Interface PQuery
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- All Superinterfaces:
PQueryHeader
,PTraceable
- All Known Subinterfaces:
InitializablePQuery
- All Known Implementing Classes:
BaseGeneratedEMFPQuery
,BasePQuery
,GenericEMFPatternPQuery
,GenericSingleConstraintPQuery
public interface PQuery extends PQueryHeader, PTraceable
Internal representation of a query / graph pattern (using a constraint system formalism), to be interpreted by a query evaluator (IQueryBackend
). End-users of VIATRA Query should access a query as an IQuerySpecification instead.PQuerys are definitions of queries usable inside pattern descriptions. Such description always has (a non-null) name. The query itself is defined as a (non-empty) set of
PBody
instances, the result is the disjunction of the singlePBody
instances.A PQuery might be constructed from erroneous patterns or might be uninitialized - this is represented by its status.
- Since:
- 0.8.0
- No Implement:
- This interface is not intended to be implemented by clients. Use
BasePQuery
as a base class instead.
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Nested Class Summary
Nested Classes Modifier and Type Interface Description static class
PQuery.PQueryStatus
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
checkMutability()
Before a modification operation is executed, a mutability check is performed (via thegetStatus()
implementation, and in case of problems anIllegalStateException
is thrown.void
ensureInitialized()
If the query definition is uninitialized, initializes it.java.util.Set<PQuery>
getAllReferredQueries()
Returns all queries required to evaluate this query (transitively).java.util.Set<PQuery>
getDirectReferredQueries()
Returns all queries directly referred in the constraints.PDisjunction
getDisjunctBodies()
Returns all bodies associated with the query in their canonical form.QueryEvaluationHint
getEvaluationHints()
Optional hints regarding the query evaluation strategy, to be interpreted by the query engine.java.util.List<PProblem>
getPProblems()
Returns a list describing the problems that were found in this query.PQuery.PQueryStatus
getStatus()
Returns the initialization status of the definitionjava.util.Set<TypeJudgement>
getTypeGuarantees()
Type information, expressed on query parameters, that all matches of the query are guaranteed to respect.boolean
isMutable()
An option to check mutability of the query.java.util.List<java.lang.Object>
publishedAs()
Returns the end-user query specification API objects that wrap this query.-
Methods inherited from interface org.eclipse.viatra.query.runtime.matchers.psystem.queries.PQueryHeader
getAllAnnotations, getAnnotationsByName, getFirstAnnotationByName, getFullyQualifiedName, getParameter, getParameterNames, getParameters, getPositionOfParameter, getSimpleName, getVisibility
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Method Detail
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getDisjunctBodies
PDisjunction getDisjunctBodies()
Returns all bodies associated with the query in their canonical form. If called multiple times, the same set with the same contents will be returned.
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getDirectReferredQueries
java.util.Set<PQuery> getDirectReferredQueries()
Returns all queries directly referred in the constraints. They are all required to evaluate this query- Returns:
- a non-null, but possibly empty list of query definitions
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getAllReferredQueries
java.util.Set<PQuery> getAllReferredQueries()
Returns all queries required to evaluate this query (transitively).- Returns:
- a non-null, but possibly empty list of query definitions
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getStatus
PQuery.PQueryStatus getStatus()
Returns the initialization status of the definition
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getPProblems
java.util.List<PProblem> getPProblems()
Returns a list describing the problems that were found in this query.TODO: formulate invariant connecting
getPProblems()
andgetStatus()
.- Returns:
- a non-null, but possibly empty list of problems
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checkMutability
void checkMutability()
Before a modification operation is executed, a mutability check is performed (via thegetStatus()
implementation, and in case of problems anIllegalStateException
is thrown.
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isMutable
boolean isMutable()
An option to check mutability of the query. It can be used to avoid getting anIllegalStateException
by the execution ofcheckMutability()
.- Returns:
- true if the query specification is still editable
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getEvaluationHints
QueryEvaluationHint getEvaluationHints()
Optional hints regarding the query evaluation strategy, to be interpreted by the query engine.To ensure the possibility of external overrides, the evaluation engine should not directly consult this field, but use an
IQueryBackendHintProvider
instead.
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getTypeGuarantees
java.util.Set<TypeJudgement> getTypeGuarantees()
Type information, expressed on query parameters, that all matches of the query are guaranteed to respect.At the very minimum, this should include the declared types of the parameters.
The type judgement tuples shall contain the parameter index, NOT the
PParameter
object.- Returns:
- a non-null set of type judgements that the query guarantees for its matches
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ensureInitialized
void ensureInitialized()
If the query definition is uninitialized, initializes it.- Throws:
ViatraQueryRuntimeException
- if initialization of query specification fails
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publishedAs
java.util.List<java.lang.Object> publishedAs()
Returns the end-user query specification API objects that wrap this query.Intended for traceability and debug purposes, not part of normal operation. Returned list is intended to be appended during query specification construction time.
- Returns:
- a non-null, but possibly empty list of query specification objects;
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