Package org.geotools.data.store

Class DataFeatureCollection

Object

DataFeatureCollection

All Implemented Interfaces:

SimpleFeatureCollection, FeatureCollection<SimpleFeatureType,SimpleFeature>

Direct Known Subclasses:

CompositeFeatureCollection, DefaultFeatureResults, EmptyFeatureCollection, IndexedFeatureResults

public abstract class DataFeatureCollection
extends Object
implements SimpleFeatureCollection

A starting point for implementing FeatureCollection's backed onto a FeatureReader.

This implementation requires you to implement the following:

• getSchema() - this should match reader.getSchema()
• reader()
  features() - override one of these two method to access content
• getBounds()
• getCount()
• collection()

  This class will implement the 'extra' methods required by FeatureCollection for you (in simple terms based on the FeatureResults API). Anything that is often customised is available to you as a constructor parameters.

  Enjoy.

Since:

2.1.RC0

Author:

jgarnett

Field Summary

Fields

Modifier and Type	Field	Description
protected String	id	id used when serialized to gml
protected List<CollectionListener>	listeners	listeners
protected SimpleFeatureType	schema

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DataFeatureCollection()	Collection based on a generic collection
protected	DataFeatureCollection(String id)	Collection based on a generic collection
protected	DataFeatureCollection(String id, SimpleFeatureType memberType)	Subclass must think about what consitructors it needs.

Method Summary

Modifier and Type	Method	Description
void	accepts(FeatureVisitor visitor, ProgressListener progress)	Visit the contents of a feature collection.
boolean	add(SimpleFeature arg0)
boolean	addAll(Collection collection)	Optimized implementation of addAll that recognizes the use of collections obtained with subCollection( filter ).
boolean	addAll(FeatureCollection resource)
void	addListener(CollectionListener listener)
void	clear()
void	close(Iterator<SimpleFeature> close)
void	close(FeatureIterator<SimpleFeature> iterator)
protected void	closeIterator(Iterator<SimpleFeature> close)
boolean	contains(Object o)
boolean	containsAll(Collection<?> collection)
SimpleFeatureIterator	features()	SimpleFeatureIterator is entirely based on iterator().
protected void	fireChange(Collection coll, int type)
protected void	fireChange(SimpleFeature[] features, int type)	To let listeners know that something has changed.
protected void	fireChange(SimpleFeature feature, int type)
abstract ReferencedEnvelope	getBounds()	Get the total bounds of this collection which is calculated by doing a union of the bounds of each feature inside of it
abstract int	getCount()
String	getID()	ID used when serializing to GML
SimpleFeatureType	getSchema()	The schema for the child feature members of this collection.
boolean	isEmpty()	Default implementation based on creating an reader, testing hasNext, and closing.
Iterator<SimpleFeature>	iterator()	Iterator may (or may) not support modification.
protected Iterator<SimpleFeature>	openIterator()	Returns a FeatureWriterIterator, or FeatureReaderIterator over content.
void	purge()
FeatureReader<SimpleFeatureType,SimpleFeature>	reader()
boolean	remove(Object arg0)
boolean	removeAll(Collection arg0)
void	removeListener(CollectionListener listener)
boolean	retainAll(Collection arg0)
int	size()	Default implementation based on getCount() - this may be expensive
SimpleFeatureCollection	sort(SortBy order)	Construct a sorted view of this content.
SimpleFeatureCollection	subCollection(Filter filter)	Will return an optimized subCollection based on access to the origional FeatureSource.
Object[]	toArray()
<T> T[]	toArray(T[] array)
protected FeatureWriter<SimpleFeatureType,SimpleFeature>	writer()	Subclass may provide an implementation of this method to indicate that read/write support is provided.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

listeners

protected List<CollectionListener> listeners

listeners

id

protected String id

id used when serialized to gml

schema

protected SimpleFeatureType schema

Constructor Detail

DataFeatureCollection

protected DataFeatureCollection()

Collection based on a generic collection

DataFeatureCollection

protected DataFeatureCollection(String id)

Collection based on a generic collection

DataFeatureCollection

protected DataFeatureCollection(String id,
                                SimpleFeatureType memberType)

Subclass must think about what consitructors it needs.

Method Detail

fireChange

protected void fireChange(SimpleFeature[] features,
                          int type)

To let listeners know that something has changed.

fireChange

protected void fireChange(SimpleFeature feature,
                          int type)

fireChange

protected void fireChange(Collection coll,
                          int type)

reader

public FeatureReader<SimpleFeatureType,SimpleFeature> reader()
                                                            throws IOException

Throws:

IOException

getBounds

public abstract ReferencedEnvelope getBounds()

Description copied from interface: FeatureCollection

Get the total bounds of this collection which is calculated by doing a union of the bounds of each feature inside of it

Specified by:

getBounds in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Returns:

An Envelope containing the total bounds of this collection.

getCount

public abstract int getCount()
                      throws IOException

Throws:

IOException

writer

protected FeatureWriter<SimpleFeatureType,SimpleFeature> writer()
                                                               throws IOException

Subclass may provide an implementation of this method to indicate that read/write support is provided.

All operations that attempt to modify the "data" will use this method, allowing them to throw an "UnsupportedOperationException" in the same manner as Collections.unmodifiableCollection(Collection c), or just return null.

Returns:

the writer, or null if write support is not available

Throws:

UnsupportedOperationException - To indicate that write support is not avaiable

IOException

features

public SimpleFeatureIterator features()

SimpleFeatureIterator is entirely based on iterator().

So when we implement FeatureCollection.iterator() this will work out of the box.

Specified by:

features in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Specified by:

features in interface SimpleFeatureCollection

Returns:

A FeatureIterator.

iterator

public final Iterator<SimpleFeature> iterator()

Iterator may (or may) not support modification.

openIterator

protected Iterator<SimpleFeature> openIterator()
                                        throws IOException

Returns a FeatureWriterIterator, or FeatureReaderIterator over content.

If you have a way to tell that you are readonly please subclass with a less hardcore check - this implementations catches a UnsupportedOpperationsException from wrtier()!

Returns:

Iterator, should be closed closeIterator

Throws:

IOException

close

public final void close(Iterator<SimpleFeature> close)

closeIterator

protected void closeIterator(Iterator<SimpleFeature> close)
                      throws IOException

Throws:

IOException

close

public void close(FeatureIterator<SimpleFeature> iterator)

size

public int size()

Default implementation based on getCount() - this may be expensive

Specified by:

size in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

See Also:

Collection.size()

purge

public void purge()

isEmpty

public boolean isEmpty()

Default implementation based on creating an reader, testing hasNext, and closing.

For once the Collections API does not give us an escape route, we *have* to check the data.

Specified by:

isEmpty in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Returns:

true if this collection contains no features

contains

public boolean contains(Object o)

Specified by:

contains in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

See Also:

Collection.contains(Object)

toArray

public Object[] toArray()

Specified by:

toArray in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

See Also:

Collection.toArray()

toArray

public <T> T[] toArray(T[] array)

Specified by:

toArray in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

See Also:

Collection.toArray(Object[])

add

public boolean add(SimpleFeature arg0)

remove

public boolean remove(Object arg0)

containsAll

public boolean containsAll(Collection<?> collection)

Specified by:

containsAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

See Also:

Collection.containsAll(Collection)

addAll

public boolean addAll(Collection collection)

Optimized implementation of addAll that recognizes the use of collections obtained with subCollection( filter ).

This method is constructed by either:

• Filter OR
• Removing an extact match of Filter AND

addAll

public boolean addAll(FeatureCollection resource)

removeAll

public boolean removeAll(Collection arg0)

retainAll

public boolean retainAll(Collection arg0)

clear

public void clear()

accepts

public void accepts(FeatureVisitor visitor,
                    ProgressListener progress)
             throws IOException

Description copied from interface: FeatureCollection

Visit the contents of a feature collection.

The order of traversal is dependent on the FeatureCollection implementation; some collections are able to make efficient use of an internal index in order to quickly visit features located in the same region.

Specified by:

accepts in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Parameters:

visitor - Closure applied to each feature in turn.

progress - Used to report progress, may be used to interrupt the operation

Throws:

IOException

subCollection

public SimpleFeatureCollection subCollection(Filter filter)

Will return an optimized subCollection based on access to the origional FeatureSource.

The subCollection is constructed by using an AND Filter. For the converse of this opperation please see collection.addAll( Collection ), it has been optimized to be aware of these filter based SubCollections.

This method is intended in a manner similar to subList, example use: collection.subCollection( myFilter ).clear()

Specified by:

subCollection in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Specified by:

subCollection in interface SimpleFeatureCollection

Parameters:

filter - Filter used to determine sub collection.

Returns:

SimpleFeatureCollection identified as subset.

Since:

GeoTools 2.2, Filter 1.1

See Also:

FeatureList

sort

public SimpleFeatureCollection sort(SortBy order)

Construct a sorted view of this content.

Sorts may be combined togther in a stable fashion, in congruence with the Filter 1.1 specification. This method should also be able to handle GeoTools specific sorting through detecting order as a SortBy2 instance.

Specified by:

sort in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Specified by:

sort in interface SimpleFeatureCollection

Parameters:

order - Sort order

Returns:

FeatureList sorted according to provided order

Since:

GeoTools 2.2, Filter 1.1

getID

public String getID()

Description copied from interface: FeatureCollection

ID used when serializing to GML

Specified by:

getID in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

addListener

public final void addListener(CollectionListener listener)
                       throws NullPointerException

Throws:

NullPointerException

removeListener

public final void removeListener(CollectionListener listener)
                          throws NullPointerException

Throws:

NullPointerException

getSchema

public SimpleFeatureType getSchema()

Description copied from interface: FeatureCollection

The schema for the child feature members of this collection.

Represents the most general FeatureType in common to all the features in this collection.

• For a collection backed by a shapefiles (or database tables) the FeatureType returned by getSchema() will complete describe each and every child in the collection.
• For mixed content FeatureCollections you will need to check the FeatureType of each Feature as it is retrived from the collection
• The degenerate case returns the "_Feature" FeatureType, where the only thing known is that the contents are Features.

Specified by:

getSchema in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

Returns:

FeatureType describing the "common" schema to all child features of this collection