/**
 * 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.drill.common.logical.data;

import java.util.Iterator;
import java.util.List;

import org.apache.drill.common.logical.data.visitors.LogicalVisitor;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;

@JsonTypeName("union")
public class Union extends LogicalOperatorBase {
  private final List<LogicalOperator> inputs;
  private final boolean distinct;

  @JsonCreator
  public Union(@JsonProperty("inputs") List<LogicalOperator> inputs, @JsonProperty("distinct") Boolean distinct){
    this.inputs = inputs;
      for (LogicalOperator o : inputs) {
          o.registerAsSubscriber(this);
      }
    this.distinct = distinct == null ? false : distinct;
  }

  public List<LogicalOperator> getInputs() {
    return inputs;
  }

  public boolean isDistinct() {
    return distinct;
  }

    @Override
    public <T, X, E extends Throwable> T accept(LogicalVisitor<T, X, E> logicalVisitor, X value) throws E {
        return logicalVisitor.visitUnion(this, value);
    }

    @Override
    public Iterator<LogicalOperator> iterator() {
        return inputs.iterator();
    }


    public static Builder builder(){
      return new Builder();
    }

    public static class Builder extends AbstractBuilder<Union>{
      private List<LogicalOperator> inputs = Lists.newArrayList();
      private boolean distinct;

      public Builder addInput(LogicalOperator o){
        inputs.add(o);
        return this;
      }

      public Builder setDistinct(boolean distinct){
        this.distinct = distinct;
        return this;
      }

      @Override
      public Union build() {
        return new Union(inputs, distinct);
      }

    }

}