/*
* 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 com.hp.hpl.jena.sparql.algebra.op;
import org.apache.jena.atlas.lib.Lib ;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.algebra.OpVisitor ;
import com.hp.hpl.jena.sparql.algebra.Transform ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.core.VarExprList ;
import com.hp.hpl.jena.sparql.expr.Expr ;
import com.hp.hpl.jena.sparql.sse.Tags ;
import com.hp.hpl.jena.sparql.util.NodeIsomorphismMap ;
/** This is the operation in stadard SPARQL 1.1
* OpAssign is specifically in support of LET.
*/
public class OpExtend extends Op1
{
private VarExprList assignments ;
// There factory operations compress nested assignments if possible.
// Not possible if it's the reassignment of something already assigned.
// Or we could implement something like (let*).
static public Op extend(Op op, Var var, Expr expr)
{
if ( ! ( op instanceof OpExtend ) )
return createExtend(op, var, expr) ;
OpExtend opAssign = (OpExtend)op ;
if ( opAssign.assignments.contains(var) )
return createExtend(op, var, expr) ;
opAssign.assignments.add(var, expr) ;
return opAssign ;
}
static public Op extend(Op op, VarExprList exprs)
{
if ( ! ( op instanceof OpExtend ) )
return createExtend(op, exprs) ;
OpExtend opAssign = (OpExtend)op ;
for ( Var var : exprs.getVars() )
{
if ( opAssign.assignments.contains(var) )
return createExtend(op, exprs) ;
}
opAssign.assignments.addAll(exprs) ;
return opAssign ;
}
/** Make a OpExtend - guaranteed to return an OpExtend */
public static OpExtend extendDirect(Op op, VarExprList exprs)
{
return new OpExtend(op, exprs) ;
}
static private Op createExtend(Op op, Var var, Expr expr)
{
VarExprList x = new VarExprList() ;
x.add(var, expr) ;
return new OpExtend(op, x) ;
}
static private Op createExtend(Op op, VarExprList exprs)
{
// Create, copying the var-expr list
VarExprList x = new VarExprList() ;
x.addAll(exprs) ;
return new OpExtend(op, x) ;
}
private OpExtend(Op subOp)
{
super(subOp) ;
assignments = new VarExprList() ;
}
private OpExtend(Op subOp, VarExprList exprs)
{
super(subOp) ;
assignments = exprs ;
}
@Override
public String getName() { return Tags.tagExtend ; }
// Need to protect this with checking for var already used.
// See the factories in statics above.
private void add(Var var, Expr expr)
{ assignments.add(var, expr) ; }
public VarExprList getVarExprList() { return assignments ; }
@Override
public int hashCode()
{ return assignments.hashCode() ^ getSubOp().hashCode() ; }
@Override
public void visit(OpVisitor opVisitor)
{ opVisitor.visit(this) ; }
@Override
public Op1 copy(Op subOp)
{
OpExtend op = new OpExtend(subOp, new VarExprList(getVarExprList())) ;
return op ;
}
@Override
public boolean equalTo(Op other, NodeIsomorphismMap labelMap)
{
if ( ! ( other instanceof OpExtend) )
return false ;
OpExtend assign = (OpExtend)other ;
if ( ! Lib.equal(assignments, assign.assignments) )
return false ;
return getSubOp().equalTo(assign.getSubOp(), labelMap) ;
}
@Override
public Op apply(Transform transform, Op subOp)
{ return transform.transform(this, subOp) ; }
}