io.druid.sql.calcite.planner.PlannerResult Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets 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 io.druid.sql.calcite.planner;
import com.google.common.base.Supplier;
import io.druid.java.util.common.guava.Sequence;
import org.apache.calcite.rel.type.RelDataType;
import java.util.concurrent.atomic.AtomicBoolean;
public class PlannerResult
{
private final Supplier> resultsSupplier;
private final RelDataType rowType;
private final AtomicBoolean didRun = new AtomicBoolean();
public PlannerResult(final Supplier> resultsSupplier, final RelDataType rowType)
{
this.resultsSupplier = resultsSupplier;
this.rowType = rowType;
}
public Sequence run()
{
if (!didRun.compareAndSet(false, true)) {
// Safety check.
throw new IllegalStateException("Cannot run more than once");
}
return resultsSupplier.get();
}
public RelDataType rowType()
{
return rowType;
}
}