com.bigdata.rdf.sparql.ast.hints

Class AbstractQueryHint<T>

java.lang.Object

com.bigdata.rdf.sparql.ast.hints.AbstractQueryHint<T>

All Implemented Interfaces:

IQueryHint<T>

Direct Known Subclasses:

AbstractBooleanQueryHint, AbstractChunkSizeHint, AbstractStringQueryHint, BasicDoubleQueryHint, BasicIntQueryHint, BasicLongQueryHint, OptimizerQueryHint

public abstract class AbstractQueryHint<T>
extends Object
implements IQueryHint<T>

Base class for query hints.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractQueryHint(String name, T defaultValue)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	_setAnnotation(IEvaluationContext ctx, QueryHintScope scope, ASTBase op, String name, T value) Set an annotation on the AST node.
protected void	_setQueryHint(IEvaluationContext ctx, QueryHintScope scope, ASTBase op, String name, T value) Set the query hint.
T	getDefault() The default value for this query hint (many query hints provide overrides of defaults).
String	getName() The name of the query hint.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.bigdata.rdf.sparql.ast.hints.IQueryHint

handle, validate

Constructor Detail

AbstractQueryHint

protected AbstractQueryHint(String name,
                 T defaultValue)

Parameters:

name - The name of the query hint (required).

defaultValue - The default value (optional).

Method Detail

getName

public final String getName()

Description copied from interface: IQueryHint

The name of the query hint.

Specified by:

getName in interface IQueryHint<T>

getDefault

public final T getDefault()

Description copied from interface: IQueryHint

The default value for this query hint (many query hints provide overrides of defaults).

Specified by:

getDefault in interface IQueryHint<T>

_setQueryHint

protected final void _setQueryHint(IEvaluationContext ctx,
                 QueryHintScope scope,
                 ASTBase op,
                 String name,
                 T value)

Set the query hint.

Note: Query hints are Properties objects and their values are Strings. The value will be converted to a String.

Note: Unlike annotations, query hints are propagated en-mass from an AST node to the generated pipeline operator.

Parameters:

name - The name of the query hint.

value - The value for the query hint.

_setAnnotation

protected final void _setAnnotation(IEvaluationContext ctx,
                  QueryHintScope scope,
                  ASTBase op,
                  String name,
                  T value)

Set an annotation on the AST node.

Note: Annotations are attached directly to the AST node. They are interpreted during query plan generation. Unlike the query hints, the annotations are not automatically transferred to the generated pipeline operators. Instead, they typically control the behavior of the IASTOptimizers.

Parameters:

op - The AST node.

name - The name of the annotation.

value - The value of the annotation.