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This module contains all API code. External dependencies should be limited. Any changes to public methods should be avoided. While the API module does not have compile time dependency on fluo-core, you must include fluo-core as a run-time dependency.
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/*
 * Copyright 2014 Fluo authors (see AUTHORS)
 * 
 * Licensed 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.fluo.api.data;

import java.io.Serializable;

import com.google.common.base.Preconditions;

/**
 * Represents all or a subset of the column family, column qualifier, and column visibility fields.
 * A column with no fields set is represented by Column.EMPTY. Column is immutable after it is
 * created.
 */
public class Column implements Comparable, Serializable {

  private static final long serialVersionUID = 1L;
  public static final Bytes UNSET = Bytes.of(new byte[0]);

  private Bytes family = UNSET;
  private Bytes qualifier = UNSET;
  private Bytes visibility = UNSET;

  public static final Column EMPTY = new Column();

  /**
   * Creates an empty Column where family, qualifier and visibility are not set
   */
  public Column() {}

  /**
   * Creates Column with only a family.
   */
  public Column(Bytes family) {
    Preconditions.checkNotNull(family, "Family must not be null");
    this.family = family;
  }

  /**
   * Creates Column with only a family. String parameter will be encoded as UTF-8.
   */
  public Column(String family) {
    this(Bytes.of(family));
  }

  /**
   * Creates Column with a family and qualifier.
   */
  public Column(Bytes family, Bytes qualifier) {
    Preconditions.checkNotNull(family, "Family must not be null");
    Preconditions.checkNotNull(qualifier, "Qualifier must not be null");
    this.family = family;
    this.qualifier = qualifier;
  }

  /**
   * Creates Column with a family and qualifier. String parameters will be encoded as UTF-8.
   */
  public Column(String family, String qualifier) {
    this(Bytes.of(family), Bytes.of(qualifier));
  }

  /**
   * Creates Column with family, qualifier, and visibility
   */
  public Column(Bytes family, Bytes qualifier, Bytes visibility) {
    Preconditions.checkNotNull(family, "Family must not be null");
    Preconditions.checkNotNull(qualifier, "Qualifier must not be null");
    Preconditions.checkNotNull(visibility, "Visibility must not be null");
    this.family = family;
    this.qualifier = qualifier;
    this.visibility = visibility;
  }

  /**
   * Creates Column with family, qualifier, and visibility. String parameters will be encoded as
   * UTF-8.
   */
  public Column(String family, String qualifier, String visibility) {
    this(Bytes.of(family), Bytes.of(qualifier), Bytes.of(visibility));
  }

  /**
   * Returns true if family is set
   */
  public boolean isFamilySet() {
    return family != UNSET;
  }

  /**
   * Retrieves Column Family (in Bytes). Returns Bytes.EMPTY if not set.
   */
  public Bytes getFamily() {
    if (!isFamilySet()) {
      return Bytes.EMPTY;
    }
    return family;
  }

  /**
   * Returns true if qualifier is set
   */
  public boolean isQualifierSet() {
    return qualifier != UNSET;
  }

  /**
   * Retrieves Column Qualifier (in Bytes). Returns Bytes.EMPTY if not set.
   */
  public Bytes getQualifier() {
    if (!isQualifierSet()) {
      return Bytes.EMPTY;
    }
    return qualifier;
  }

  /**
   * Returns true if visibility is set.
   */
  public boolean isVisibilitySet() {
    return visibility != UNSET;
  }

  /**
   * Retrieves Column Visibility (in Bytes). Returns Bytes.EMPTY if not set.
   */
  public Bytes getVisibility() {
    if (!isVisibilitySet()) {
      return Bytes.EMPTY;
    }
    return visibility;
  }

  @Override
  public String toString() {
    return family + " " + qualifier + " " + visibility;
  }

  @Override
  public int hashCode() {
    return family.hashCode() + 31 * (31 * qualifier.hashCode() + visibility.hashCode());
  }

  @Override
  public int compareTo(Column other) {
    int result = family.compareTo(other.family);
    if (result == 0) {
      result = qualifier.compareTo(other.qualifier);
      if (result == 0) {
        result = visibility.compareTo(other.visibility);
      }
    }
    return result;
  }

  @Override
  public boolean equals(Object o) {
    if (o instanceof Column) {
      Column oc = (Column) o;
      return family.equals(oc.getFamily()) && qualifier.equals(oc.getQualifier())
          && visibility.equals(oc.getVisibility());
    }
    return false;
  }
}