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Java > Open Source Codes > proguard > io > CascadingDataEntryWriter


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 proguard.util.*;
24
25 import java.io.*;
26
27 /**
28  * This DataEntryWriter delegates to a given DataEntryWriter, or failing that,
29  * to another given DataEntryWriter.
30  *
31  * @author Eric Lafortune
32  */

33 public class CascadingDataEntryWriter implements DataEntryWriter
34 {
35     private DataEntryWriter dataEntryWriter1;
36     private DataEntryWriter dataEntryWriter2;
37
38
39     /**
40      * Creates a new CascadingDataEntryWriter.
41      * @param dataEntryWriter1 the DataEntryWriter to which the writing will be
42      * delegated first.
43      * @param dataEntryWriter2 the DataEntryWriter to which the writing will be
44      * delegated, if the first one can't provide an
45      * output stream.
46      */

47     public CascadingDataEntryWriter(DataEntryWriter dataEntryWriter1,
48                                     DataEntryWriter dataEntryWriter2)
49     {
50         this.dataEntryWriter1 = dataEntryWriter1;
51         this.dataEntryWriter2 = dataEntryWriter2;
52     }
53
54
55     // Implementations for DataEntryWriter.
56

57     public OutputStream getOutputStream(DataEntry dataEntry) throws IOException
58     {
59         return getOutputStream(dataEntry, null);
60     }
61
62
63     public OutputStream getOutputStream(DataEntry dataEntry,
64                                         Finisher finisher) throws IOException
65     {
66         // Try to get an output stream from the first data entry writer.
67
OutputStream outputStream =
68             dataEntryWriter1.getOutputStream(dataEntry, finisher);
69
70         // Return it, if it's not null. Otherwise try to get an output stream
71
// from the second data entry writer.
72
return outputStream != null ?
73             outputStream :
74             dataEntryWriter2.getOutputStream(dataEntry, finisher);
75     }
76
77
78     public void close() throws IOException
79     {
80         dataEntryWriter1.close();
81         dataEntryWriter2.close();
82
83         dataEntryWriter1 = null;
84         dataEntryWriter2 = null;
85     }
86 }
87
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