org.geotools.data.transform
Class TransformFeatureSource

Object
  extended by TransformFeatureSource
All Implemented Interfaces:
FeatureSource<SimpleFeatureType,SimpleFeature>, SimpleFeatureSource
Direct Known Subclasses:
TransformFeatureStore

public class TransformFeatureSource
extends Object
implements SimpleFeatureSource

A feature source that can transform a source feature source using a set of expressions Usages:

Author:
Andrea Aime - GeoSolutions

Field Summary
protected static FilterFactory2 FF
           
protected static Logger LOGGER
           
protected  SimpleFeatureSource source
           
protected  Transformer transformer
           
 
Constructor Summary
TransformFeatureSource(SimpleFeatureSource source, Name name, List<Definition> definitions)
          Creates a transformed feature source from the original source, giving it a certain name and a set of computed properties
 
Method Summary
 void addFeatureListener(FeatureListener listener)
          Registers a listening object that will be notified of changes to this FeatureSource.
 ReferencedEnvelope getBounds()
          Get the spatial bounds of the feature data.
 ReferencedEnvelope getBounds(Query query)
          Get the spatial bounds of the features that would be returned by the given Query.
 int getCount(Query query)
          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.
 DataAccess<SimpleFeatureType,SimpleFeature> getDataStore()
          Returns the data source, as a DataAccess object, providing this FeatureSource.
 SimpleFeatureCollection getFeatures()
          Retrieves all features in the form of a FeatureCollection.
 SimpleFeatureCollection getFeatures(Filter filter)
          Retrieves features, in the form of a FeatureCollection, based on an OGC Filter.
 SimpleFeatureCollection getFeatures(Query query)
          Retrieves features, in the form of a FeatureCollection, based on a Query.
 ResourceInfo getInfo()
          Returns information describing this FeatureSource which may include title, description and spatial parameters.
 Name getName()
          Returns the name of the features (strictly, the name of the AttributeDescriptor for the features) accessible through this FeatureSource.
 QueryCapabilities getQueryCapabilities()
          Enquire what what query capabilities this FeatureSource natively supports.
 SimpleFeatureType getSchema()
          Retrieves the schema (feature type) that will apply to features retrieved from this FeatureSource.
 Set<RenderingHints.Key> getSupportedHints()
          Returns the set of hints that this FeatureSource supports via Query requests.
 void removeFeatureListener(FeatureListener listener)
          Removes an object from this FeatureSource's listeners.
 
Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

LOGGER

protected static final Logger LOGGER

FF

protected static final FilterFactory2 FF

transformer

protected Transformer transformer

source

protected SimpleFeatureSource source
Constructor Detail

TransformFeatureSource

public TransformFeatureSource(SimpleFeatureSource source,
                              Name name,
                              List<Definition> definitions)
                       throws IOException
Creates a transformed feature source from the original source, giving it a certain name and a set of computed properties

Parameters:
source -
name -
definitions -
Throws:
IOException
Method Detail

getName

public Name getName()
Description copied from interface: FeatureSource
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).

Specified by:
getName in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Returns:
the name of the features accessible through this FeatureSource

getInfo

public ResourceInfo getInfo()
Description copied from interface: FeatureSource
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 FeatureSource.getName().

Specified by:
getInfo in interface FeatureSource<SimpleFeatureType,SimpleFeature>

getDataStore

public DataAccess<SimpleFeatureType,SimpleFeature> getDataStore()
Description copied from interface: FeatureSource
Returns the data source, as a DataAccess object, providing this FeatureSource.

Specified by:
getDataStore in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Returns:
the data source providing this FeatureSource

getQueryCapabilities

public QueryCapabilities getQueryCapabilities()
Description copied from interface: FeatureSource
Enquire what what query capabilities this FeatureSource natively supports. For example, whether queries can return sorted results.

Specified by:
getQueryCapabilities in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Returns:
the native query capabilities of this FeatureSource

addFeatureListener

public void addFeatureListener(FeatureListener listener)
Description copied from interface: FeatureSource
Registers a listening object that will be notified of changes to this FeatureSource.

Specified by:
addFeatureListener in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Parameters:
listener - the new listener

removeFeatureListener

public void removeFeatureListener(FeatureListener listener)
Description copied from interface: FeatureSource
Removes an object from this FeatureSource's listeners.

Specified by:
removeFeatureListener in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Parameters:
listener - the listener to remove

getSchema

public SimpleFeatureType getSchema()
Description copied from interface: FeatureSource
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.

Specified by:
getSchema in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Returns:
the schema that will apply to features retrieved from this FeatureSource

getBounds

public ReferencedEnvelope getBounds()
                             throws IOException
Description copied from interface: FeatureSource
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.

Specified by:
getBounds in interface FeatureSource<SimpleFeatureType,SimpleFeature>
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

public ReferencedEnvelope getBounds(Query query)
                             throws IOException
Description copied from interface: FeatureSource
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.

Specified by:
getBounds in interface FeatureSource<SimpleFeatureType,SimpleFeature>
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

public int getCount(Query query)
             throws IOException
Description copied from interface: FeatureSource
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();
 }

Specified by:
getCount in interface FeatureSource<SimpleFeatureType,SimpleFeature>
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

getSupportedHints

public Set<RenderingHints.Key> getSupportedHints()
Description copied from interface: FeatureSource
Returns the set of hints that this FeatureSource supports via Query requests.

Note: the existence of a specific hint does not guarantee that it will always be honored by the implementing class.

Specified by:
getSupportedHints in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Returns:
a set of RenderingHints#Key objects; may be empty but never null
See Also:
Hints.FEATURE_DETACHED, Hints.JTS_GEOMETRY_FACTORY, Hints.JTS_COORDINATE_SEQUENCE_FACTORY, Hints.JTS_PRECISION_MODEL, Hints.JTS_SRID, Hints.GEOMETRY_DISTANCE, Hints.FEATURE_2D

getFeatures

public SimpleFeatureCollection getFeatures()
                                    throws IOException
Description copied from interface: FeatureSource
Retrieves all features in the form of a FeatureCollection.

The following statements are equivalent:


     featureSource.getFeatures();
     featureSource.getFeatures(Filter.INCLUDE);
     featureSource.getFeatures(Query.ALL);
 

Specified by:
getFeatures in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Specified by:
getFeatures in interface SimpleFeatureSource
Returns:
features retrieved by the Query
Throws:
IOException - if the underlying data source cannot be accessed.

getFeatures

public SimpleFeatureCollection getFeatures(Filter filter)
                                    throws IOException
Description copied from interface: FeatureSource
Retrieves features, in the form of a FeatureCollection, based on an OGC Filter.

Specified by:
getFeatures in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Specified by:
getFeatures in interface SimpleFeatureSource
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

public SimpleFeatureCollection getFeatures(Query query)
                                    throws IOException
Description copied from interface: FeatureSource
Retrieves features, in the form of a FeatureCollection, based on a Query.

Specified by:
getFeatures in interface FeatureSource<SimpleFeatureType,SimpleFeature>
Specified by:
getFeatures in interface SimpleFeatureSource
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


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