com.bigdata.rdf.sparql.ast.eval

Class AST2BOpBase

java.lang.Object

com.bigdata.rdf.sparql.ast.eval.AST2BOpBase

Direct Known Subclasses:

AST2BOpFilters

public class AST2BOpBase
extends Object

Base class provides support for triples, sids, and quads mode joins which was refactored from the old Rule2BOpUtility class.

Version:

$Id$

Author:

Bryan Thompson

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AST2BOpBase.Annotations Annotations used to mark named and default graph patterns on the IPredicates.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AST2BOpBase()

Method Summary

Methods

Modifier and Type	Method and Description
protected static PipelineOp	applyQueryHints(PipelineOp op, ASTBase node, AST2BOpContext ctx) Apply any query hints to the operator as annotations of that operator.
protected static PipelineOp	applyQueryHints(PipelineOp op, Properties nodeQueryHints, AST2BOpContext ctx) Apply any query hints to the operator as annotations of that operator.
protected static BOp[]	leftOrEmpty(PipelineOp left) Return either left wrapped as the sole member of an array or BOp.NOARGS iff left is null.

Methods inherited from class java.lang.Object

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

Constructor Detail

AST2BOpBase

protected AST2BOpBase()

Method Detail

leftOrEmpty

protected static BOp[] leftOrEmpty(PipelineOp left)

Return either left wrapped as the sole member of an array or BOp.NOARGS iff left is null.

Parameters:

left - The prior operator in the pipeline (optional).

Returns:

The array.

applyQueryHints

protected static PipelineOp applyQueryHints(PipelineOp op,
                         ASTBase node,
                         AST2BOpContext ctx)

Apply any query hints to the operator as annotations of that operator.

Note: This method is responsible for transferring query hints from ASTBase.getQueryHints() onto a generated PipelineOp.

Parameters:

op - The pipeline operator generated from some AST node.

node - The AST node from which the pipeline operator was generated (required). The query hints (from ASTBase.getQueryHints()) will be applied to that pipeline operator.

ctx - The evaluation context (ignored). Global query hints declared here will be applied to the generated pipeline operator. Global hints are applied first so they can be override by AST node specific hints.

Returns:

A copy of that operator to which the query hints (if any) have been applied. If there are no query hints then the original operator is returned.

See Also:

Clean up query hints

applyQueryHints

protected static PipelineOp applyQueryHints(PipelineOp op,
                         Properties nodeQueryHints,
                         AST2BOpContext ctx)

Apply any query hints to the operator as annotations of that operator.

Note: This method is responsible for transferring query hints from ASTBase.getQueryHints() onto a generated PipelineOp.

Note: This alternative form is for use within caller contexts in which (due to historical reasons) we have the query hints object for the AST node, but not the AST node itself. This pattern shows up in the join() methods since the StatementPatternNode is not passed through.

Parameters:

op - The pipeline operator generated from some AST node (required).

nodeQueryHints - The query hints for the AST node from which the pipeline operator was generated or its dominating operator context since not all operators have query hints applied (required).

ctx - The evaluation context (ignored). Global query hints declared here will be applied to the generated pipeline operator. Global hints are applied first so they can be override by AST node specific hints.

Returns:

A copy of that operator to which the query hints (if any) have been applied. If there are no query hints then the original operator is returned.

See Also:

Clean up query hints