1 /*
2 * Copyright (C) 2016, Christian Halstrick <christian.halstrick@sap.com>
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43 package org.eclipse.jgit.attributes;
44
45 import java.io.IOException;
46 import java.io.InputStream;
47 import java.io.OutputStream;
48
49 /**
50 * An abstraction for JGit's builtin implementations for hooks and filters.
51 * Instead of spawning an external processes to start a filter/hook and to pump
52 * data from/to stdin/stdout these builtin commmands may be used. They are
53 * constructed by {@link org.eclipse.jgit.attributes.FilterCommandFactory}.
54 *
55 * @since 4.6
56 */
57 public abstract class FilterCommand {
58 /**
59 * The {@link InputStream} this command should read from
60 */
61 protected InputStream in;
62
63 /**
64 * The {@link OutputStream} this command should write to
65 */
66 protected OutputStream out;
67
68 /**
69 * Constructor for FilterCommand
70 * <p>
71 * FilterCommand implementors are required to manage the in and out streams
72 * (close on success and/or exception).
73 *
74 * @param in
75 * The {@link java.io.InputStream} this command should read from
76 * @param out
77 * The {@link java.io.OutputStream} this command should write to
78 */
79 public FilterCommand(InputStream in, OutputStream out) {
80 this.in = in;
81 this.out = out;
82 }
83
84 /**
85 * Execute the command. The command is supposed to read data from
86 * {@link #in} and to write the result to {@link #out}. It returns the
87 * number of bytes it read from {@link #in}. It should be called in a loop
88 * until it returns -1 signaling that the {@link java.io.InputStream} is
89 * completely processed.
90 * <p>
91 * On successful completion (return -1) or on Exception, the streams
92 * {@link #in} and {@link #out} are closed by the implementation.
93 *
94 * @return the number of bytes read from the {@link java.io.InputStream} or
95 * -1. -1 means that the {@link java.io.InputStream} is completely
96 * processed.
97 * @throws java.io.IOException
98 * when {@link java.io.IOException} occured while reading from
99 * {@link #in} or writing to {@link #out}
100 */
101 public abstract int run() throws IOException;
102 }