com.hp.hpl.jena.sparql.expr
Class ExprLib

java.lang.Object
  com.hp.hpl.jena.sparql.expr.ExprLib

public class ExprLib
extends Object

Constructor Summary

ExprLib()

Method Summary

static Expr	foldConstants(Expr expr) Attempt to fold any sub-expressions of the Expr.
static boolean	isAssignmentSafeEquality(Expr expr) Decide whether an expression is safe for using a a graph substitution.
static boolean	isAssignmentSafeEquality(Expr expr, boolean graphHasStringEquality, boolean graphHasNumercialValueEquality)
static Expr	replaceAggregateByVariable(Expr expr) transform an expression that may involve aggregates into one that just uses the variable for the aggregate
static ExprList	replaceAggregateByVariable(ExprList exprs) transform expressions that may involve aggregates into one that just uses the variable for the aggregate

Methods inherited from class java.lang.Object

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

Constructor Detail

ExprLib

public ExprLib()

Method Detail

foldConstants

public static Expr foldConstants(Expr expr)

Attempt to fold any sub-expressions of the Expr. Return an expression that is euqivalent to the argument but maybe simpler.

Parameters:

expr -

Returns:

Expression

replaceAggregateByVariable

public static Expr replaceAggregateByVariable(Expr expr)

transform an expression that may involve aggregates into one that just uses the variable for the aggregate

replaceAggregateByVariable

public static ExprList replaceAggregateByVariable(ExprList exprs)

transform expressions that may involve aggregates into one that just uses the variable for the aggregate

isAssignmentSafeEquality

public static boolean isAssignmentSafeEquality(Expr expr)

Decide whether an expression is safe for using a a graph substitution. Need to be careful about value-like tests when the graph is not matched in a value fashion.

isAssignmentSafeEquality

public static boolean isAssignmentSafeEquality(Expr expr,
                                               boolean graphHasStringEquality,
                                               boolean graphHasNumercialValueEquality)

Parameters:

graphHasStringEquality - True if the graph triple matching equates xsd:string and plain literal

graphHasNumercialValueEquality - True if the graph triple matching equates numeric values