content: /*
   * 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.calcite.interpreter;
  
  import org.apache.calcite.rel.core.Union;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * Interpreter node that implements a
   * {@link org.apache.calcite.rel.core.Union}.
   *
   * @deprecated Use {@link org.apache.calcite.interpreter.SetOpNode}
   */
  @Deprecated // to be removed before 2.0
  public class UnionNode implements Node {
    private final ImmutableList<Source> sources;
    private final Sink sink;
    private final Union rel;
  
    public UnionNode(Compiler compiler, Union rel) {
      ImmutableList.Builder<Source> builder = ImmutableList.builder();
      for (int i = 0; i < rel.getInputs().size(); i++) {
        builder.add(compiler.source(rel, i));
      }
      this.sources = builder.build();
      this.sink = compiler.sink(rel);
      this.rel = rel;
    }
  
    @Override public void run() throws InterruptedException {
      final Set<Row> rows = rel.all ? null : new HashSet<>();
      for (Source source : sources) {
        Row row;
        while ((row = source.receive()) != null) {
          if (rows == null || rows.add(row)) {
            sink.send(row);
          }
        }
      }
    }
  }
  