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1   /**
2    * Copyright 2010 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  
21  package org.apache.hadoop.hbase.filter;
22  
23  import org.apache.hadoop.hbase.KeyValue;
24  import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp;
25  
26  /**
27   * A {@link Filter} that checks a single column value, but does not emit the
28   * tested column. This will enable a performance boost over
29   * {@link SingleColumnValueFilter}, if the tested column value is not actually
30   * needed as input (besides for the filtering itself).
31   */
32  public class SingleColumnValueExcludeFilter extends SingleColumnValueFilter {
33  
34    /**
35     * Writable constructor, do not use.
36     */
37    public SingleColumnValueExcludeFilter() {
38      super();
39    }
40  
41    /**
42     * Constructor for binary compare of the value of a single column. If the
43     * column is found and the condition passes, all columns of the row will be
44     * emitted; except for the tested column value. If the column is not found or
45     * the condition fails, the row will not be emitted.
46     *
47     * @param family name of column family
48     * @param qualifier name of column qualifier
49     * @param compareOp operator
50     * @param value value to compare column values against
51     */
52    public SingleColumnValueExcludeFilter(byte[] family, byte[] qualifier,
53        CompareOp compareOp, byte[] value) {
54      super(family, qualifier, compareOp, value);
55    }
56  
57    /**
58     * Constructor for binary compare of the value of a single column. If the
59     * column is found and the condition passes, all columns of the row will be
60     * emitted; except for the tested column value. If the condition fails, the
61     * row will not be emitted.
62     * <p>
63     * Use the filterIfColumnMissing flag to set whether the rest of the columns
64     * in a row will be emitted if the specified column to check is not found in
65     * the row.
66     *
67     * @param family name of column family
68     * @param qualifier name of column qualifier
69     * @param compareOp operator
70     * @param comparator Comparator to use.
71     */
72    public SingleColumnValueExcludeFilter(byte[] family, byte[] qualifier,
73        CompareOp compareOp, WritableByteArrayComparable comparator) {
74      super(family, qualifier, compareOp, comparator);
75    }
76  
77    public ReturnCode filterKeyValue(KeyValue keyValue) {
78      ReturnCode superRetCode = super.filterKeyValue(keyValue);
79      if (superRetCode == ReturnCode.INCLUDE) {
80        // If the current column is actually the tested column,
81        // we will skip it instead.
82        if (keyValue.matchingColumn(this.columnFamily, this.columnQualifier)) {
83          return ReturnCode.SKIP;
84        }
85      }
86      return superRetCode;
87    }
88  }