| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.jena.sparql.algebra.optimize; |
| |
| import java.util.ArrayList ; |
| import java.util.HashSet ; |
| import java.util.List ; |
| import java.util.Set ; |
| |
| import org.apache.jena.atlas.logging.Log ; |
| import org.apache.jena.sparql.algebra.Op ; |
| import org.apache.jena.sparql.algebra.TransformCopy ; |
| import org.apache.jena.sparql.algebra.op.OpDisjunction ; |
| import org.apache.jena.sparql.algebra.op.OpFilter ; |
| import org.apache.jena.sparql.expr.E_LogicalOr ; |
| import org.apache.jena.sparql.expr.Expr ; |
| import org.apache.jena.sparql.expr.ExprList ; |
| |
| /**Filter disjunction. |
| * Merge with TransformFilterImprove |
| */ |
| |
| public class TransformFilterDisjunction extends TransformCopy |
| { |
| public TransformFilterDisjunction() {} |
| |
| @Override |
| public Op transform(OpFilter opFilter, final Op subOp) |
| { |
| ExprList exprList = opFilter.getExprs() ; |
| |
| // First pass - any disjunctions at all? |
| boolean processDisjunction = false ; |
| for ( Expr expr : exprList ) |
| { |
| if ( isDisjunction(expr) ) |
| { |
| processDisjunction = true ; |
| break ; |
| } |
| } |
| |
| // Still may be a disjunction in a form we don't optimize. |
| if ( ! processDisjunction ) |
| return super.transform(opFilter, subOp) ; |
| |
| ExprList exprList2 = new ExprList() ; |
| Op newOp = subOp ; |
| // remember what's been seen so that FILTER(?x = <x> || ?x = <x> ) does not result in two transforms. |
| Set<Expr> doneSoFar = new HashSet<>() ; |
| |
| for ( Expr expr : exprList ) |
| { |
| if ( ! isDisjunction(expr) ) |
| { |
| // Assignment there? |
| exprList2.add(expr) ; |
| continue ; |
| } |
| |
| // // Relies on expression equality. |
| // if ( doneSoFar.contains(expr) ) |
| // continue ; |
| // // Must be canonical: ?x = <x> is the same as <x> = ?x |
| // doneSoFar.add(expr) ; |
| |
| Op op2 = expandDisjunction(expr, newOp) ; |
| |
| if ( op2 != null ) |
| newOp = op2 ; |
| } |
| |
| if ( exprList2.isEmpty() ) |
| return newOp ; |
| |
| // There should have been at least on disjunction. |
| if ( newOp == subOp ) { |
| Log.warn(this, "FilterDisjunction assumption failure: didn't find a disjunction after all") ; |
| return super.transform(opFilter, subOp) ; |
| } |
| |
| |
| // Failed. These a was one or more expressions we couldn't handle. |
| // So the full pattern is going to be executed anyway. |
| //return super.transform(super.transform(opFilter, subOp)) ; |
| |
| |
| // Put the non-disjunctions outside the disjunction and the pattern rewrite. |
| Op opOther = OpFilter.filterBy(exprList2, newOp) ; |
| if ( opOther instanceof OpFilter) { |
| return opOther ; |
| } |
| |
| // opOther is not a filter any more - should not happen but to isolate from future changes ... |
| Log.warn(this, "FilterDisjunction assumption failure: not a filter after processing disjunction/other mix") ; |
| return super.transform(opFilter, subOp) ; |
| } |
| |
| private boolean isDisjunction(Expr expr) |
| { |
| return ( expr instanceof E_LogicalOr ) ; |
| } |
| |
| // Todo: |
| // 1 - convert TransformEqualityFilter to use ExprLib for testing. |
| // 2 - Scan for safe equality filters in disjunction. |
| |
| public static Op expandDisjunction(Expr expr, Op subOp) |
| { |
| // if ( !( expr instanceof E_LogicalOr ) ) |
| // return null ; |
| |
| List<Expr> exprList = explodeDisjunction(new ArrayList<Expr>(), expr) ; |
| |
| // All disjunctions - some can be done efficiently via assignments, some can not. |
| // Really should only do if every disjunction can turned into a assign-grounded pattern |
| // otherwise the full is done anyway. |
| |
| List<Expr> exprList2 = null ; |
| Op op = null ; |
| for ( Expr e : exprList ) |
| { |
| Op op2 = TransformFilterEquality.processFilter(e, subOp) ; |
| if ( op2 == null ) |
| { |
| // Not done. |
| if ( exprList2 == null ) |
| exprList2 = new ArrayList<>() ; |
| exprList2.add(e) ; |
| //continue ; |
| // Can't do one so don't do any as the original pattern is still executed. |
| } |
| |
| op = OpDisjunction.create(op, op2) ; |
| } |
| |
| if ( exprList2 != null && !exprList2.isEmpty() ) |
| { |
| // These are left as disjunctions. |
| Expr eOther = null ; |
| for ( Expr e : exprList2 ) |
| { |
| if ( eOther == null ) |
| eOther = e ; |
| else |
| eOther = new E_LogicalOr(eOther, e) ; |
| } |
| Op opOther = OpFilter.filter(eOther, subOp) ; |
| op = OpDisjunction.create(op, opOther) ; |
| } |
| |
| return op ; |
| } |
| |
| /** Explode a expr into a list of disjunctions */ |
| private static List<Expr> explodeDisjunction(List<Expr> exprList, Expr expr) |
| { |
| if ( !( expr instanceof E_LogicalOr ) ) |
| { |
| exprList.add(expr) ; |
| return exprList ; |
| } |
| |
| E_LogicalOr exprOr = (E_LogicalOr)expr ; |
| Expr e1 = exprOr.getArg1() ; |
| Expr e2 = exprOr.getArg2() ; |
| explodeDisjunction(exprList, e1) ; |
| explodeDisjunction(exprList, e2) ; |
| return exprList ; |
| } |
| } |