Assert.java revision 2840:84849fdb360b 
1/*
2 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package com.sun.tools.javac.util;
27
28import java.util.function.Supplier;
29
30/**
31 * Simple facility for unconditional assertions.
32 * The methods in this class are described in terms of equivalent assert
33 * statements, assuming that assertions have been enabled.
34 *
35 *  <p><b>This is NOT part of any supported API.
36 *  If you write code that depends on this, you do so at your own risk.
37 *  This code and its internal interfaces are subject to change or
38 *  deletion without notice.</b>
39 */
40public class Assert {
41    /** Equivalent to
42     *   assert cond;
43     */
44    public static void check(boolean cond) {
45        if (!cond)
46            error();
47    }
48
49    /** Equivalent to
50     *   assert (o == null);
51     */
52    public static void checkNull(Object o) {
53        if (o != null)
54            error();
55    }
56
57    /** Equivalent to
58     *   assert (t != null); return t;
59     */
60    public static <T> T checkNonNull(T t) {
61        if (t == null)
62            error();
63        return t;
64    }
65
66    /** Equivalent to
67     *   assert cond : value;
68     */
69    public static void check(boolean cond, int value) {
70        if (!cond)
71            error(String.valueOf(value));
72    }
73
74    /** Equivalent to
75     *   assert cond : value;
76     */
77    public static void check(boolean cond, long value) {
78        if (!cond)
79            error(String.valueOf(value));
80    }
81
82    /** Equivalent to
83     *   assert cond : value;
84     */
85    public static void check(boolean cond, Object value) {
86        if (!cond)
87            error(String.valueOf(value));
88    }
89
90    /** Equivalent to
91     *   assert cond : msg;
92     */
93    public static void check(boolean cond, String msg) {
94        if (!cond)
95            error(msg);
96    }
97
98    /** Equivalent to
99     *   assert cond : msg.get();
100     *  Note: message string is computed lazily.
101     */
102    public static void check(boolean cond, Supplier<String> msg) {
103        if (!cond)
104            error(msg.get());
105    }
106
107    /** Equivalent to
108     *   assert (o == null) : value;
109     */
110    public static void checkNull(Object o, Object value) {
111        if (o != null)
112            error(String.valueOf(value));
113    }
114
115    /** Equivalent to
116     *   assert (o == null) : msg;
117     */
118    public static void checkNull(Object o, String msg) {
119        if (o != null)
120            error(msg);
121    }
122
123    /** Equivalent to
124     *   assert (o == null) : msg.get();
125     *  Note: message string is computed lazily.
126     */
127    public static void checkNull(Object o, Supplier<String> msg) {
128        if (o != null)
129            error(msg.get());
130    }
131
132    /** Equivalent to
133     *   assert (o != null) : msg;
134     */
135    public static <T> T checkNonNull(T t, String msg) {
136        if (t == null)
137            error(msg);
138        return t;
139    }
140
141    /** Equivalent to
142     *   assert (o != null) : msg.get();
143     *  Note: message string is computed lazily.
144     */
145    public static <T> T checkNonNull(T t, Supplier<String> msg) {
146        if (t == null)
147            error(msg.get());
148        return t;
149    }
150
151    /** Equivalent to
152     *   assert false;
153     */
154    public static void error() {
155        throw new AssertionError();
156    }
157
158    /** Equivalent to
159     *   assert false : msg;
160     */
161    public static void error(String msg) {
162        throw new AssertionError(msg);
163    }
164
165    /** Prevent instantiation. */
166    private Assert() { }
167}
168