

Gets emitted when set's public data (GdaSetNode, GdaSetGroup or GdaSetSource values) have changed

set :

the GdaSet

user_data :

user data set when the signal handler was connected.

The "source-model-changed" signal

void                user_function                      (GdaSet  *set,
                                                        gpointer source,
                                                        gpointer user_data)      : Run First

Gets emitted when the data model in source has changed

set :

the GdaSet

source :

the GdaSetSource for which the data_model attribute has changed

user_data :

user data set when the signal handler was connected.

Since 4.2


The "validate-holder-change" signal

GdaError*           user_function                      (GdaSet    *set,
                                                        GdaHolder *holder,
                                                        GValue    *new_value,
                                                        gpointer   user_data)      : Run Last

Gets emitted when a GdaHolder's in set is going to change its value. One can connect to this signal to control which values holder can have (for example to implement some business rules)

set :

the GdaSet

holder :

the GdaHolder which is going to change

new_value :

the proposed new value for holder

user_data :

user data set when the signal handler was connected.

Returns :

NULL if holder is allowed to change its value to new_value, or a GError otherwise.

The "validate-set" signal

GdaError*           user_function                      (GdaSet  *set,
                                                        gpointer user_data)      : Run Last

Gets emitted when gda_set_is_valid() is called, use this signal to control which combination of values set's holder can have (for example to implement some business rules)

set :

the GdaSet

user_data :

user data set when the signal handler was connected.

Returns :

NULL if set's contents has been validated, or a GError otherwise.