com.github.anno4j.querying

Class QueryOptimizer

java.lang.Object

com.github.anno4j.querying.QueryOptimizer

public class QueryOptimizer
extends Object

Method Summary

Modifier and Type	Method and Description
static QueryOptimizer	getInstance()
String	optimizeFilters(String sparql) Optimizes the query in multiple ways: Redo FILTER (A&&B) as FILTER(A) FILTER(B) (as an expr list) Optimizes the FILTER disjunctions Rewrite an algebra expression to put filters as close to their bound variables
String	optimizeJoinOrder(String sparql) Optimizes the join order of the query
String	prettyPrint(String sparql) Reformats the SPARQL query for logging purpose

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static QueryOptimizer getInstance()

optimizeJoinOrder

public String optimizeJoinOrder(String sparql)

Optimizes the join order of the query

Parameters:

sparql - The SPARQL query

Returns:

The optimized SPARQL query

optimizeFilters

public String optimizeFilters(String sparql)

Optimizes the query in multiple ways:

1. Redo FILTER (A&&B) as FILTER(A) FILTER(B) (as an expr list)
2. Optimizes the FILTER disjunctions
3. Rewrite an algebra expression to put filters as close to their bound variables

Parameters:

sparql - The SPARQL query

Returns:

The optimized SPARQL query

prettyPrint

public String prettyPrint(String sparql)

Reformats the SPARQL query for logging purpose

Parameters:

sparql - The generated SPARQL query

Returns:

Formatted query