org.geotools.feature
Class DefaultFeatureCollection

Object
  extended by DefaultFeatureCollection
All Implemented Interfaces:
FeatureCollection<SimpleFeatureType,SimpleFeature>
Direct Known Subclasses:
GMLFeatureCollection

public class DefaultFeatureCollection
extends Object
implements FeatureCollection<SimpleFeatureType,SimpleFeature>

A basic implementation of FeatureCollection which use a TreeMap for its internal storage.

This should be considered a MemoryFeatureCollection.

Author:
Ian Schneider
Module:
modules/library/main (gt-main.jar)

Field Summary
protected  String id
          id used when serialized to gml
protected  List listeners
          listeners
protected static Logger LOGGER
           
protected  SimpleFeatureType schema
           
 
Constructor Summary
DefaultFeatureCollection(FeatureCollection<SimpleFeatureType,SimpleFeature> collection)
          This constructor should not be used by client code.
DefaultFeatureCollection(String id, SimpleFeatureType memberType)
          This constructor should not be used by client code.
 
Method Summary
 void accepts(FeatureVisitor visitor, ProgressListener progress)
          Visit the contents of a feature collection.
 void accepts(FeatureVisitor visitor, ProgressListener progress)
           
 boolean add(SimpleFeature o)
          Ensures that this collection contains the specified element (optional operation).
protected  boolean add(SimpleFeature feature, boolean fire)
           
 boolean addAll(Collection collection)
          Adds all of the elements in the specified collection to this collection (optional operation).
 boolean addAll(FeatureCollection collection)
           
 void addListener(CollectionListener listener)
          Adds a listener for collection events.
 void clear()
          Removes all of the elements from this collection (optional operation).
 void close(FeatureIterator<SimpleFeature> close)
          Clean up after any resources associated with this FeatureIterator in a manner similar to JDO collections.
 void close(Iterator close)
          Clean up after any resources associated with this itterator in a manner similar to JDO collections.
 FeatureCollection<SimpleFeatureType,SimpleFeature> collection()
           
 boolean contains(Object o)
          Returns true if this collection contains the specified element.
 boolean containsAll(Collection collection)
          Test for collection membership.
 FeatureIterator<SimpleFeature> features()
          Gets a FeatureIterator of this feature collection.
 Set fids()
          Optimization time ... grab the fid set so other can quickly test membership during removeAll/retainAll implementations.
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)
           
 ReferencedEnvelope getBounds()
          Gets the bounding box for the features in this feature collection.
 int getCount()
           
 String getID()
          ID used when serializing to GML
 SimpleFeatureType getSchema()
          The schema for the child features of this collection.
 boolean isEmpty()
          Returns true if this collection contains no elements.
 Iterator iterator()
          Returns an iterator over the elements in this collection.
 void purge()
          Close any outstanding resources released by this resources.
 FeatureReader<SimpleFeatureType,SimpleFeature> reader()
           
 boolean remove(Object o)
          Removes a single instance of the specified element from this collection, if it is present (optional operation).
 boolean removeAll(Collection collection)
          Removes all this collection's elements that are also contained in the specified collection (optional operation).
 void removeListener(CollectionListener listener)
          Removes a listener for collection events.
 boolean retainAll(Collection collection)
          Retains only the elements in this collection that are contained in the specified collection (optional operation).
 int size()
          Returns the number of elements in this collection.
 FeatureCollection<SimpleFeatureType,SimpleFeature> sort(SortBy order)
          Construct a sorted view of this content.
 FeatureCollection<SimpleFeatureType,SimpleFeature> sort(SortBy2 order)
          Allows for "Advanced" sort capabilities specific to the GeoTools platform!
 FeatureCollection<SimpleFeatureType,SimpleFeature> subCollection(Filter filter)
          Will return an optimized subCollection based on access to the origional MemoryFeatureCollection.
 Object[] toArray()
          Returns an array containing all of the elements in this collection.
 Object[] toArray(Object[] a)
          Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array.
 void validate()
           
 
Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

LOGGER

protected static Logger LOGGER

listeners

protected List listeners
listeners


id

protected String id
id used when serialized to gml


schema

protected SimpleFeatureType schema
Constructor Detail

DefaultFeatureCollection

public DefaultFeatureCollection(FeatureCollection<SimpleFeatureType,SimpleFeature> collection)
This constructor should not be used by client code.

Parameters:
collection - FeatureCollection to copy into memory

DefaultFeatureCollection

public DefaultFeatureCollection(String id,
                                SimpleFeatureType memberType)
This constructor should not be used by client code.

Opportunistic reuse is encouraged, but only for the purposes of testing or other specialized uses. Normal creation should occur through org.geotools.core.FeatureCollections.newCollection() allowing applications to customize any generated collections.

Parameters:
id - may be null ... feature id
featureType - optional, may be null
Method Detail

getBounds

public ReferencedEnvelope getBounds()
Gets the bounding box for the features in this feature collection.

Specified by:
getBounds in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
the envelope of the geometries contained by this feature collection.

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)

add

public boolean add(SimpleFeature o)
Ensures that this collection contains the specified element (optional operation). Returns true if this collection changed as a result of the call. (Returns false if this collection does not permit duplicates and already contains the specified element.)

Collections that support this operation may place limitations on what elements may be added to this collection. In particular, some collections will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. Collection classes should clearly specify in their documentation any restrictions on what elements may be added.

If a collection refuses to add a particular element for any reason other than that it already contains the element, it must throw an exception (rather than returning false). This preserves the invariant that a collection always contains the specified element after this call returns.

Specified by:
add in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
o - element whose presence in this collection is to be ensured.
Returns:
true if this collection changed as a result of the call
See Also:
Collection.add(Object)

add

protected boolean add(SimpleFeature feature,
                      boolean fire)

addAll

public boolean addAll(Collection collection)
Adds all of the elements in the specified collection to this collection (optional operation). The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified collection is this collection, and this collection is nonempty.)

Specified by:
addAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
collection - elements to be inserted into this collection.
Returns:
true if this collection changed as a result of the call
See Also:
#add(Object)

addAll

public boolean addAll(FeatureCollection collection)
Specified by:
addAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
See Also:
FeatureCollection.addAll(Collection)

clear

public void clear()
Removes all of the elements from this collection (optional operation). This collection will be empty after this method returns unless it throws an exception.

Specified by:
clear in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
See Also:
Collection.clear()

contains

public boolean contains(Object o)
Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).

Specified by:
contains in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
o - element whose presence in this collection is to be tested.
Returns:
true if this collection contains the specified element
See Also:
Collection.contains(Object)

containsAll

public boolean containsAll(Collection collection)
Test for collection membership.

Specified by:
containsAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
collection -
Returns:
true if collection is completly covered
See Also:
Collection.containsAll(Collection)

isEmpty

public boolean isEmpty()
Returns true if this collection contains no elements.

Specified by:
isEmpty in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
true if this collection contains no elements
See Also:
Collection.isEmpty()

iterator

public Iterator iterator()
Returns an iterator over the elements in this collection. There are no guarantees concerning the order in which the elements are returned (unless this collection is an instance of some class that provides a guarantee).

Specified by:
iterator in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
an Iterator over the elements in this collection

features

public FeatureIterator<SimpleFeature> features()
Gets a FeatureIterator of this feature collection. This allows iteration without having to cast.

Specified by:
features in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
the FeatureIterator for this collection.

remove

public boolean remove(Object o)
Removes a single instance of the specified element from this collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if this collection contains one or more such elements. Returns true if this collection contained the specified element (or equivalently, if this collection changed as a result of the call).

Specified by:
remove in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
o - element to be removed from this collection, if present.
Returns:
true if this collection changed as a result of the call
See Also:
Collection.remove(Object)

removeAll

public boolean removeAll(Collection collection)
Removes all this collection's elements that are also contained in the specified collection (optional operation). After this call returns, this collection will contain no elements in common with the specified collection.

Specified by:
removeAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
collection - elements to be removed from this collection.
Returns:
true if this collection changed as a result of the call
See Also:
remove(Object), contains(Object)

retainAll

public boolean retainAll(Collection collection)
Retains only the elements in this collection that are contained in the specified collection (optional operation). In other words, removes from this collection all of its elements that are not contained in the specified collection.

Specified by:
retainAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
collection - elements to be retained in this collection.
Returns:
true if this collection changed as a result of the call
See Also:
remove(Object), contains(Object)

size

public int size()
Returns the number of elements in this collection. If this collection contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:
size in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
the number of elements in this collection
See Also:
Collection.size()

toArray

public Object[] toArray()
Returns an array containing all of the elements in this collection. If the collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

The returned array will be "safe" in that no references to it are maintained by this collection. (In other words, this method must allocate a new array even if this collection is backed by an array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Specified by:
toArray in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
an array containing all of the elements in this collection
See Also:
Collection.toArray()

toArray

public Object[] toArray(Object[] a)
Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array. If the collection fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this collection.

If this collection fits in the specified array with room to spare (i.e., the array has more elements than this collection), the element in the array immediately following the end of the collection is set to null. This is useful in determining the length of this collection only if the caller knows that this collection does not contain any null elements.)

If this collection makes any guarantees as to what order its elements are returned by its iterator, this method must return the elements in the same order.

Like the toArray method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs

Suppose l is a List known to contain only strings. The following code can be used to dump the list into a newly allocated array of String:

     String[] x = (String[]) v.toArray(new String[0]);
 

Note that toArray(new Object[0]) is identical in function to toArray().

Specified by:
toArray in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
a - the array into which the elements of this collection are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.
Returns:
an array containing the elements of this collection
See Also:
Collection.toArray(Object[])

close

public void close(FeatureIterator<SimpleFeature> close)
Description copied from interface: FeatureCollection
Clean up after any resources associated with this FeatureIterator in a manner similar to JDO collections.

Example (safe) use:

 Iterator iterator = collection.iterator();
 try {
     for( Iterator i=collection.iterator(); i.hasNext();){
          Feature feature = i.hasNext();
          System.out.println( feature.getID() );
     }
 }
 finally {
     collection.close( iterator );
 }
 

Specified by:
close in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

close

public void close(Iterator close)
Description copied from interface: FeatureCollection
Clean up after any resources associated with this itterator in a manner similar to JDO collections.

Example (safe) use:

 Iterator iterator = collection.iterator();
 try {
     for( Iterator i=collection.iterator(); i.hasNext();){
          Feature feature = (Feature) i.hasNext();
          System.out.println( feature.getID() );
     }
 }
 finally {
     collection.close( iterator );
 }
 

Specified by:
close in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

reader

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

getCount

public int getCount()
             throws IOException
Throws:
IOException

collection

public FeatureCollection<SimpleFeatureType,SimpleFeature> collection()
                                                              throws IOException
Throws:
IOException

fids

public Set fids()
Optimization time ... grab the fid set so other can quickly test membership during removeAll/retainAll implementations.

Returns:
Set of fids.

accepts

public void accepts(FeatureVisitor visitor,
                    ProgressListener progress)
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

subCollection

public FeatureCollection<SimpleFeatureType,SimpleFeature> subCollection(Filter filter)
Will return an optimized subCollection based on access to the origional MemoryFeatureCollection.

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

Specified by:
subCollection in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
filter - Filter used to determine sub collection.
Returns:
FeatureCollection identified as subset.
Since:
GeoTools 2.2, Filter 1.1
See Also:
FeatureList

sort

public FeatureCollection<SimpleFeatureType,SimpleFeature> 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>
Parameters:
order - Filter 1.1 SortBy Construction of a Sort
Returns:
FeatureList sorted according to provided order
Since:
GeoTools 2.2, Filter 1.1

sort

public FeatureCollection<SimpleFeatureType,SimpleFeature> sort(SortBy2 order)
Allows for "Advanced" sort capabilities specific to the GeoTools platform!

Advanced in this case really means making use of a generic Expression, rather then being limited to PropertyName.

Parameters:
order - GeoTools SortBy
Returns:
FeatureList sorted according to provided order

purge

public void purge()
Description copied from interface: FeatureCollection
Close any outstanding resources released by this resources.

This method should be used with great caution, it is however available to allow the use of the ResourceCollection with algorthims that are unaware of the need to close iterators after use.

Example of using a normal Collections utility method:


 Collections.sort( collection );
 collection.purge();
 

Specified by:
purge in interface FeatureCollection<SimpleFeatureType,SimpleFeature>

validate

public void validate()

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
Description copied from interface: FeatureCollection
Adds a listener for collection events.

When this collection is backed by live data the event notification will follow the guidelines outlined by FeatureListner.

Specified by:
addListener in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
listener - The listener to add
Throws:
NullPointerException - If the listener is null.

removeListener

public final void removeListener(CollectionListener listener)
                          throws NullPointerException
Description copied from interface: FeatureCollection
Removes a listener for collection events.

Specified by:
removeListener in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
listener - The listener to remove
Throws:
NullPointerException - If the listener is null.

accepts

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

getSchema

public SimpleFeatureType getSchema()
Description copied from interface: FeatureCollection
The schema for the child features of this collection.

There is a difference between getFeatureType() and getSchema()represents the LCD FeatureType that best represents the contents of this collection.

The method getSchema() is named for compatability with the geotools 2.0 API. In the Geotools 2.2 time frame we should be able to replace this method with a careful check of getFeatureType() and its attributes.

Specified by:
getSchema in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
FeatureType describing the "common" schema to all child features of this collection


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