001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.filter;
019
020import java.util.Locale;
021import org.apache.hadoop.hbase.exceptions.DeserializationException;
022import org.apache.hadoop.hbase.util.Bytes;
023import org.apache.yetus.audience.InterfaceAudience;
024
025import org.apache.hbase.thirdparty.com.google.protobuf.InvalidProtocolBufferException;
026
027import org.apache.hadoop.hbase.shaded.protobuf.generated.ComparatorProtos;
028
029/**
030 * This comparator is for use with SingleColumnValueFilter, for filtering based on the value of a
031 * given column. Use it to test if a given substring appears in a cell value in the column. The
032 * comparison is case insensitive.
033 * <p>
034 * Only EQUAL or NOT_EQUAL tests are valid with this comparator.
035 * <p>
036 * For example:
037 * <p>
038 *
039 * <pre>
040 * SingleColumnValueFilter scvf =
041 *   new SingleColumnValueFilter("col", CompareOp.EQUAL, new SubstringComparator("substr"));
042 * </pre>
043 */
044@InterfaceAudience.Public
045@SuppressWarnings("ComparableType") // Should this move to Comparator usage?
046public class SubstringComparator extends ByteArrayComparable {
047
048  private String substr;
049
050  /**
051   * Constructor
052   * @param substr the substring
053   */
054  public SubstringComparator(String substr) {
055    super(Bytes.toBytes(substr.toLowerCase(Locale.ROOT)));
056    this.substr = substr.toLowerCase(Locale.ROOT);
057  }
058
059  @Override
060  public byte[] getValue() {
061    return Bytes.toBytes(substr);
062  }
063
064  @Override
065  public int compareTo(byte[] value, int offset, int length) {
066    return Bytes.toString(value, offset, length).toLowerCase(Locale.ROOT).contains(substr) ? 0 : 1;
067  }
068
069  /** Returns The comparator serialized using pb */
070  @Override
071  public byte[] toByteArray() {
072    ComparatorProtos.SubstringComparator.Builder builder =
073      ComparatorProtos.SubstringComparator.newBuilder();
074    builder.setSubstr(this.substr);
075    return builder.build().toByteArray();
076  }
077
078  /**
079   * Parse a serialized representation of {@link SubstringComparator}
080   * @param pbBytes A pb serialized {@link SubstringComparator} instance
081   * @return An instance of {@link SubstringComparator} made from <code>bytes</code>
082   * @throws DeserializationException if an error occurred
083   * @see #toByteArray
084   */
085  public static SubstringComparator parseFrom(final byte[] pbBytes)
086    throws DeserializationException {
087    ComparatorProtos.SubstringComparator proto;
088    try {
089      proto = ComparatorProtos.SubstringComparator.parseFrom(pbBytes);
090    } catch (InvalidProtocolBufferException e) {
091      throw new DeserializationException(e);
092    }
093    return new SubstringComparator(proto.getSubstr());
094  }
095
096  /**
097   * Returns true if and only if the fields of the comparator that are serialized are equal to the
098   * corresponding fields in other. Used for testing.
099   */
100  @Override
101  boolean areSerializedFieldsEqual(ByteArrayComparable other) {
102    if (other == this) {
103      return true;
104    }
105    if (!(other instanceof SubstringComparator)) {
106      return false;
107    }
108    SubstringComparator comparator = (SubstringComparator) other;
109    return super.areSerializedFieldsEqual(comparator) && this.substr.equals(comparator.substr);
110  }
111
112}