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comparison src/org/tmatesoft/hg/internal/FilterByteChannel.java @ 115:c0cc2535462c

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Introduced channels to pipeline (and easily filter) data streams
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Thu, 03 Feb 2011 23:32:08 +0100
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children 7567f4a42fe5
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114:46291ec605a0 115:c0cc2535462c
1 /*
2 * Copyright (c) 2011 TMate Software Ltd
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * For information on how to redistribute this software under
14 * the terms of a license other than GNU General Public License
15 * contact TMate Software at support@svnkit.com
16 */
17 package org.tmatesoft.hg.internal;
18
19 import java.nio.ByteBuffer;
20 import java.util.Collection;
21
22 import org.tmatesoft.hg.util.ByteChannel;
23
24 /**
25 *
26 * @author Artem Tikhomirov
27 * @author TMate Software Ltd.
28 */
29 public class FilterByteChannel implements ByteChannel {
30 private final Filter[] filters;
31 private final ByteChannel delegate;
32
33 public FilterByteChannel(ByteChannel delegateChannel, Collection<Filter> filtersToApply) {
34 if (delegateChannel == null || filtersToApply == null) {
35 throw new IllegalArgumentException();
36 }
37 delegate = delegateChannel;
38 filters = filtersToApply.toArray(new Filter[filtersToApply.size()]);
39 }
40
41 public int write(ByteBuffer buffer) throws Exception {
42 final int srcPos = buffer.position();
43 ByteBuffer processed = buffer;
44 for (Filter f : filters) {
45 // each next filter consumes not more than previous
46 // hence total consumed equals position shift in the original buffer
47 processed = f.filter(processed);
48 }
49 delegate.write(processed);
50 return buffer.position() - srcPos; // consumed as much from original buffer
51 }
52
53 }