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
52 * {@link java.util.concurrent.Callable} interface. It also has a property
53 * {@link #repo} holding a reference to the git
54 * {@link org.eclipse.jgit.lib.Repository} this command should work with.
55 * <p>
56 * Finally this class stores a state telling whether it is allowed to call
57 * {@link #call()} on this instance. Instances of
58 * {@link org.eclipse.jgit.api.GitCommand} can only be used for one single
59 * successful call to {@link #call()}. Afterwards this instance may not be used
60 * anymore to set/modify any properties or to call {@link #call()} again. This
61 * is achieved by setting the {@link #callable} property to false after the
62 * successful execution of {@link #call()} and to check the state (by calling
63 * {@link #checkCallable()}) before setting of properties and inside
64 * {@link #call()}.
65 *
66 * @param <T>
67 * the return type which is expected from {@link #call()}
68 */
69 public abstract class GitCommand<T> implements Callable<T> {
70 /** The repository this command is working with */
71 final protected Repository repo;
72
73 /**
74 * a state which tells whether it is allowed to call {@link #call()} on this
75 * instance.
76 */
77 private AtomicBoolean callable = new AtomicBoolean(true);
78
79 /**
80 * Creates a new command which interacts with a single repository
81 *
82 * @param repo
83 * the {@link org.eclipse.jgit.lib.Repository} this command
84 * should interact with
85 */
86 protected GitCommand(Repository repo) {
87 this.repo = repo;
88 }
89
90 /**
91 * Get repository this command is working on
92 *
93 * @return the {@link org.eclipse.jgit.lib.Repository} this command is
94 * interacting with
95 */
96 public Repository getRepository() {
97 return repo;
98 }
99
100 /**
101 * Set's the state which tells whether it is allowed to call {@link #call()}
102 * on this instance. {@link #checkCallable()} will throw an exception when
103 * called and this property is set to {@code false}
104 *
105 * @param callable
106 * if <code>true</code> it is allowed to call {@link #call()} on
107 * this instance.
108 */
109 protected void setCallable(boolean callable) {
110 this.callable.set(callable);
111 }
112
113 /**
114 * Checks that the property {@link #callable} is {@code true}. If not then
115 * an {@link java.lang.IllegalStateException} is thrown
116 *
117 * @throws java.lang.IllegalStateException
118 * when this method is called and the property {@link #callable}
119 * is {@code false}
120 */
121 protected void checkCallable() {
122 if (!callable.get())
123 throw new IllegalStateException(MessageFormat.format(
124 JGitText.get().commandWasCalledInTheWrongState
125 , this.getClass().getName()));
126 }
127
128 /**
129 * {@inheritDoc}
130 * <p>
131 * Execute the command
132 */
133 @Override
134 public abstract T call() throws GitAPIException;
135 }