Package org.geotools.api.data

Interface FeatureSource<T extends FeatureType,​F extends Feature>

    • Method Detail

      • getName

        Name getName()
        Returns the name of the features (strictly, the name of the AttributeDescriptor for the features) accessible through this FeatureSource.

        The value returned by this method can be different to that returned by featureSource.getSchema().getType().getName(). This is because there is a distinction between the name applied to features and the name of a feature type. When working with SimpleFeature and SimpleFeatureType, for example with a shapefile data source, it is common practice for feature and feature type names to be the same. However, this is not the case more generally. For instance, a database can contain two tables with the same structure. The feature name will refer to the table while the feature type name refers to the schema (table structure).

        Returns:
        the name of the features accessible through this FeatureSource
        Since:
        2.5

      • getInfo

        ResourceInfo getInfo()
        Returns information describing this FeatureSource which may include title, description and spatial parameters. Note that in the returned ResourceInfo object, the distinction between feature name and schema (feature type) name applies as discussed for getName().

      • getDataStore

        DataAccess<T,​F> getDataStore()
        Returns the data source, as a DataAccess object, providing this FeatureSource.
        Returns:
        the data source providing this FeatureSource

      • getQueryCapabilities

        QueryCapabilities getQueryCapabilities()
        Enquire what what query capabilities this FeatureSource natively supports. For example, whether queries can return sorted results.
        Returns:
        the native query capabilities of this FeatureSource
        Since:
        2.5

      • addFeatureListener

        void addFeatureListener​(FeatureListener listener)
        Registers a listening object that will be notified of changes to this FeatureSource.
        Parameters:
        listener - the new listener

      • removeFeatureListener

        void removeFeatureListener​(FeatureListener listener)
        Removes an object from this FeatureSource's listeners.
        Parameters:
        listener - the listener to remove

      • getFeatures

        FeatureCollection<T,​F> getFeatures​(Filter filter)
                                  throws IOException
        Retrieves features, in the form of a FeatureCollection, based on an OGC Filter.
        Parameters:
        filter - the filter to select features; must not be null (use Filter.INCLUDE instead)
        Returns:
        features retrieved by the Filter
        Throws:
        IOException - if the underlying data source cannot be accessed.
        See Also:
        Filter

      • getFeatures

        FeatureCollection<T,​F> getFeatures​(Query query)
                                  throws IOException
        Retrieves features, in the form of a FeatureCollection, based on a Query.
        Parameters:
        query - DataAccess query for requested information, such as typeName, maxFeatures and filter.
        Returns:
        features retrieved by the Query
        Throws:
        IOException - if the underlying data source cannot be accessed.
        See Also:
        Query

      • getFeatures

        FeatureCollection<T,​F> getFeatures()
                                  throws IOException
        Retrieves all features in the form of a FeatureCollection.

        The following statements are equivalent: 

        
     featureSource.getFeatures();
     featureSource.getFeatures(Filter.INCLUDE);
     featureSource.getFeatures(Query.ALL);
        Returns:
        features retrieved by the Query
        Throws:
        IOException - if the underlying data source cannot be accessed.

      • getSchema

        T getSchema()
        Retrieves the schema (feature type) that will apply to features retrieved from this FeatureSource.

        For a homogeneous data source such as a shapefile or a database table, this schema be that of all features. For a heterogeneous data source, e.g. a GML document, the schema returned is the lowest common denominator across all features.

        Returns:
        the schema that will apply to features retrieved from this FeatureSource

      • getBounds

        ReferencedEnvelope getBounds()
                      throws IOException
        Get the spatial bounds of the feature data. This is equivalent to calling getBounds(Query.ALL).

        It is possible that this method will return null if the calculation of bounds is judged to be too costly by the implementing class. In this case, you might call getFeatures().getBounds() instead.

        Returns:
        The bounding envelope of the feature data; or null if the bounds are unknown or too costly to calculate.
        Throws:
        IOException - on any errors calculating the bounds

      • getBounds

        ReferencedEnvelope getBounds​(Query query)
                      throws IOException
        Get the spatial bounds of the features that would be returned by the given Query.

        It is possible that this method will return null if the calculation of bounds is judged to be too costly by the implementing class. In this case, you might call getFeatures(query).getBounds() instead.

        Parameters:
        query - the query to select features
        Returns:
        The bounding envelope of the feature data; or null if the bounds are unknown or too costly to calculate.
        Throws:
        IOException - on any errors calculating the bounds

      • getCount

        int getCount​(Query query)
      throws IOException
        Gets the number of the features that would be returned by the given Query, taking into account any settings for max features and start index set on the Query.

        It is possible that this method will return -1 if the calculation of number of features is judged to be too costly by the implementing class. In this case, you might call getFeatures(query).size() instead.

        Example use:

         int count = featureSource.getCount();
 if( count == -1 ){
    count = featureSource.getFeatures( "typeName", count ).size();
 }
        Parameters:
        query - the query to select features
        Returns:
        the numer of features that would be returned by the Query; or -1 if this cannot be calculated.
        Throws:
        IOException - if there are errors getting the count