/*
    *
    * 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.util.ArrayList;
  
  import org.apache.hadoop.hbase.util.ByteStringer;
  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.KeyValueUtil;
  import org.apache.hadoop.hbase.exceptions.DeserializationException;
  import org.apache.hadoop.hbase.protobuf.generated.FilterProtos;
  import org.apache.hadoop.hbase.util.Bytes;
  
  import com.google.common.base.Preconditions;
  import com.google.protobuf.InvalidProtocolBufferException;
  
  /**
   * This filter is used for selecting only those keys with columns that matches
   * a particular prefix. For example, if prefix is 'an', it will pass keys with
   * columns like 'and', 'anti' but not keys with columns like 'ball', 'act'.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class ColumnPrefixFilter extends FilterBase {
    protected byte [] prefix = null;
  
    public ColumnPrefixFilter(final byte [] prefix) {
      this.prefix = prefix;
    }
  
    public byte[] getPrefix() {
      return prefix;
    }
  
    @Override
    public ReturnCode filterKeyValue(Cell kv) {
      if (this.prefix == null || kv.getQualifierArray() == null) {
        return ReturnCode.INCLUDE;
      } else {
        return filterColumn(kv.getQualifierArray(), kv.getQualifierOffset(), kv.getQualifierLength());
      }
    }
  
    // Override here explicitly as the method in super class FilterBase might do a KeyValue recreate.
    // See HBASE-12068
    @Override
    public Cell transformCell(Cell v) {
      return v;
    }
  
    public ReturnCode filterColumn(byte[] buffer, int qualifierOffset, int qualifierLength) {
      if (qualifierLength < prefix.length) {
        int cmp = Bytes.compareTo(buffer, qualifierOffset, qualifierLength, this.prefix, 0,
            qualifierLength);
        if (cmp <= 0) {
          return ReturnCode.SEEK_NEXT_USING_HINT;
        } else {
          return ReturnCode.NEXT_ROW;
        }
      } else {
        int cmp = Bytes.compareTo(buffer, qualifierOffset, this.prefix.length, this.prefix, 0,
            this.prefix.length);
        if (cmp < 0) {
          return ReturnCode.SEEK_NEXT_USING_HINT;
        } else if (cmp > 0) {
          return ReturnCode.NEXT_ROW;
        } else {
          return ReturnCode.INCLUDE;
        }
      }
    }
  
    public static Filter createFilterFromArguments(ArrayList<byte []> filterArguments) {
      Preconditions.checkArgument(filterArguments.size() == 1,
                                  "Expected 1 but got: %s", filterArguments.size());
      byte [] columnPrefix = ParseFilter.removeQuotesFromByteArray(filterArguments.get(0));
      return new ColumnPrefixFilter(columnPrefix);
    }
  
    /**
    * @return The filter serialized using pb
    */
   public byte [] toByteArray() {
     FilterProtos.ColumnPrefixFilter.Builder builder =
       FilterProtos.ColumnPrefixFilter.newBuilder();
     if (this.prefix != null) builder.setPrefix(ByteStringer.wrap(this.prefix));
     return builder.build().toByteArray();
   }
 
   /**
    * @param pbBytes A pb serialized {@link ColumnPrefixFilter} instance
    * @return An instance of {@link ColumnPrefixFilter} made from <code>bytes</code>
    * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
    * @see #toByteArray
    */
   public static ColumnPrefixFilter parseFrom(final byte [] pbBytes)
   throws DeserializationException {
     FilterProtos.ColumnPrefixFilter proto;
     try {
       proto = FilterProtos.ColumnPrefixFilter.parseFrom(pbBytes);
     } catch (InvalidProtocolBufferException e) {
       throw new DeserializationException(e);
     }
     return new ColumnPrefixFilter(proto.getPrefix().toByteArray());
   }
 
   /**
    * @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.
    */
   boolean areSerializedFieldsEqual(Filter o) {
    if (o == this) return true;
    if (!(o instanceof ColumnPrefixFilter)) return false;
 
    ColumnPrefixFilter other = (ColumnPrefixFilter)o;
     return Bytes.equals(this.getPrefix(), other.getPrefix());
   }
 
   @Override
   public Cell getNextCellHint(Cell kv) {
     return KeyValueUtil.createFirstOnRow(
         kv.getRowArray(), kv.getRowOffset(), kv.getRowLength(), kv.getFamilyArray(),
         kv.getFamilyOffset(), kv.getFamilyLength(), prefix, 0, prefix.length);
   }
 
   @Override
   public String toString() {
     return this.getClass().getSimpleName() + " " + Bytes.toStringBinary(this.prefix);
   }
 }