ColumnQualifier.java

/**
 * Copyright 2011 The Apache Software Foundation
 *
 * 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.hbase.index;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.hbase.index.ValuePartition.PartitionType;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.WritableComparable;

/**
 * A ColumnQualifier contains information about column family name,qualifier and maximum value
 * length used in index specification. maValueLength is used to make sure the common pattern for all
 * the rowkeys in the index table. ColumnQualifier is used as input for index specification to
 * specify column family and column qualifier on which we are going to do indexing.
 */
public class ColumnQualifier implements WritableComparable<ColumnQualifier> {

  private byte[] cfBytes;

  private byte[] qualifierBytes;

  private int maxValueLength;

  private ValuePartition valuePartition = null;

  private ValueType type;

  public ColumnQualifier() {
    // Dummy constructor which is needed for the readFields
  }

  public ColumnQualifier(String cf, String qualifier) {
    this(Bytes.toBytes(cf), Bytes.toBytes(qualifier));
  }

  public ColumnQualifier(byte[] cf, byte[] qualifier) {
    this(cf, qualifier, ValueType.String, 0, null);
  }

  public ColumnQualifier(String cf, String qualifier, ValueType type, int maxValueLength) {
    this(Bytes.toBytes(cf), Bytes.toBytes(qualifier), type, maxValueLength, null);
  }

  public ColumnQualifier(String cf, String qualifier, ValueType type, int maxValueLength,
      ValuePartition vp) {
    this(Bytes.toBytes(cf), Bytes.toBytes(qualifier), type, maxValueLength, vp);
  }

  public ColumnQualifier(byte[] cf, byte[] qualifier, ValueType type, int maxValueLength,
      ValuePartition vp) {
    this.cfBytes = cf;
    this.qualifierBytes = qualifier;
    this.type = type;
    this.maxValueLength = maxValueLength;
    this.valuePartition = vp;
  }

  /**
   * @return Column Family as string
   */
  public String getColumnFamilyString() {
    return Bytes.toString(this.cfBytes);
  }

  /**
   * @return Column qualifier as string
   */
  public String getQualifierString() {
    return Bytes.toString(this.qualifierBytes);
  }

  /**
   * @return Column family as byte array
   */
  public byte[] getColumnFamily() {
    return this.cfBytes;
  }

  /**
   * @return Column qualifier as byte array
   */
  public byte[] getQualifier() {
    return this.qualifierBytes;
  }

  public ValuePartition getValuePartition() {
    return valuePartition;
  }

  /**
   * @param DataInput Stream
   * @throws IOException
   */
  public void readFields(DataInput in) throws IOException {
    this.cfBytes = Bytes.readByteArray(in);
    this.qualifierBytes = Bytes.readByteArray(in);
    this.type = ValueType.valueOf(Bytes.toString(Bytes.readByteArray(in)));
    this.maxValueLength = in.readInt();
    PartitionType p = PartitionType.valueOf(in.readUTF());
    if (p.equals(PartitionType.SEPARATOR)) {
      valuePartition = new SeparatorPartition();
    } else if (p.equals(PartitionType.SPATIAL)) {
      valuePartition = new SpatialPartition();
    }
    if (valuePartition != null) {
      valuePartition.readFields(in);
    }
  }

  /**
   * @param DataOutput stream
   * @throws IOException
   */
  public void write(DataOutput out) throws IOException {
    Bytes.writeByteArray(out, this.cfBytes);
    Bytes.writeByteArray(out, this.qualifierBytes);
    Bytes.writeByteArray(out, Bytes.toBytes(this.type.name()));
    out.writeInt(maxValueLength);
    if (valuePartition == null) {
      out.writeUTF(PartitionType.NONE.name());
    } else {
      out.writeUTF(valuePartition.getPartitionType().name());
      valuePartition.write(out);
    }
  }

  /**
   * @param ColumnQualifier with whom to compare
   * @return return true if both objects are equal otherwise false
   */
  @Override
  public boolean equals(Object cq) {
    if (this == cq) {
      return true;
    }
    if (false == (cq instanceof ColumnQualifier)) {
      return false;
    }
    return this.compareTo((ColumnQualifier) cq) == 0;
  }

  /**
   * return hashcode of object
   */
  public int hashCode() {
    int result = Bytes.hashCode(this.cfBytes);
    result ^= Bytes.hashCode(this.qualifierBytes);
    result ^= this.maxValueLength;
    if (valuePartition != null) result ^= valuePartition.hashCode();
    return result;
  }

  /**
   * @param IndexSpecification
   * @return int
   */
  @Override
  public int compareTo(ColumnQualifier cq) {
    int diff = 0;
    diff = Bytes.compareTo(this.cfBytes, cq.cfBytes);
    if (0 == diff) {
      diff = Bytes.compareTo(this.qualifierBytes, cq.qualifierBytes);
      if (0 == diff) {
        if (valuePartition != null && cq.valuePartition != null) {
          return valuePartition.compareTo(cq.valuePartition);
        } else if (valuePartition == null && cq.valuePartition == null) {
          return 0;
        } else {
          return 1;
        }
      }
    }
    return diff;
  }

  public int getMaxValueLength() {
    return this.maxValueLength;
  }

  public ValueType getType() {
    return this.type;
  }

  public enum ValueType {
    String, Int, Float, Long, Double, Short, Byte, Char
  };

  // TODO - Include valuePartition also into this
  public String toString() {
    return "CF : " + getColumnFamilyString() + ",Qualifier : " + getQualifierString();
  }
}