1 /*
2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
3  *             of Java bytecode.
4  *
5  * Copyright (c) 2002-2014 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  * This DataEntryWriter delegates to a given DataEntryWriter, or failing that,
27  * to another given DataEntryWriter.
28  *
29  * @author Eric Lafortune
30  */
31 public class CascadingDataEntryWriter implements DataEntryWriter
32 {
33     private DataEntryWriter dataEntryWriter1;
34     private DataEntryWriter dataEntryWriter2;
35 
36 
37     /**
38      * Creates a new CascadingDataEntryWriter.
39      * @param dataEntryWriter1 the DataEntryWriter to which the writing will be
40      *                         delegated first.
41      * @param dataEntryWriter2 the DataEntryWriter to which the writing will be
42      *                         delegated, if the first one can't provide an
43      *                         output stream.
44      */
CascadingDataEntryWriter(DataEntryWriter dataEntryWriter1, DataEntryWriter dataEntryWriter2)45     public CascadingDataEntryWriter(DataEntryWriter dataEntryWriter1,
46                                     DataEntryWriter dataEntryWriter2)
47     {
48         this.dataEntryWriter1 = dataEntryWriter1;
49         this.dataEntryWriter2 = dataEntryWriter2;
50     }
51 
52 
53     // Implementations for DataEntryWriter.
54 
55 
createDirectory(DataEntry dataEntry)56     public boolean createDirectory(DataEntry dataEntry) throws IOException
57     {
58         // Try to create a directory with the first data entry writer, or
59         // otherwise with the second data entry writer.
60         return dataEntryWriter1.createDirectory(dataEntry) ||
61                dataEntryWriter2.createDirectory(dataEntry);
62     }
63 
64 
getOutputStream(DataEntry dataEntry)65     public OutputStream getOutputStream(DataEntry dataEntry) throws IOException
66     {
67         return getOutputStream(dataEntry,  null);
68     }
69 
70 
getOutputStream(DataEntry dataEntry, Finisher finisher)71     public OutputStream getOutputStream(DataEntry dataEntry,
72                                         Finisher  finisher) throws IOException
73     {
74         // Try to get an output stream from the first data entry writer.
75         OutputStream outputStream =
76             dataEntryWriter1.getOutputStream(dataEntry, finisher);
77 
78         // Return it, if it's not null. Otherwise try to get an output stream
79         // from the second data entry writer.
80         return outputStream != null ?
81             outputStream :
82             dataEntryWriter2.getOutputStream(dataEntry, finisher);
83     }
84 
85 
close()86     public void close() throws IOException
87     {
88         dataEntryWriter1.close();
89         dataEntryWriter2.close();
90 
91         dataEntryWriter1 = null;
92         dataEntryWriter2 = null;
93     }
94 }
95