Class AbstractFeatureCollection
- Object
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- AbstractFeatureCollection
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- All Implemented Interfaces:
SimpleFeatureCollection
,FeatureCollection<SimpleFeatureType,SimpleFeature>
- Direct Known Subclasses:
ForceCoordinateSystemFeatureResults
,ListFeatureCollection
,MemoryFeatureCollection
,ReprojectFeatureResults
public abstract class AbstractFeatureCollection extends Object implements SimpleFeatureCollection
Implement a feature collection just based on provision of anIterator
.This implementation asks you to implement:
openIterator()
size()
- User interaction is provided by the public API for FeatureCollection:
features()
: makes use ofDelegateSimpleFeatureIterator
(if needed) to wrap your iterator up as a SimpleFeatureIterator for public use.
Collection
classes as a FeatureCollection.
- Author:
- Jody Garnett (LISAsoft)
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Field Summary
Fields Modifier and Type Field Description protected String
id
id used when serialized to gmlprotected SimpleFeatureType
schema
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Constructor Summary
Constructors Modifier Constructor Description protected
AbstractFeatureCollection(SimpleFeatureType memberType)
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
accepts(FeatureVisitor visitor, ProgressListener progress)
Visit the contents of a feature collection.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.abstract ReferencedEnvelope
getBounds()
Subclasses need to override this.String
getID()
ID used when serializing to GMLSimpleFeatureType
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()
Provides acess toopenIterator()
used to traverse collection contents.protected abstract Iterator<SimpleFeature>
openIterator()
Factory method used to open an iterator over collection contents for use byiterator()
andfeatures()
.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.Object[]
toArray()
Array of all the elements.<O> O[]
toArray(O[] a)
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Field Detail
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id
protected String id
id used when serialized to gml
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schema
protected SimpleFeatureType schema
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Constructor Detail
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AbstractFeatureCollection
protected AbstractFeatureCollection(SimpleFeatureType memberType)
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Method Detail
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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 interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Specified by:
features
in interfaceSimpleFeatureCollection
- Returns:
- A FeatureIterator.
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openIterator
protected abstract Iterator<SimpleFeature> openIterator()
Factory method used to open an iterator over collection contents for use byiterator()
andfeatures()
.If you return an instance of FeatureIterator some effort is taken to call the
FeatureIterator.close()
internally, however we cannot offer any assurance that client code usingiterator()
will perform the same check.- Returns:
- Iterator over collection contents
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size
public abstract int size()
Returns the number of elements in this collection.- Specified by:
size
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Returns:
- Number of items, or Interger.MAX_VALUE
- See Also:
Collection.size()
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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 interfaceFeatureCollection<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)
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containsAll
public boolean containsAll(Collection<?> c)
Returns true if this collection contains all of the elements in the specified collection.- Specified by:
containsAll
in interfaceFeatureCollection<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)
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iterator
public final Iterator<SimpleFeature> iterator()
Provides acess toopenIterator()
used to traverse collection contents.You are asked to perform the following check when finished with the iterator:
if( e instanceof FeatureIterator ){ (FeatureIterator>)iterator).close(); }
- Returns:
- Iterator traversing collection contents
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isEmpty
public boolean isEmpty()
Description copied from interface:FeatureCollection
Returns true if this feature collection contains no features.- Specified by:
isEmpty
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Returns:
- true if this collection contains no elements.
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toArray
public Object[] toArray()
Array of all the elements.- Specified by:
toArray
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Returns:
- an array containing all of the elements in this collection.
- See Also:
Collection.toArray()
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toArray
public <O> O[] toArray(O[] a)
- Specified by:
toArray
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- See Also:
Collection.toArray(Object[])
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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 interfaceFeatureCollection<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
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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:
The above recommended use is agreement with the Collections API precident of List.subList( start, end ).collection.subCollection( filter ).clear();
The results of subCollection:
- are to be considered unordered
- may be an ordered FeatureList if requested when sortBy is indicated
- Specified by:
subCollection
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Specified by:
subCollection
in interfaceSimpleFeatureCollection
- Returns:
- SimpleFeatureCollection identified as subset.
- See Also:
FeatureList
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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 interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Specified by:
sort
in interfaceSimpleFeatureCollection
- Parameters:
order
- Sort order- Returns:
- FeatureCollection sorted in the indicated order
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getID
public String getID()
Description copied from interface:FeatureCollection
ID used when serializing to GML- Specified by:
getID
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
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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 interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Returns:
- FeatureType describing the "common" schema to all child features of this collection
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getBounds
public abstract ReferencedEnvelope getBounds()
Subclasses need to override this.- Specified by:
getBounds
in interfaceFeatureCollection<SimpleFeatureType,SimpleFeature>
- Returns:
- An Envelope containing the total bounds of this collection.
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