Object
AbstractResource
AbstractFeatureSet
JoinFeatureSet
- All Implemented Interfaces:
DataSet,FeatureSet,Resource
Features containing association to features from two different sources, joined by a SQL-like
JOIN condition.
Each feature in this FeatureSet contains two or three properties:
- An optional identifier created from the identifiers of the left and right features.
- Zero or one association to a "left" feature.
- Zero or one association to a "right" feature.
JoinFeatureSet instance when a value from
leftProperty in the first feature is equal to a value from rightProperty in the second feature.
Implementation note
If iterations in one feature set is cheaper than iterations in the other feature set, then the "costly" or largerFeatureSet should be on the left side and the "cheap" FeatureSet should be on the right side.
This implementation is read-only.
- Since:
- 1.0
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic enumSpecifies whether values on both sides are required (inner join), or only one side (outer join). -
Field Summary
FieldsModifier and TypeFieldDescriptionfinal BinaryComparisonOperator<AbstractFeature> The join condition in the form property from left feature = property from right feature.final FeatureSetThe first source of features.final FeatureSetThe second source of features.Fields inherited from class AbstractResource
listeners -
Constructor Summary
ConstructorsConstructorDescriptionJoinFeatureSet(Resource parent, FeatureSet left, String leftAlias, FeatureSet right, String rightAlias, JoinFeatureSet.Type joinType, BinaryComparisonOperator<AbstractFeature> condition, Map<String, ?> featureInfo) Creates a new feature set joining the two given sets. -
Method Summary
Modifier and TypeMethodDescriptionprotected voidClears any cache in this resource, forcing the data to be recomputed when needed again.protected MetadataInvoked in a synchronized block the first time thatgetMetadata()is invoked.features(boolean parallel) Returns a stream of all features contained in this dataset.Returns the union of the envelopes in all aggregated feature sets.Specifies whether values on both sides are required (inner join), or only one side (outer join).getType()Returns a description of properties that are common to all features in this dataset.Methods inherited from class AbstractFeatureSet
getFeatureCount, getIdentifierMethods inherited from class AbstractResource
addListener, getMetadata, getSynchronizationLock, removeListenerMethods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface FeatureSet
subsetMethods inherited from interface Resource
addListener, getMetadata, removeListener
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Field Details
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left
The first source of features. -
right
The second source of features. -
condition
The join condition in the form property from left feature = property from right feature. This condition specifies also if the comparison is case sensitive and how to compare multi-values.
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Constructor Details
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JoinFeatureSet
public JoinFeatureSet(Resource parent, FeatureSet left, String leftAlias, FeatureSet right, String rightAlias, JoinFeatureSet.Type joinType, BinaryComparisonOperator<AbstractFeature> condition, Map<String, ?> featureInfo) throws DataStoreExceptionCreates a new feature set joining the two given sets. ThefeatureInfomap defines the name, description or other information for theFeatureTypecreated by this method. It can contain all the properties described inDefaultFeatureTypeplus the following ones:"identifierDelimiter"— string to insert between left and right identifiers in the identifiers generated by the join operation. If this property is not specified, then no identifier will be generated."identifierPrefix"— string to insert at the beginning of join identifiers (optional)."identifierSuffix"— string to insert at the end of join identifiers (optional).
- Parameters:
parent- the parent resource, ornullif none.left- the first source of features. This is often (but not necessarily) the largest set.leftAlias- name of the associations to theleftfeatures, ornullfor a default name.right- the second source of features. Should be the set in which iterations are cheapest.rightAlias- name of the associations to therightfeatures, ornullfor a default name.joinType- whether values on both sides are required (inner join), or only one side (outer join).condition- join condition as property from left feature = property from right feature.featureInfo- information about theFeatureTypeof this feature set.- Throws:
DataStoreException- if an error occurred while creating the feature set.
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Method Details
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getJoinType
Specifies whether values on both sides are required (inner join), or only one side (outer join).- Returns:
- whether values on both sides are required (inner join), or only one side (outer join).
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getType
Returns a description of properties that are common to all features in this dataset. This type may contain one identifier and always contains two associations, to the left andrightset of features respectively.- Returns:
- a description of properties that are common to all features in this dataset.
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features
Returns a stream of all features contained in this dataset.- Parameters:
parallel-truefor a parallel stream (if supported), orfalsefor a sequential stream.- Returns:
- all features contained in this dataset.
- Throws:
DataStoreException- if an error occurred while creating the stream.
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getEnvelope
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:
getEnvelopein interfaceDataSet- Overrides:
getEnvelopein classAbstractResource- Returns:
- union of envelopes from all dependencies.
- Throws:
DataStoreException- if an error occurred while computing the envelope.
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createMetadata
Invoked in a synchronized block the first time thatgetMetadata()is invoked. The default implementation adds the information documented in the parent class, then adds the dependencies as lineages.- Overrides:
createMetadatain classAbstractFeatureSet- Returns:
- the newly created metadata, or
nullif unknown. - Throws:
DataStoreException- if an error occurred while reading metadata from the data stores.
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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:
clearCachein classAbstractResource
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