solr/core/src/java/org/apache/solr/handler/sql/SolrProject.java

/*
 * 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.solr.handler.sql;

import org.apache.calcite.adapter.java.JavaTypeFactory;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptCost;
import org.apache.calcite.plan.RelOptPlanner;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.Project;
import org.apache.calcite.rel.metadata.RelMetadataQuery;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.util.Pair;

import java.util.List;

/**
 * Implementation of {@link org.apache.calcite.rel.core.Project} relational expression in Solr.
 */
class SolrProject extends Project implements SolrRel {
  SolrProject(RelOptCluster cluster, RelTraitSet traitSet,
              RelNode input, List<? extends RexNode> projects, RelDataType rowType) {
    super(cluster, traitSet, input, projects, rowType);
    assert getConvention() == SolrRel.CONVENTION;
    assert getConvention() == input.getConvention();
  }

  @Override
  public Project copy(RelTraitSet traitSet, RelNode input, List<RexNode> projects, RelDataType rowType) {
    return new SolrProject(getCluster(), traitSet, input, projects, rowType);
  }

  @Override
  public RelOptCost computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq) {
    return super.computeSelfCost(planner, mq).multiplyBy(0.1);
  }

  public void implement(Implementor implementor) {
    implementor.visitChild(0, getInput());
    final SolrRules.RexToSolrTranslator translator = new SolrRules.RexToSolrTranslator(
        (JavaTypeFactory) getCluster().getTypeFactory(), SolrRules.solrFieldNames(getInput().getRowType()));
    for (Pair<RexNode, String> pair : getNamedProjects()) {
      final String name = pair.right;
      final String expr = pair.left.accept(translator);
      implementor.addFieldMapping(name, expr, false);
    }
  }
}