/*
* 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.eigenbase.rel;
import java.util.*;
import org.eigenbase.relopt.*;
import org.eigenbase.reltype.*;
import org.eigenbase.rex.RexBuilder;
import org.eigenbase.rex.RexNode;
import net.hydromatic.optiq.util.BitSets;
/**
* <code>TableAccessRelBase</code> is an abstract base class for implementations
* of {@link TableAccessRel}.
*/
public abstract class TableAccessRelBase extends AbstractRelNode {
//~ Instance fields --------------------------------------------------------
/**
* The table definition.
*/
protected final RelOptTable table;
//~ Constructors -----------------------------------------------------------
protected TableAccessRelBase(
RelOptCluster cluster,
RelTraitSet traits,
RelOptTable table) {
super(cluster, traits);
this.table = table;
if (table.getRelOptSchema() != null) {
cluster.getPlanner().registerSchema(table.getRelOptSchema());
}
}
/**
* Creates a TableAccessRelBase by parsing serialized output.
*/
protected TableAccessRelBase(RelInput input) {
this(input.getCluster(), input.getTraitSet(), input.getTable("table"));
}
//~ Methods ----------------------------------------------------------------
@Override public double getRows() {
return table.getRowCount();
}
@Override public RelOptTable getTable() {
return table;
}
@Override public List<RelCollation> getCollationList() {
return table.getCollationList();
}
@Override public boolean isKey(BitSet columns) {
return table.isKey(columns);
}
@Override public RelOptCost computeSelfCost(RelOptPlanner planner) {
double dRows = table.getRowCount();
double dCpu = dRows + 1; // ensure non-zero cost
double dIo = 0;
return planner.getCostFactory().makeCost(dRows, dCpu, dIo);
}
@Override public RelDataType deriveRowType() {
return table.getRowType();
}
@Override public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw)
.item("table", table.getQualifiedName());
}
/**
* Projects a subset of the fields of the table, and also asks for "extra"
* fields that were not included in the table's official type.
*
* <p>The default implementation assumes that tables cannot do either of
* these operations, therefore it adds a {@link ProjectRel}, projecting
* {@code NULL} values for the extra fields.</p>
*
* <p>Sub-classes, representing table types that have these capabilities,
* should override.</p>
*
* @param fieldsUsed Bitmap of the fields desired by the consumer
* @param extraFields Extra fields, not advertised in the table's row-type,
* wanted by the consumer
* @return Relational expression that projects the desired fields
*/
public RelNode project(BitSet fieldsUsed, Set<RelDataTypeField> extraFields,
RelFactories.ProjectFactory projectFactory) {
final int fieldCount = getRowType().getFieldCount();
if (fieldsUsed.equals(BitSets.range(fieldCount))
&& extraFields.isEmpty()) {
return this;
}
List<RexNode> exprList = new ArrayList<RexNode>();
List<String> nameList = new ArrayList<String>();
RexBuilder rexBuilder = getCluster().getRexBuilder();
final List<RelDataTypeField> fields = getRowType().getFieldList();
// Project the subset of fields.
for (int i : BitSets.toIter(fieldsUsed)) {
RelDataTypeField field = fields.get(i);
exprList.add(rexBuilder.makeInputRef(this, i));
nameList.add(field.getName());
}
// Project nulls for the extra fields. (Maybe a sub-class table has
// extra fields, but we don't.)
for (RelDataTypeField extraField : extraFields) {
exprList.add(
rexBuilder.ensureType(
extraField.getType(),
rexBuilder.constantNull(),
true));
nameList.add(extraField.getName());
}
return projectFactory.createProject(this, exprList, nameList);
}
@Override
public RelNode accept(RelShuttle shuttle) {
return shuttle.visit(this);
}
}
// End TableAccessRelBase.java