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Java > Open Source Codes > org > apache > derby > iapi > sql > execute > TupleFilter


1 /*
2
3    Derby - Class org.apache.derby.iapi.sql.execute.TupleFilter
4
5    Licensed to the Apache Software Foundation (ASF) under one or more
6    contributor license agreements. See the NOTICE file distributed with
7    this work for additional information regarding copyright ownership.
8    The ASF licenses this file to you under the Apache License, Version 2.0
9    (the "License"); you may not use this file except in compliance with
10    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
22 package org.apache.derby.iapi.sql.execute;
23
24 import org.apache.derby.iapi.types.BooleanDataValue;
25
26 import org.apache.derby.iapi.error.StandardException;
27
28 /**
29  * A TupleFilter is used to qualify rows from a tuple stream.
30  *
31  * @author Rick
32  */
33 public interface TupleFilter
34 {
35     /**
36       * Initialize a Filter with a vector of parameters.
37       *
38       * @param parameters An ExecRow of parameter values
39       *
40       * @exception StandardException Thrown on error
41       */
42     public void init( ExecRow parameters )
43                 throws StandardException;
44
45     /**
46       * Pump a row through the Filter.
47       *
48       * @param currentRow Column values to plug into restriction
49       *
50       * @return True if the row qualifies. False otherwise.
51       *
52       * @exception StandardException Thrown on error
53       */
54     public BooleanDataValue execute( ExecRow currentRow )
55                 throws StandardException;
56 }
57
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