/**
 * 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.hadoop.hive.ql.exec.vector;

/**
 * The representation of a vectorized column of struct objects.
 *
 * Each field is represented by a separate inner ColumnVector. Since this
 * ColumnVector doesn't own any per row data other that the isNull flag, the
 * isRepeating only covers the isNull array.
 */
public class StructColumnVector extends ColumnVector {

  public ColumnVector[] fields;

  public StructColumnVector() {
    this(VectorizedRowBatch.DEFAULT_SIZE);
  }

  /**
   * Constructor for StructColumnVector
   *
   * @param len Vector length
   * @param fields the field column vectors
   */
  public StructColumnVector(int len, ColumnVector... fields) {
    super(len);
    this.fields = fields;
  }

  @Override
  public void flatten(boolean selectedInUse, int[] sel, int size) {
    flattenPush();
    for(int i=0; i < fields.length; ++i) {
      fields[i].flatten(selectedInUse, sel, size);
    }
    flattenNoNulls(selectedInUse, sel, size);
  }

  @Override
  public void setElement(int outElementNum, int inputElementNum,
                         ColumnVector inputVector) {
    if (inputVector.isRepeating) {
      inputElementNum = 0;
    }
    if (inputVector.noNulls || !inputVector.isNull[inputElementNum]) {
      isNull[outElementNum] = false;
      ColumnVector[] inputFields = ((StructColumnVector) inputVector).fields;
      for (int i = 0; i < inputFields.length; ++i) {
        fields[i].setElement(outElementNum, inputElementNum, inputFields[i]);
      }
    } else {
      noNulls = false;
      isNull[outElementNum] = true;
    }
  }

  @Override
  public void stringifyValue(StringBuilder buffer, int row) {
    if (isRepeating) {
      row = 0;
    }
    if (noNulls || !isNull[row]) {
      buffer.append('[');
      for(int i=0; i < fields.length; ++i) {
        if (i != 0) {
          buffer.append(", ");
        }
        fields[i].stringifyValue(buffer, row);
      }
      buffer.append(']');
    } else {
      buffer.append("null");
    }
  }

  @Override
  public void ensureSize(int size, boolean preserveData) {
    super.ensureSize(size, preserveData);
    for(int i=0; i < fields.length; ++i) {
      fields[i].ensureSize(size, preserveData);
    }
  }

  @Override
  public void reset() {
    super.reset();
    for(int i =0; i < fields.length; ++i) {
      fields[i].reset();
    }
  }

  @Override
  public void init() {
    super.init();
    for(int i =0; i < fields.length; ++i) {
      fields[i].init();
    }
  }

  @Override
  public void unFlatten() {
    super.unFlatten();
    for(int i=0; i < fields.length; ++i) {
      fields[i].unFlatten();
    }
  }

  @Override
  public void setRepeating(boolean isRepeating) {
    super.setRepeating(isRepeating);
    for(int i=0; i < fields.length; ++i) {
      fields[i].setRepeating(isRepeating);
    }
  }

  @Override
  public void shallowCopyTo(ColumnVector otherCv) {
    throw new UnsupportedOperationException(); // Implement if needed.
  }
}