001/*
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019
020package org.apache.hadoop.hbase.filter;
021
022import java.io.IOException;
023import java.util.ArrayList;
024
025import org.apache.hadoop.hbase.ByteBufferExtendedCell;
026import org.apache.hadoop.hbase.Cell;
027import org.apache.hadoop.hbase.PrivateCellUtil;
028import org.apache.yetus.audience.InterfaceAudience;
029import org.apache.hadoop.hbase.exceptions.DeserializationException;
030import org.apache.hadoop.hbase.shaded.protobuf.generated.FilterProtos;
031import org.apache.hadoop.hbase.util.ByteBufferUtils;
032import org.apache.hadoop.hbase.util.Bytes;
033
034import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
035import org.apache.hbase.thirdparty.com.google.protobuf.InvalidProtocolBufferException;
036import org.apache.hbase.thirdparty.com.google.protobuf.UnsafeByteOperations;
037
038/**
039 * This filter is used for selecting only those keys with columns that matches
040 * a particular prefix. For example, if prefix is 'an', it will pass keys with
041 * columns like 'and', 'anti' but not keys with columns like 'ball', 'act'.
042 */
043@InterfaceAudience.Public
044public class ColumnPrefixFilter extends FilterBase {
045  protected byte [] prefix = null;
046
047  public ColumnPrefixFilter(final byte [] prefix) {
048    this.prefix = prefix;
049  }
050
051  public byte[] getPrefix() {
052    return prefix;
053  }
054
055  @Override
056  public boolean filterRowKey(Cell cell) throws IOException {
057    // Impl in FilterBase might do unnecessary copy for Off heap backed Cells.
058    return false;
059  }
060
061  @Deprecated
062  @Override
063  public ReturnCode filterKeyValue(final Cell c) {
064    return filterCell(c);
065  }
066
067  @Override
068  public ReturnCode filterCell(final Cell cell) {
069    if (this.prefix == null) {
070      return ReturnCode.INCLUDE;
071    } else {
072      return filterColumn(cell);
073    }
074  }
075
076  public ReturnCode filterColumn(Cell cell) {
077    int qualifierLength = cell.getQualifierLength();
078    if (qualifierLength < prefix.length) {
079      int cmp = compareQualifierPart(cell, qualifierLength, this.prefix);
080      if (cmp <= 0) {
081        return ReturnCode.SEEK_NEXT_USING_HINT;
082      } else {
083        return ReturnCode.NEXT_ROW;
084      }
085    } else {
086      int cmp = compareQualifierPart(cell, this.prefix.length, this.prefix);
087      if (cmp < 0) {
088        return ReturnCode.SEEK_NEXT_USING_HINT;
089      } else if (cmp > 0) {
090        return ReturnCode.NEXT_ROW;
091      } else {
092        return ReturnCode.INCLUDE;
093      }
094    }
095  }
096
097  private static int compareQualifierPart(Cell cell, int length, byte[] prefix) {
098    if (cell instanceof ByteBufferExtendedCell) {
099      return ByteBufferUtils.compareTo(((ByteBufferExtendedCell) cell).getQualifierByteBuffer(),
100          ((ByteBufferExtendedCell) cell).getQualifierPosition(), length, prefix, 0, length);
101    }
102    return Bytes.compareTo(cell.getQualifierArray(), cell.getQualifierOffset(), length, prefix, 0,
103        length);
104  }
105
106  public static Filter createFilterFromArguments(ArrayList<byte []> filterArguments) {
107    Preconditions.checkArgument(filterArguments.size() == 1,
108                                "Expected 1 but got: %s", filterArguments.size());
109    byte [] columnPrefix = ParseFilter.removeQuotesFromByteArray(filterArguments.get(0));
110    return new ColumnPrefixFilter(columnPrefix);
111  }
112
113  /**
114   * @return The filter serialized using pb
115   */
116  @Override
117  public byte [] toByteArray() {
118    FilterProtos.ColumnPrefixFilter.Builder builder =
119      FilterProtos.ColumnPrefixFilter.newBuilder();
120    if (this.prefix != null) builder.setPrefix(UnsafeByteOperations.unsafeWrap(this.prefix));
121    return builder.build().toByteArray();
122  }
123
124  /**
125   * @param pbBytes A pb serialized {@link ColumnPrefixFilter} instance
126   * @return An instance of {@link ColumnPrefixFilter} made from <code>bytes</code>
127   * @throws org.apache.hadoop.hbase.exceptions.DeserializationException
128   * @see #toByteArray
129   */
130  public static ColumnPrefixFilter parseFrom(final byte [] pbBytes)
131  throws DeserializationException {
132    FilterProtos.ColumnPrefixFilter proto;
133    try {
134      proto = FilterProtos.ColumnPrefixFilter.parseFrom(pbBytes);
135    } catch (InvalidProtocolBufferException e) {
136      throw new DeserializationException(e);
137    }
138    return new ColumnPrefixFilter(proto.getPrefix().toByteArray());
139  }
140
141  /**
142   * @param o the other filter to compare with
143   * @return true if and only if the fields of the filter that are serialized
144   * are equal to the corresponding fields in other.  Used for testing.
145   */
146  @Override
147  boolean areSerializedFieldsEqual(Filter o) {
148   if (o == this) return true;
149   if (!(o instanceof ColumnPrefixFilter)) return false;
150
151   ColumnPrefixFilter other = (ColumnPrefixFilter)o;
152    return Bytes.equals(this.getPrefix(), other.getPrefix());
153  }
154
155  @Override
156  public Cell getNextCellHint(Cell cell) {
157    return PrivateCellUtil.createFirstOnRowCol(cell, prefix, 0, prefix.length);
158  }
159
160  @Override
161  public String toString() {
162    return this.getClass().getSimpleName() + " " + Bytes.toStringBinary(this.prefix);
163  }
164
165  @Override
166  public boolean equals(Object obj) {
167    return obj instanceof Filter && areSerializedFieldsEqual((Filter) obj);
168  }
169
170  @Override
171  public int hashCode() {
172    return Bytes.hashCode(this.getPrefix());
173  }
174}