Module org.apache.sis.storage
Package org.apache.sis.storage.aggregate

Class ConcatenatedFeatureSet

Object
AbstractResource
AbstractFeatureSet
ConcatenatedFeatureSet
All Implemented Interfaces:
Data­Set, Feature­Set, Resource
public class ConcatenatedFeatureSet extends AbstractFeatureSet
Exposes a sequence of Feature­Sets as a single one. The concatenation is built from an array or collection of input feature sets, copied verbatim in iteration order and without removal of duplicated elements. All input feature sets must share a common type, or at least a common super-type. The feature type of this concatenated set will be the most specific type found among all input feature sets.

Identification

There is no identifier since this feature set is a computation result.

Multi-threading

Concatenated feature set is immutable and thread-safe if all input feature sets are immutable and thread-safe.
Since:
1.0

  • Constructor Details

    • ConcatenatedFeatureSet

      protected ConcatenatedFeatureSet(Resource parent, FeatureSet[] sources) throws DataStoreException
      Creates a new feature set as a concatenation of the sequence of features given by the sources. This constructor does not verify that the given sources array contains at least two elements; this verification must be done by the caller. This constructor retains the given sources array by direct reference; clone, if desired, shall be done by the caller.
      Parameters:
      parent - the parent resource, or null if none.
      sources - the sequence of feature sets to expose in a single set. Must neither be null, empty nor contain a single element only.
      Throws:
      Data­Store­Exception - if given feature sets does not share any common type.

  • Method Details

    • create

      public static FeatureSet create(FeatureSet... sources) throws DataStoreException
      Creates a new feature set as a concatenation of the sequence of features given by the sources. The given array shall be non-empty. If the array contains only 1 element, that element is returned.
      Parameters:
      sources - the sequence of feature sets to expose in a single set.
      Returns:
      the concatenation of given feature set.
      Throws:
      Data­Store­Exception - if given feature sets does not share any common type.

    • create

      public static FeatureSet create(Collection<? extends FeatureSet> sources) throws DataStoreException
      Creates a new feature set as a concatenation of the sequence of features given by the sources. The given collection shall be non-empty. If the collection contains only 1 element, that element is returned.
      Parameters:
      sources - the sequence of feature sets to expose in a single set.
      Returns:
      the concatenation of given feature set.
      Throws:
      Data­Store­Exception - if given feature sets does not share any common type.

    • getType

      public DefaultFeatureType getType()
      Returns the most specific feature type common to all feature sets given to the constructor.
      Returns:
      the common type of all features returned by this set.

    • getFeatureCount

      public OptionalLong getFeatureCount()
      Returns an estimation of the number of features in this set, or an empty value if unknown. This is the sum of the estimations provided by all source sets, or empty if at least one source could not provide an estimation.
      Overrides:
      get­Feature­Count in class Abstract­Feature­Set
      Returns:
      estimation of the number of features.

    • features

      public Stream<AbstractFeature> features(boolean parallel)
      Returns a stream of all features contained in this concatenated dataset. If the parallel argument is false, then datasets are traversed in the order they were specified at construction time. If the parallel argument is true, then datasets are traversed in no determinist order. If an error occurred while reading the feature instances from a source, then the error is wrapped in a Backing­Store­Exception.
      Parameters:
      parallel - true for a parallel stream, or false for a sequential stream.
      Returns:
      all features contained in this dataset.

    • subset

      public FeatureSet subset(Query query) throws DataStoreException
      Requests a subset of features and/or feature properties from this resource.
      Parameters:
      query - definition of feature and feature properties filtering applied at reading time.
      Returns:
      resulting subset of features (never null).
      Throws:
      Data­Store­Exception - if an error occurred while processing the query.
      See Also:

    • getEnvelope

      public final Optional<Envelope> getEnvelope() throws DataStoreException
      Returns the union of the envelopes in all aggregated feature sets. This method tries to find a CRS common to all feature sets. If no common CRS can be found, then the envelope is absent.
      Specified by:
      get­Envelope in interface Data­Set
      Overrides:
      get­Envelope in class Abstract­Resource
      Returns:
      union of envelopes from all dependencies.
      Throws:
      Data­Store­Exception - if an error occurred while computing the envelope.

    • createMetadata

      protected Metadata createMetadata() throws DataStoreException
      Invoked in a synchronized block the first time that get­Metadata() is invoked. The default implementation adds the information documented in the parent class, then adds the dependencies as lineages.
      Overrides:
      create­Metadata in class Abstract­Feature­Set
      Returns:
      the newly created metadata, or null if unknown.
      Throws:
      Data­Store­Exception - if an error occurred while reading metadata from the data stores.

    • clearCache

      protected void clearCache()
      Clears any cache in this resource, forcing the data to be recomputed when needed again. This method should be invoked if the data in underlying data store changed.
      Overrides:
      clear­Cache in class Abstract­Resource