TransformFeatureSource (Geotools modules 21.0 API)

Object
- 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:
- hide, rename fields - compute new fields
- build geom from x,y (we need to add a new Point filter function and have a special treatment of it in simplifying filter visitor so that it turns bbox filters against it into a filter on x,y)
- on the fly simplification for WFS (just use environment variables) and in general dynamic processing based on params without stored queries
Author:

Andrea Aime - GeoSolutions

Field Summary

Fields
Modifier and Type	Field and Description
`protected static FilterFactory2`	`FF`
`protected static Logger`	`LOGGER`
`protected SimpleFeatureSource`	`source`
`protected Transformer`	`transformer`

Constructor Summary

Constructors
Constructor and Description
`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

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`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

Class TransformFeatureSource

Field Summary

Constructor Summary

Method Summary

Methods inherited from class Object

Field Detail

LOGGER

FF

transformer

source

Constructor Detail

TransformFeatureSource

Method Detail

getName

getInfo

getDataStore

getQueryCapabilities

addFeatureListener

removeFeatureListener

getSchema

getBounds

getBounds

getCount

getSupportedHints

getFeatures

getFeatures

getFeatures