org.apache.sis.util

Interface Emptiable

All Known Implementing Classes:

AbstractCompleteness, AbstractContentInformation, AbstractElement, AbstractEnvelope, AbstractGeographicExtent, AbstractGeolocationInformation, AbstractIdentification, AbstractLogicalConsistency, AbstractMetadata, AbstractParty, AbstractPositionalAccuracy, AbstractResult, AbstractSpatialRepresentation, AbstractTemporalAccuracy, AbstractThematicAccuracy, DefaultAbsoluteExternalPositionalAccuracy, DefaultAccuracyOfATimeMeasurement, DefaultAcquisitionInformation, DefaultAddress, DefaultAggregateInformation, DefaultAlgorithm, DefaultApplicationSchemaInformation, DefaultAssociatedResource, DefaultAttributeGroup, DefaultBand, DefaultBoundingPolygon, DefaultBrowseGraphic, DefaultCitation, DefaultCitationDate, DefaultCompletenessCommission, DefaultCompletenessOmission, DefaultConceptualConsistency, DefaultConformanceResult, DefaultConstraints, DefaultContact, DefaultCoupledResource, DefaultCoverageDescription, DefaultCoverageResult, DefaultDataFile, DefaultDataIdentification, DefaultDataQuality, DefaultDigitalTransferOptions, DefaultDimension, DefaultDistribution, DefaultDistributor, DefaultDomainConsistency, DefaultEnvironmentalRecord, DefaultEvent, DefaultExtendedElementInformation, DefaultExtent, DefaultFeatureCatalogueDescription, DefaultFeatureTypeInfo, DefaultFeatureTypeList, DefaultFormat, DefaultFormatConsistency, DefaultGCP, DefaultGCPCollection, DefaultGeographicBoundingBox, DefaultGeographicDescription, DefaultGeometricObjects, DefaultGeorectified, DefaultGeoreferenceable, DefaultGriddedDataPositionalAccuracy, DefaultGridSpatialRepresentation, DefaultIdentifier, DefaultImageDescription, DefaultIndividual, DefaultInstrument, DefaultKeywordClass, DefaultKeywords, DefaultLegalConstraints, DefaultLineage, DefaultMaintenanceInformation, DefaultMedium, DefaultMetadata, DefaultMetadataExtensionInformation, DefaultMetadataScope, DefaultNominalResolution, DefaultNonQuantitativeAttributeAccuracy, DefaultObjective, DefaultOnlineResource, DefaultOperation, DefaultOperationChainMetadata, DefaultOperationMetadata, DefaultOrganisation, DefaultPlan, DefaultPlatform, DefaultPlatformPass, DefaultPortrayalCatalogueReference, DefaultProcessing, DefaultProcessStep, DefaultProcessStepReport, DefaultQuantitativeAttributeAccuracy, DefaultQuantitativeResult, DefaultRangeDimension, DefaultRangeElementDescription, DefaultRelativeInternalPositionalAccuracy, DefaultReleasability, DefaultRepresentativeFraction, DefaultRequestedDate, DefaultRequirement, DefaultResolution, DefaultResponsibility, DefaultResponsibleParty, DefaultSampleDimension, DefaultScope, DefaultScope, DefaultScopeDescription, DefaultSecurityConstraints, DefaultSeries, DefaultServiceIdentification, DefaultSource, DefaultSpatialTemporalExtent, DefaultStandardOrderProcess, DefaultTelephone, DefaultTemporalConsistency, DefaultTemporalExtent, DefaultTemporalValidity, DefaultThematicClassificationCorrectness, DefaultTopologicalConsistency, DefaultUsability, DefaultUsage, DefaultVectorSpatialRepresentation, DefaultVerticalExtent, Envelope2D, GeneralEnvelope, ImmutableEnvelope, ISOMetadata, MeasurementRange, ModifiableMetadata, NumberRange, Range

public interface Emptiable

Interface of classes for which empty instances may exist. This interface is typically used for filtering empty elements from a collection or a tree of objects. Some examples of emptiable classes are:

• Range when the lower bounds is equals to the upper bounds and at least one bound is exclusive.
• Abstract­Metadata when no property value has been given to the metadata, or all properties are themselves empty.
• Abstract­Envelope when the span, surface or volume inside the envelope is zero.

SIS collections do not implement this interface even if they provide a is­Empty() method, for consistency with collections in java.util and other libraries. This policy avoid duplicated calls to is­Empty() methods when the caller need to check for both Collection and Emptiable interfaces.

Since:

0.4

Defined in the sis-utility module

Method Summary

Modifier and Type	Method and Description
boolean	isEmpty() Returns true if this instance is empty.

Method Detail

isEmpty

boolean isEmpty()

Returns true if this instance is empty. The definition of "emptiness" may vary between implementations. For example Default­Geographic­Bounding­Box.is­Empty() returns true if all values are Na­N (i.e. uninitialized) while Abstract­Envelope.is­Empty() returns true if the geometric surface is zero.

Returns:

true if this instance is empty, or false otherwise.