/**
    *
    * 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.filter;
  
  import java.io.IOException;
  import java.util.ArrayList;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
  
  import com.google.protobuf.InvalidProtocolBufferException;
  
  /**
   * This filter is used to filter based on the column qualifier. It takes an
   * operator (equal, greater, not equal, etc) and a byte [] comparator for the
   * column qualifier portion of a key.
   * <p>
   * This filter can be wrapped with {@link WhileMatchFilter} and {@link SkipFilter}
   * to add more control.
   * <p>
   * Multiple filters can be combined using {@link FilterList}.
   * <p>
   * If an already known column qualifier is looked for, use 
   * {@link org.apache.hadoop.hbase.client.Get#addColumn}
   * directly rather than a filter.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class QualifierFilter extends CompareFilter {
  
    /**
     * Constructor.
     * @param op the compare op for column qualifier matching
     * @param qualifierComparator the comparator for column qualifier matching
     */
    public QualifierFilter(final CompareOp op,
        final ByteArrayComparable qualifierComparator) {
      super(op, qualifierComparator);
    }
  
    @Override
    public ReturnCode filterKeyValue(Cell v) {
      if (doCompare(this.compareOp, this.comparator, v.getQualifierArray(),
          v.getQualifierOffset(), v.getQualifierLength())) {
        return ReturnCode.SKIP;
      }
      return ReturnCode.INCLUDE;
    }
  
    public static Filter createFilterFromArguments(ArrayList<byte []> filterArguments) {
      ArrayList<?> arguments = CompareFilter.extractArguments(filterArguments);
      CompareOp compareOp = (CompareOp)arguments.get(0);
      ByteArrayComparable comparator = (ByteArrayComparable)arguments.get(1);
      return new QualifierFilter(compareOp, comparator);
    }
  
    /**
     * @return The filter serialized using pb
     */
    @Override
    public byte [] toByteArray() {
      FilterProtos.QualifierFilter.Builder builder =
        FilterProtos.QualifierFilter.newBuilder();
      builder.setCompareFilter(super.convert());
      return builder.build().toByteArray();
    }
  
    /**
     * @param pbBytes A pb serialized {@link QualifierFilter} instance
     * @return An instance of {@link QualifierFilter} made from <code>bytes</code>
     * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
     * @see #toByteArray
     */
    public static QualifierFilter parseFrom(final byte [] pbBytes)
    throws DeserializationException {
      FilterProtos.QualifierFilter proto;
      try {
        proto = FilterProtos.QualifierFilter.parseFrom(pbBytes);
     } catch (InvalidProtocolBufferException e) {
       throw new DeserializationException(e);
     }
     final CompareOp valueCompareOp =
       CompareOp.valueOf(proto.getCompareFilter().getCompareOp().name());
     ByteArrayComparable valueComparator = null;
     try {
       if (proto.getCompareFilter().hasComparator()) {
         valueComparator = ProtobufUtil.toComparator(proto.getCompareFilter().getComparator());
       }
     } catch (IOException ioe) {
       throw new DeserializationException(ioe);
     }
     return new QualifierFilter(valueCompareOp,valueComparator);
   }
 
   /**
    * @param other
    * @return true if and only if the fields of the filter that are serialized
    * are equal to the corresponding fields in other.  Used for testing.
    */
   @Override
   boolean areSerializedFieldsEqual(Filter o) {
     if (o == this) return true;
     if (!(o instanceof QualifierFilter)) return false;
 
     return super.areSerializedFieldsEqual(o);
   }
 
   @Override
   public boolean equals(Object obj) {
     return obj instanceof Filter && areSerializedFieldsEqual((Filter) obj);
   }
 
   @Override
   public int hashCode() {
     return super.hashCode();
   }
 }