org.eclipse.viatra.query.runtime.matchers.backend

Class QueryEvaluationHint

java.lang.Object

org.eclipse.viatra.query.runtime.matchers.backend.QueryEvaluationHint

public class QueryEvaluationHint
extends java.lang.Object

Provides VIATRA Query with additional hints on how a query should be evaluated. The same hint can be provided to multiple queries.

This class is immutable. Overriding options will create a new instance.

Here be dragons: for advanced users only.

Constructor Summary

Constructors

Constructor and Description
QueryEvaluationHint(IQueryBackendFactory queryBackendFactory, java.util.Map<java.lang.String,java.lang.Object> backendHints) Deprecated. As of 1.5, use QueryEvaluationHint(Map, IQueryBackendFactory) instead. String-keyed hint setting map will be ignored.
QueryEvaluationHint(java.util.Map<QueryHintOption,java.lang.Object> backendHintSettings, IQueryBackendFactory queryBackendFactory) Specifies the suggested query backend, and value settings for additional backend-specific options.

Method Summary

Modifier and Type	Method and Description
IMatcherCapability	calculateRequiredCapability(PQuery query) Extract the requested capabilities
boolean	equals(java.lang.Object obj)
java.util.Map<java.lang.String,java.lang.Object>	getBackendHints() Deprecated. As of 1.5, string keys are no longer available. Use QueryHintOption instead
java.util.Map<QueryHintOption,java.lang.Object>	getBackendHintSettings() Each entry in the immutable map overrides backend-specific options regarding query evaluation.
IQueryBackendFactory	getQueryBackendFactory() A suggestion for choosing the query evaluator algorithm.
<HintValue> HintValue	getValueOrDefault(QueryHintOption<HintValue> option) Returns the value of the given hint option from the given hint collection, or the default value if not defined.
<HintValue> HintValue	getValueOrNull(QueryHintOption<HintValue> option) Returns the value of the given hint option from the given hint collection, or null if not defined.
int	hashCode()
boolean	isOptionOverridden(QueryHintOption<?> option) Returns whether the given hint option is overridden.
QueryEvaluationHint	overrideBy(QueryEvaluationHint overridingHint) Override values in this hint and return a consolidated instance.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryEvaluationHint

public QueryEvaluationHint(java.util.Map<QueryHintOption,java.lang.Object> backendHintSettings,
                           IQueryBackendFactory queryBackendFactory)

Specifies the suggested query backend, and value settings for additional backend-specific options. Both parameters are optional (can be null).

Parameters:

backendHintSettings - each entry in the map overrides backend-specific options regarding query evaluation (null-valued map entries permitted to erase hints); passing null means default options associated with the query

queryBackendFactory - overrides the query evaluator algorithm; passing null retains the default algorithm associated with the query

Since:

1.5

QueryEvaluationHint

public QueryEvaluationHint(IQueryBackendFactory queryBackendFactory,
                           java.util.Map<java.lang.String,java.lang.Object> backendHints)

Deprecated. As of 1.5, use QueryEvaluationHint(Map, IQueryBackendFactory) instead. String-keyed hint setting map will be ignored.

Method Detail

getQueryBackendFactory

public IQueryBackendFactory getQueryBackendFactory()

A suggestion for choosing the query evaluator algorithm.

Can be null.

getBackendHints

public java.util.Map<java.lang.String,java.lang.Object> getBackendHints()

Deprecated. As of 1.5, string keys are no longer available. Use QueryHintOption instead

Each entry in the map overrides backend-specific options regarding query evaluation.

The map can be null if empty. Null-valued map entries are also permitted to erase hints.

getBackendHintSettings

public java.util.Map<QueryHintOption,java.lang.Object> getBackendHintSettings()

Each entry in the immutable map overrides backend-specific options regarding query evaluation.

The map is non-null, even if empty. Null-valued map entries are also permitted to erase hints via overrideBy(QueryEvaluationHint).

Since:

1.5

overrideBy

public QueryEvaluationHint overrideBy(QueryEvaluationHint overridingHint)

Override values in this hint and return a consolidated instance.

Since:

1.4

isOptionOverridden

public boolean isOptionOverridden(QueryHintOption<?> option)

Returns whether the given hint option is overridden.

Since:

1.5

getValueOrNull

public <HintValue> HintValue getValueOrNull(QueryHintOption<HintValue> option)

Returns the value of the given hint option from the given hint collection, or null if not defined.

Since:

1.5

getValueOrDefault

public <HintValue> HintValue getValueOrDefault(QueryHintOption<HintValue> option)

Returns the value of the given hint option from the given hint collection, or the default value if not defined. Intended to be called by backends to find out the definitive value that should be considered.

Since:

1.5

calculateRequiredCapability

public IMatcherCapability calculateRequiredCapability(PQuery query)

Extract the requested capabilities

Since:

1.4

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object