org.wikidata.wdtk.datamodel.implementation

Class StatementImpl

java.lang.Object

org.wikidata.wdtk.datamodel.implementation.StatementImpl

All Implemented Interfaces:

Statement

public class StatementImpl
extends Object
implements Statement

Jackson implementation of Statement. In JSON, the corresponding structures are referred to as "claim".

Author:

Fredo Erxleben, Antonin Delpeuch, Thomas Pellissier Tanon

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StatementImpl.PreStatement Helper class for deserializing statements from JSON.

Constructor Summary

Constructors

Constructor and Description
StatementImpl(String statementId, Snak mainsnak, EntityIdValue subjectId) TODO review the utility of this constructor.
StatementImpl(String statementId, StatementRank rank, Snak mainSnak, List<SnakGroup> qualifiers, List<Reference> references, EntityIdValue subjectId) Constructor.
StatementImpl(String statementId, StatementRank rank, Snak mainSnak, Map<String,List<Snak>> qualifiers, List<String> qualifiersOrder, List<Reference> references, EntityIdValue subjectId)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
Iterator<Snak>	getAllQualifiers() Returns an iterator over all qualifiers, without considering qualifier groups.
Claim	getClaim() Get the Claim object that this statement refers to.
Snak	getMainSnak() Main Snak of the statement.
List<SnakGroup>	getQualifiers() Groups of auxiliary Snaks, also known as qualifiers, that provide additional context information for this claim.
StatementRank	getRank()
List<Reference>	getReferences() Get a list of references for this Statement.
String	getStatementId() Return the id used to identify this statement.
EntityIdValue	getSubject() The subject that the claim refers to, e.g., the id of "Berlin".
Value	getValue() Convenience method to get the value of the statement's claim's main snak, or null if there is none.
int	hashCode()
String	toString()
Statement	withStatementId(String id) Returns the same statement, but with a different identifier.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

StatementImpl

public StatementImpl(String statementId,
                     StatementRank rank,
                     Snak mainSnak,
                     List<SnakGroup> qualifiers,
                     List<Reference> references,
                     EntityIdValue subjectId)

Constructor.

The statementId is used mainly for communication with a Wikibase site, in order to refer to statements of that site. When creating new statements that are not on any site, the empty string can be used.

Parameters:

statementId - the string id of the Statement: can be empty if the statement has not obtained it yet

rank - the rank of the Statement

mainSnak - the main snak for the Claim of the Statement

qualifiers - the snak groups for the qualifiers

references - the references for the Statement

subjectId - the subject of this Statement

StatementImpl

public StatementImpl(String statementId,
                     StatementRank rank,
                     Snak mainSnak,
                     Map<String,List<Snak>> qualifiers,
                     List<String> qualifiersOrder,
                     List<Reference> references,
                     EntityIdValue subjectId)

StatementImpl

public StatementImpl(String statementId,
                     Snak mainsnak,
                     EntityIdValue subjectId)

TODO review the utility of this constructor.

Method Detail

getClaim

public Claim getClaim()

Description copied from interface: Statement

Get the Claim object that this statement refers to.

Specified by:

getClaim in interface Statement

Returns:

the claim that this statement refers to

getSubject

public EntityIdValue getSubject()

Description copied from interface: Statement

The subject that the claim refers to, e.g., the id of "Berlin".

Specified by:

getSubject in interface Statement

Returns:

EntityId of the subject

getMainSnak

public Snak getMainSnak()

Description copied from interface: Statement

Main Snak of the statement. This Snak refers directly to the subject, e.g., the ValueSnak "Population: 3000000".

Specified by:

getMainSnak in interface Statement

Returns:

the main snak

getQualifiers

public List<SnakGroup> getQualifiers()

Description copied from interface: Statement

Groups of auxiliary Snaks, also known as qualifiers, that provide additional context information for this claim. For example, "as of: 2014" might be a temporal context given for a claim that provides a population number. The snaks are grouped by the property that they use.

Specified by:

getQualifiers in interface Statement

Returns:

list of snak groups

getAllQualifiers

public Iterator<Snak> getAllQualifiers()

Description copied from interface: Statement

Returns an iterator over all qualifiers, without considering qualifier groups. The relative order of qualifiers is preserved.

Specified by:

getAllQualifiers in interface Statement

Returns:

iterator over all qualifier snaks

getRank

public StatementRank getRank()

Specified by:

getRank in interface Statement

Returns:

the rank of the Statement

See Also:

StatementRank

getReferences

public List<Reference> getReferences()

Description copied from interface: Statement

Get a list of references for this Statement. Each reference is represented by a list of Snaks, which provide information about the reference.

Specified by:

getReferences in interface Statement

Returns:

the list of references

getStatementId

public String getStatementId()

Description copied from interface: Statement

Return the id used to identify this statement.

Statement ids are used by Wikibase to allow certain interactions though the API, especially the atomic modification of Statements (modifications of statements can be viewed as deletions followed by insertions, but doing this in several steps though the API is not practical). In the current Wikibase implementation, the id is a string that begins with the (sometimes lowercased) local ID of the subject of the statement, followed by a dollar sign and a randomly generated UUID. Thus statements of different subjects can never have the same id, and it is extremely unlikely that two statements of the one subject ever have the same id. However, it is possible that two statements with the same content differ in their id, since the id is not based on the content.

Wikidata Toolkit generally requires ids to be specified but you can use the empty string to indicate that a statement has no id. This will also be respected when serializing data as JSON, i.e., rather than setting the statement id to an empty string in JSON, the key will simply be omitted. This is useful for creating new statements through the API.

Callers should not make any assumptions about the stability of statement ids over time, or about the internal format of the ids.

Specified by:

getStatementId in interface Statement

Returns:

the statement string id

getValue

public Value getValue()

Description copied from interface: Statement

Convenience method to get the value of the statement's claim's main snak, or null if there is none.

Specified by:

getValue in interface Statement

Returns:

main value of the statement, or null

withStatementId

public Statement withStatementId(String id)

Description copied from interface: Statement

Returns the same statement, but with a different identifier. This is useful when the existing identifier was empty and we need to attribute one before creating the statement in a remote Wikibase instance.

Specified by:

withStatementId in interface Statement

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object