/*
* Copyright Aduna (http://www.aduna-software.com/) (c) 2008.
*
* Licensed under the Aduna BSD-style license.
*/
package org.openrdf.sail.rdbms.algebra.factories;
import static org.openrdf.model.vocabulary.XMLSchema.DECIMAL;
import static org.openrdf.model.vocabulary.XMLSchema.DOUBLE;
import static org.openrdf.model.vocabulary.XMLSchema.FLOAT;
import static org.openrdf.model.vocabulary.XMLSchema.INTEGER;
import static org.openrdf.sail.rdbms.algebra.base.SqlExprSupport.in;
import static org.openrdf.sail.rdbms.algebra.base.SqlExprSupport.sqlNull;
import static org.openrdf.sail.rdbms.algebra.base.SqlExprSupport.str;
import static org.openrdf.sail.rdbms.algebra.base.SqlExprSupport.unsupported;
import org.openrdf.model.Literal;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.query.algebra.Datatype;
import org.openrdf.query.algebra.Lang;
import org.openrdf.query.algebra.MathExpr;
import org.openrdf.query.algebra.QueryModelNode;
import org.openrdf.query.algebra.Str;
import org.openrdf.query.algebra.ValueConstant;
import org.openrdf.query.algebra.ValueExpr;
import org.openrdf.query.algebra.Var;
import org.openrdf.query.algebra.helpers.QueryModelVisitorBase;
import org.openrdf.sail.rdbms.algebra.DatatypeColumn;
import org.openrdf.sail.rdbms.algebra.SqlCase;
import org.openrdf.sail.rdbms.algebra.SqlNull;
import org.openrdf.sail.rdbms.algebra.TrueValue;
import org.openrdf.sail.rdbms.algebra.base.SqlExpr;
import org.openrdf.sail.rdbms.exceptions.UnsupportedRdbmsOperatorException;
/**
* Creates a datatype SQL expression.
*
* @author James Leigh
*/
public class DatatypeExprFactory extends QueryModelVisitorBase<UnsupportedRdbmsOperatorException> {
protected SqlExpr result;
public SqlExpr createDatatypeExpr(ValueExpr expr)
throws UnsupportedRdbmsOperatorException
{
result = null;
if (expr == null) {
return new SqlNull();
}
expr.visit(this);
if (result == null) {
return new SqlNull();
}
return result;
}
@Override
public void meet(Datatype node) {
result = sqlNull();
}
@Override
public void meet(Lang node)
throws UnsupportedRdbmsOperatorException
{
result = sqlNull();
}
@Override
public void meet(MathExpr node)
throws UnsupportedRdbmsOperatorException
{
boolean divide = node.getOperator().equals(MathExpr.MathOp.DIVIDE);
ValueExpr left = node.getLeftArg();
ValueExpr right = node.getRightArg();
SqlCase sqlCase = new SqlCase();
sqlCase.when(in(str(DOUBLE), type(left), type(right)), str(DOUBLE));
sqlCase.when(in(str(FLOAT), type(left), type(right)), str(FLOAT));
sqlCase.when(in(str(DECIMAL), type(left), type(right)), str(DECIMAL));
sqlCase.when(new TrueValue(), divide ? str(DECIMAL) : str(INTEGER));
result = sqlCase;
}
@Override
public void meet(Str node)
throws UnsupportedRdbmsOperatorException
{
result = sqlNull();
}
@Override
public void meet(ValueConstant vc) {
result = valueOf(vc.getValue());
}
@Override
public void meet(Var var) {
if (var.getValue() == null) {
result = new DatatypeColumn(var);
}
else {
result = valueOf(var.getValue());
}
}
@Override
protected void meetNode(QueryModelNode arg)
throws UnsupportedRdbmsOperatorException
{
throw unsupported(arg);
}
private SqlExpr valueOf(Value value) {
if (value instanceof Literal) {
URI datatype = ((Literal)value).getDatatype();
if (datatype != null) {
return str(datatype.stringValue());
}
}
return sqlNull();
}
private SqlExpr type(ValueExpr expr)
throws UnsupportedRdbmsOperatorException
{
return createDatatypeExpr(expr);
}
}