1 /*
2 * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com> and
3 * other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available under the
6 * terms of the Eclipse Distribution License v1.0 which accompanies this
7 * distribution, is reproduced below, and is available at
8 * 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 without
13 * modification, are permitted provided that the following conditions are met:
14 *
15 * - Redistributions of source code must retain the above copyright notice, this
16 * list of conditions and the following disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above copyright notice,
19 * this list of conditions and the following disclaimer in the documentation
20 * and/or other materials provided with the distribution.
21 *
22 * - Neither the name of the Eclipse Foundation, Inc. nor the names of its
23 * contributors may be used to endorse or promote products derived from this
24 * software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
27 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
30 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38 package org.eclipse.jgit.api;
39
40 import java.text.MessageFormat;
41 import java.util.concurrent.Callable;
42 import java.util.concurrent.atomic.AtomicBoolean;
43
44 import org.eclipse.jgit.api.errors.GitAPIException;
45 import org.eclipse.jgit.internal.JGitText;
46 import org.eclipse.jgit.lib.Repository;
47
48 /**
49 * Common superclass of all commands in the package {@code org.eclipse.jgit.api}
50 * <p>
51 * This class ensures that all commands fulfill the {@link Callable} interface.
52 * It also has a property {@link #repo} holding a reference to the git
53 * {@link Repository} this command should work with.
54 * <p>
55 * Finally this class stores a state telling whether it is allowed to call
56 * {@link #call()} on this instance. Instances of {@link GitCommand} can only be
57 * used for one single successful call to {@link #call()}. Afterwards this
58 * instance may not be used anymore to set/modify any properties or to call
59 * {@link #call()} again. This is achieved by setting the {@link #callable}
60 * property to false after the successful execution of {@link #call()} and to
61 * check the state (by calling {@link #checkCallable()}) before setting of
62 * properties and inside {@link #call()}.
63 *
64 * @param <T>
65 * the return type which is expected from {@link #call()}
66 */
67 public abstract class GitCommand<T> implements Callable<T> {
68 /** The repository this command is working with */
69 final protected Repository repo;
70
71 /**
72 * a state which tells whether it is allowed to call {@link #call()} on this
73 * instance.
74 */
75 private AtomicBoolean callable = new AtomicBoolean(true);
76
77 /**
78 * Creates a new command which interacts with a single repository
79 *
80 * @param repo
81 * the {@link Repository} this command should interact with
82 */
83 protected GitCommand(Repository repo) {
84 this.repo = repo;
85 }
86
87 /**
88 * @return the {@link Repository} this command is interacting with
89 */
90 public Repository getRepository() {
91 return repo;
92 }
93
94 /**
95 * Set's the state which tells whether it is allowed to call {@link #call()}
96 * on this instance. {@link #checkCallable()} will throw an exception when
97 * called and this property is set to {@code false}
98 *
99 * @param callable
100 * if <code>true</code> it is allowed to call {@link #call()} on
101 * this instance.
102 */
103 protected void setCallable(boolean callable) {
104 this.callable.set(callable);
105 }
106
107 /**
108 * Checks that the property {@link #callable} is {@code true}. If not then
109 * an {@link IllegalStateException} is thrown
110 *
111 * @throws IllegalStateException
112 * when this method is called and the property {@link #callable}
113 * is {@code false}
114 */
115 protected void checkCallable() {
116 if (!callable.get())
117 throw new IllegalStateException(MessageFormat.format(
118 JGitText.get().commandWasCalledInTheWrongState
119 , this.getClass().getName()));
120 }
121
122 /**
123 * Executes the command
124 *
125 * @return T a result. Each command has its own return type
126 * @throws GitAPIException
127 * or subclass thereof when an error occurs
128 */
129 @Override
130 public abstract T call() throws GitAPIException;
131 }