org.geotools.feature.collection
Class AdaptorFeatureCollection

Object
  extended by AdaptorFeatureCollection
All Implemented Interfaces:
SimpleFeatureCollection, FeatureCollection<SimpleFeatureType,SimpleFeature>

public abstract class AdaptorFeatureCollection
extends Object
implements SimpleFeatureCollection

Implement a feature collection just based on provision of iterator.

You will need to implement the following methods:

Author:
Jody Garnett (LISAsoft)

Field Summary
protected  String id
          id used when serialized to gml
protected  SimpleFeatureType schema
           
 
Constructor Summary
AdaptorFeatureCollection(String id, SimpleFeatureType memberType)
           
 
Method Summary
 void accepts(FeatureVisitor visitor, ProgressListener progress)
          Accepts a visitor, which then visits each feature in the collection.
 void close(FeatureIterator<SimpleFeature> close)
           
 void close(Iterator close)
          Clean up after any resources assocaited with this iteartor in a manner similar to JDO collections.
 void close(SimpleFeatureIterator close)
           
protected abstract  void closeIterator(Iterator<SimpleFeature> close)
          Please override to cleanup after your own iterators, and any used resources.
 void closeIterator(SimpleFeatureIterator close)
           
 boolean contains(Object o)
          Returns true if this collection contains the specified element.
 boolean containsAll(Collection c)
          Returns true if this collection contains all of the elements in the specified collection.
 SimpleFeatureIterator features()
          Obtain a SimpleFeatureIterator of the Features within this SimpleFeatureCollection.
 ReferencedEnvelope getBounds()
          Subclasses need to override this.
 String getID()
          ID used when serializing to GML
 SimpleFeatureType getSchema()
          The schema for the child feature members of this collection.
 boolean isEmpty()
          Returns true if this feature collection contains no features.
 Iterator<SimpleFeature> iterator()
          Please implement!
protected abstract  Iterator<SimpleFeature> openIterator()
          Open an Iterator, we will call close( iterator ).
abstract  int size()
          Returns the number of elements in this collection.
 SimpleFeatureCollection sort(SortBy order)
          Obtained sorted contents.
 SimpleFeatureCollection subCollection(Filter filter)
          SimpleFeatureCollection "view" indicated by provided filter.
 SimpleFeatureCollection subList(Filter filter)
           
 Object[] toArray()
          Array of all the elements.
 Object[] toArray(Object[] a)
           
 String toString()
          Returns a string representation of this collection.
 
Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

id

protected String id
id used when serialized to gml


schema

protected SimpleFeatureType schema
Constructor Detail

AdaptorFeatureCollection

public AdaptorFeatureCollection(String id,
                                SimpleFeatureType memberType)
Method Detail

features

public SimpleFeatureIterator features()
Description copied from interface: SimpleFeatureCollection
Obtain a SimpleFeatureIterator of the Features within this SimpleFeatureCollection.

The implementation of FeatureIterator must adhere to the rules of fail-fast concurrent modification. In addition (to allow for resource backed collections) the SimpleFeatureIterator.close() method must be called.

Example use:


 SimpleFeatureIterator iterator=collection.features();
 try {
     while( iterator.hasNext()  ){
          SimpleFeature feature = iterator.next();
          System.out.println( feature.getID() );
     }
 }
 finally {
     iterator.close();
 }
 

Specified by:
features in interface SimpleFeatureCollection
Specified by:
features in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
A FeatureIterator.

close

public void close(FeatureIterator<SimpleFeature> close)

close

public void close(SimpleFeatureIterator close)

closeIterator

public void closeIterator(SimpleFeatureIterator close)

accepts

public void accepts(FeatureVisitor visitor,
                    ProgressListener progress)
             throws IOException
Accepts a visitor, which then visits each feature in the collection.

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

subList

public SimpleFeatureCollection subList(Filter filter)

subCollection

public SimpleFeatureCollection subCollection(Filter filter)
Description copied from interface: FeatureCollection
SimpleFeatureCollection "view" indicated by provided filter.

The contents of the returned SimpleFeatureCollection are determined by applying the provider Filter to the entire contents of this FeatureCollection. The result is "live" and modifications will be shared.

This method is used cut down on the number of filter based methods required for a useful SimpleFeatureCollection construct. The FeatureCollections returned really should be considered as a temporary "view" used to control the range of a removeAll, or modify operation.

Example Use:


 collection.subCollection( filter ).clear();
 
The above recommended use is agreement with the Collections API precident of List.subList( start, end ).

The results of subCollection:

Specified by:
subCollection in interface SimpleFeatureCollection
Specified by:
subCollection in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
SimpleFeatureCollection identified as subset.
See Also:
FeatureList

sort

public SimpleFeatureCollection sort(SortBy order)
Description copied from interface: FeatureCollection
Obtained sorted contents.

This method may not be supported by all implementations, consider the use of FeatureSource.features( Query ).

Specified by:
sort in interface SimpleFeatureCollection
Specified by:
sort in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
order - Sort order
Returns:
FeatureCollection sorted in the indicated order

isEmpty

public boolean isEmpty()
Description copied from interface: FeatureCollection
Returns true if this feature collection contains no features.

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

contains

public boolean contains(Object o)
Returns true if this collection contains the specified element. .

This implementation iterates over the elements in the collection, checking each element in turn for equality with the specified element.

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

toArray

public Object[] toArray()
Array of all the elements.

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)
Specified by:
toArray in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
See Also:
Collection.toArray(Object[])

containsAll

public boolean containsAll(Collection c)
Returns true if this collection contains all of the elements in the specified collection.

Specified by:
containsAll in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Parameters:
c - collection to be checked for containment in this collection.
Returns:
true if this collection contains all of the elements in the specified collection.
Throws:
NullPointerException - if the specified collection is null.
See Also:
contains(Object)

toString

public String toString()
Returns a string representation of this collection.

Overrides:
toString in class Object
Returns:
a string representation of this collection.

iterator

public final Iterator<SimpleFeature> iterator()
Please implement!

Note: If you return a ResourceIterator, the default implemntation of close( Iterator ) will know what to do.


size

public abstract int size()
Returns the number of elements in this collection.

Specified by:
size in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
Number of items, or Interger.MAX_VALUE
See Also:
Collection.size()

close

public final void close(Iterator close)
Clean up after any resources assocaited with this iteartor 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 );
 }
 

Parameters:
close -

openIterator

protected abstract Iterator<SimpleFeature> openIterator()
Open an Iterator, we will call close( iterator ).

Please subclass to provide your own iterator - note iterator() is implemented to call open() and track the results in for later purge().

Returns:
Iterator based on resource use

closeIterator

protected abstract void closeIterator(Iterator<SimpleFeature> close)
Please override to cleanup after your own iterators, and any used resources.

As an example if the iterator was working off a File then the inputstream should be closed.

Subclass must call super.close( close ) to allow the list of open iterators to be adjusted.

Parameters:
close - Iterator, will not be null

getID

public String getID()
Description copied from interface: FeatureCollection
ID used when serializing to GML

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

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.

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

getBounds

public ReferencedEnvelope getBounds()
Subclasses need to override this.

Specified by:
getBounds in interface FeatureCollection<SimpleFeatureType,SimpleFeature>
Returns:
An Envelope containing the total bounds of this collection.


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