exec/vector/src/main/java/org/apache/drill/exec/vector/accessor/writer/UnionMemberShim.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.drill.exec.vector.accessor.writer;

import org.apache.drill.common.types.TypeProtos.MinorType;
import org.apache.drill.exec.vector.ValueVector;
import org.apache.drill.exec.vector.complex.UnionVector;

/**
 * Retrieves the member vectors for a union vector.
 */
interface UnionMemberShim {

  ValueVector getMember(MinorType type);
  boolean isProjected();

  class UnionMemberShimImpl implements UnionMemberShim {
    private final UnionVector vector;

    protected UnionMemberShimImpl(UnionVector vector) {
      this.vector = vector;
    }

    @Override
    public ValueVector getMember(MinorType type) {
      return vector.getMember(type);
    }

    @Override
    public boolean isProjected() { return true; }
  }

  class DummyUnionMemberShim implements UnionMemberShim {

    @Override
    public ValueVector getMember(MinorType type) {
      return null;
    }

    @Override
    public boolean isProjected() { return false; }
  }

}