ColumnInfo.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.hadoop.hive.ql.exec;

import java.io.Serializable;

import org.apache.hadoop.hive.common.StringInternUtils;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;

/**
 * Implementation for ColumnInfo which contains the internal name for the column
 * (the one that is used by the operator to access the column) and the type
 * (identified by a java class).
 **/

public class ColumnInfo implements Serializable {

  private static final long serialVersionUID = 1L;

  private String internalName;

  private String alias = null; // [optional] alias of the column (external name
  // as seen by the users)
  /**
   * Indicates whether the column is a skewed column.
   */
  private boolean isSkewedCol;

  /**
   * Store the alias of the table where available.
   */
  private String tabAlias;

  /**
   * Indicates whether the column is a virtual column.
   */
  private boolean isVirtualCol;

  private ObjectInspector objectInspector;

  private boolean isHiddenVirtualCol;

  private String typeName;

  public ColumnInfo() {
  }

  public ColumnInfo(String internalName, TypeInfo type, String tabAlias,
      boolean isVirtualCol) {
    this(internalName, type, tabAlias, isVirtualCol, false);
  }

  public ColumnInfo(String internalName, Class type, String tabAlias,
      boolean isVirtualCol) {
    this(internalName, TypeInfoFactory
        .getPrimitiveTypeInfoFromPrimitiveWritable(type), tabAlias,
        isVirtualCol, false);
  }

  public ColumnInfo(String internalName, TypeInfo type, String tabAlias,
      boolean isVirtualCol, boolean isHiddenVirtualCol) {
    this(internalName,
         TypeInfoUtils.getStandardWritableObjectInspectorFromTypeInfo(type),
         tabAlias,
         isVirtualCol,
         isHiddenVirtualCol);
  }

  public ColumnInfo(String internalName, ObjectInspector objectInspector,
      String tabAlias, boolean isVirtualCol) {
    this(internalName, objectInspector, tabAlias, isVirtualCol, false);
  }

  public ColumnInfo(String internalName, ObjectInspector objectInspector,
      String tabAlias, boolean isVirtualCol, boolean isHiddenVirtualCol) {
    this.internalName = internalName;
    this.objectInspector = objectInspector;
    this.tabAlias = tabAlias;
    this.isVirtualCol = isVirtualCol;
    this.isHiddenVirtualCol = isHiddenVirtualCol;
    setTypeName(getType().getTypeName());
  }

  public ColumnInfo(ColumnInfo columnInfo) {
    this.internalName = columnInfo.getInternalName();
    this.alias = columnInfo.getAlias();
    this.isSkewedCol = columnInfo.isSkewedCol();
    this.tabAlias = columnInfo.getTabAlias();
    this.isVirtualCol = columnInfo.getIsVirtualCol();
    this.isHiddenVirtualCol = columnInfo.isHiddenVirtualCol();
    this.setType(columnInfo.getType());
  }

  public String getTypeName() {
    return this.typeName;
  }

  public void setTypeName(String typeName) {
    this.typeName = StringInternUtils.internIfNotNull(typeName);
  }

  public TypeInfo getType() {
    return TypeInfoUtils.getTypeInfoFromObjectInspector(objectInspector);
  }

  public ObjectInspector getObjectInspector() {
    return objectInspector;
  }

  public String getInternalName() {
    return internalName;
  }

  public void setType(TypeInfo type) {
    objectInspector =
        TypeInfoUtils.getStandardWritableObjectInspectorFromTypeInfo(type);
    setTypeName(type.getTypeName());
  }

  public void setInternalName(String internalName) {
    this.internalName = internalName;
  }

  public String getTabAlias() {
    return tabAlias;
  }

  public boolean getIsVirtualCol() {
    return isVirtualCol;
  }

  public boolean isHiddenVirtualCol() {
    return isHiddenVirtualCol;
  }

  /**
   * Returns the string representation of the ColumnInfo.
   */
  @Override
  public String toString() {
    return internalName + ": " + typeName;
  }

  public void setAlias(String col_alias) {
    alias = StringInternUtils.internIfNotNull(col_alias);
  }

  public String getAlias() {
    return alias;
  }

  public void setTabAlias(String tabAlias) {
    this.tabAlias = tabAlias;
  }

  public void setVirtualCol(boolean isVirtualCol) {
    this.isVirtualCol = isVirtualCol;
  }

  public void setHiddenVirtualCol(boolean isHiddenVirtualCol) {
    this.isHiddenVirtualCol = isHiddenVirtualCol;
  }

  /**
   * @return the isSkewedCol
   */
  public boolean isSkewedCol() {
    return isSkewedCol;
  }

  /**
   * @param isSkewedCol the isSkewedCol to set
   */
  public void setSkewedCol(boolean isSkewedCol) {
    this.isSkewedCol = isSkewedCol;
  }

  private boolean checkEquals(Object obj1, Object obj2) {
    return obj1 == null ? obj2 == null : obj1.equals(obj2);
  }

  @Override
  public int hashCode() {
    return internalName.hashCode() + typeName.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    if (!(obj instanceof ColumnInfo) || (obj == null)) {
      return false;
    }

    ColumnInfo dest = (ColumnInfo)obj;
    if ((!checkEquals(internalName, dest.getInternalName())) ||
        (!checkEquals(tabAlias, dest.getTabAlias())) ||
        (!checkEquals(alias, dest.getAlias())) ||
        (!checkEquals(getType(), dest.getType())) ||
        (isSkewedCol != dest.isSkewedCol()) ||
        (isVirtualCol != dest.getIsVirtualCol()) ||
        (isHiddenVirtualCol != dest.isHiddenVirtualCol())) {
      return false;
    }

    return true;
  }

  public boolean internalEquals(ColumnInfo dest) {
    if (dest == null) {
      return false;
    }

    if ((!checkEquals(internalName, dest.getInternalName())) ||
        (!checkEquals(getType(), dest.getType())) ||
        (isSkewedCol != dest.isSkewedCol()) ||
        (isVirtualCol != dest.getIsVirtualCol()) ||
        (isHiddenVirtualCol != dest.isHiddenVirtualCol())) {
      return false;
    }

    return true;
  }

  public boolean isSameColumnForRR(ColumnInfo other) {
    return checkEquals(tabAlias, other.tabAlias)
        && checkEquals(alias, other.alias)
        && checkEquals(internalName, other.internalName)
        && checkEquals(getType(), other.getType());
  }

  public String toMappingString(String tab, String col) {
    return tab + "." + col + " => {" + tabAlias + ", " + alias + ", "
        + internalName + ": " + getType() + "}";
  }

  public void setObjectinspector(ObjectInspector writableObjectInspector) {
    this.objectInspector = writableObjectInspector;
  }
}