1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2009 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 */
21package proguard.io;
22
23import java.io.*;
24
25/**
26 * This DataEntryWriter delegates to one of two other DataEntryWriter instances,
27 * depending on whether the data entry passes through a given data entry filter
28 * or not.
29 *
30 * @author Eric Lafortune
31 */
32public class FilteredDataEntryWriter implements DataEntryWriter
33{
34    private final DataEntryFilter dataEntryFilter;
35    private DataEntryWriter acceptedDataEntryWriter;
36    private DataEntryWriter rejectedDataEntryWriter;
37
38
39    /**
40     * Creates a new FilteredDataEntryWriter with only a writer for accepted
41     * data entries.
42     * @param dataEntryFilter         the data entry filter.
43     * @param acceptedDataEntryWriter the DataEntryWriter to which the writing
44     *                                will be delegated if the filter accepts
45     *                                the data entry. May be <code>null</code>.
46     */
47    public FilteredDataEntryWriter(DataEntryFilter dataEntryFilter,
48                                   DataEntryWriter acceptedDataEntryWriter)
49    {
50        this(dataEntryFilter, acceptedDataEntryWriter, null);
51    }
52
53
54    /**
55     * Creates a new FilteredDataEntryWriter.
56     * @param dataEntryFilter         the data entry filter.
57     * @param acceptedDataEntryWriter the DataEntryWriter to which the writing
58     *                                will be delegated if the filter accepts
59     *                                the data entry. May be <code>null</code>.
60     * @param rejectedDataEntryWriter the DataEntryWriter to which the writing
61     *                                will be delegated if the filter does not
62     *                                accept the data entry. May be
63     *                                <code>null</code>.
64     */
65    public FilteredDataEntryWriter(DataEntryFilter dataEntryFilter,
66                                   DataEntryWriter acceptedDataEntryWriter,
67                                   DataEntryWriter rejectedDataEntryWriter)
68    {
69        this.dataEntryFilter         = dataEntryFilter;
70        this.acceptedDataEntryWriter = acceptedDataEntryWriter;
71        this.rejectedDataEntryWriter = rejectedDataEntryWriter;
72    }
73
74
75    // Implementations for DataEntryWriter.
76
77    public boolean createDirectory(DataEntry dataEntry) throws IOException
78    {
79        // Get the right data entry writer.
80        DataEntryWriter dataEntryWriter = dataEntryFilter.accepts(dataEntry) ?
81            acceptedDataEntryWriter :
82            rejectedDataEntryWriter;
83
84        // Delegate to it, if it's not null.
85        return dataEntryWriter != null &&
86               dataEntryWriter.createDirectory(dataEntry);
87    }
88
89
90    public OutputStream getOutputStream(DataEntry dataEntry) throws IOException
91    {
92        return getOutputStream(dataEntry,  null);
93    }
94
95
96    public OutputStream getOutputStream(DataEntry dataEntry,
97                                        Finisher  finisher) throws IOException
98    {
99        // Get the right data entry writer.
100        DataEntryWriter dataEntryWriter = dataEntryFilter.accepts(dataEntry) ?
101            acceptedDataEntryWriter :
102            rejectedDataEntryWriter;
103
104        // Delegate to it, if it's not null.
105        return dataEntryWriter != null ?
106            dataEntryWriter.getOutputStream(dataEntry, finisher) :
107            null;
108    }
109
110
111    public void close() throws IOException
112    {
113        if (acceptedDataEntryWriter != null)
114        {
115            acceptedDataEntryWriter.close();
116            acceptedDataEntryWriter = null;
117        }
118
119        if (rejectedDataEntryWriter != null)
120        {
121            rejectedDataEntryWriter.close();
122            rejectedDataEntryWriter = null;
123        }
124    }
125}
126