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Java > Open Source Codes > proguard > io > FilteredDataEntryReader


1 /*
2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
3  * of Java bytecode.
4  *
5  * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu)
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  *
12  * This program is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with this program; if not, write to the Free Software Foundation, Inc.,
19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 package proguard.io;
22
23 import java.io.*;
24
25
26 /**
27  * This DataEntryReader delegates to one of two other DataEntryReader instances,
28  * depending on whether the data entry passes through a given data entry filter
29  * or not.
30  *
31  * @author Eric Lafortune
32  */
33 public class FilteredDataEntryReader implements DataEntryReader
34 {
35     private DataEntryFilter dataEntryFilter;
36     private DataEntryReader acceptedDataEntryReader;
37     private DataEntryReader rejectedDataEntryReader;
38
39
40     /**
41      * Creates a new FilteredDataEntryReader with only a reader for accepted
42      * data entries.
43      * @param dataEntryFilter the data entry filter.
44      * @param acceptedDataEntryReader the DataEntryReader to which the reading
45      * will be delegated if the filter accepts
46      * the data entry. May be <code>null</code>.
47      */
48     public FilteredDataEntryReader(DataEntryFilter dataEntryFilter,
49                                    DataEntryReader acceptedDataEntryReader)
50     {
51         this(dataEntryFilter, acceptedDataEntryReader, null);
52     }
53
54
55     /**
56      * Creates a new FilteredDataEntryReader.
57      * @param dataEntryFilter the data entry filter.
58      * @param acceptedDataEntryReader the DataEntryReader to which the reading
59      * will be delegated if the filter accepts
60      * the data entry. May be <code>null</code>.
61      * @param rejectedDataEntryReader the DataEntryReader to which the reading
62      * will be delegated if the filter does not
63      * accept the data entry. May be
64      * <code>null</code>.
65      */
66     public FilteredDataEntryReader(DataEntryFilter dataEntryFilter,
67                                    DataEntryReader acceptedDataEntryReader,
68                                    DataEntryReader rejectedDataEntryReader)
69     {
70         this.dataEntryFilter = dataEntryFilter;
71         this.acceptedDataEntryReader = acceptedDataEntryReader;
72         this.rejectedDataEntryReader = rejectedDataEntryReader;
73     }
74
75
76     // Implementations for DataEntryReader.
77
78     public void read(DataEntry dataEntry)
79     throws IOException
80     {
81         DataEntryReader dataEntryReader = dataEntryFilter.accepts(dataEntry) ?
82             acceptedDataEntryReader :
83             rejectedDataEntryReader;
84
85         if (dataEntryReader != null)
86         {
87             dataEntryReader.read(dataEntry);
88         }
89     }
90 }
91
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