1 /*
   2  * Copyright (c) 2011, 2016, 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 
  26 package toolbox;
  27 
  28 import 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 public class Assert {
  36     /** Equivalent to
  37      *   assert cond;
  38      */
  39     public static void check(boolean cond) {
  40         if (!cond)
  41             error();
  42     }
  43 
  44     /** Equivalent to
  45      *   assert (o == null);
  46      */
  47     public static void checkNull(Object o) {
  48         if (o != null)
  49             error();
  50     }
  51 
  52     /** Equivalent to
  53      *   assert (t != null); return t;
  54      */
  55     public static <T> T checkNonNull(T t) {
  56         if (t == null)
  57             error();
  58         return t;
  59     }
  60 
  61     /** Equivalent to
  62      *   assert cond : value;
  63      */
  64     public static void check(boolean cond, int value) {
  65         if (!cond)
  66             error(String.valueOf(value));
  67     }
  68 
  69     /** Equivalent to
  70      *   assert cond : value;
  71      */
  72     public static void check(boolean cond, long value) {
  73         if (!cond)
  74             error(String.valueOf(value));
  75     }
  76 
  77     /** Equivalent to
  78      *   assert cond : value;
  79      */
  80     public static void check(boolean cond, Object value) {
  81         if (!cond)
  82             error(String.valueOf(value));
  83     }
  84 
  85     /** Equivalent to
  86      *   assert cond : msg;
  87      */
  88     public static void check(boolean cond, String msg) {
  89         if (!cond)
  90             error(msg);
  91     }
  92 
  93     /** Equivalent to
  94      *   assert cond : msg.get();
  95      *  Note: message string is computed lazily.
  96      */
  97     public static void check(boolean cond, Supplier<String> msg) {
  98         if (!cond)
  99             error(msg.get());
 100     }
 101 
 102     /** Equivalent to
 103      *   assert (o == null) : value;
 104      */
 105     public static void checkNull(Object o, Object value) {
 106         if (o != null)
 107             error(String.valueOf(value));
 108     }
 109 
 110     /** Equivalent to
 111      *   assert (o == null) : msg;
 112      */
 113     public static void checkNull(Object o, String msg) {
 114         if (o != null)
 115             error(msg);
 116     }
 117 
 118     /** Equivalent to
 119      *   assert (o == null) : msg.get();
 120      *  Note: message string is computed lazily.
 121      */
 122     public static void checkNull(Object o, Supplier<String> msg) {
 123         if (o != null)
 124             error(msg.get());
 125     }
 126 
 127     /** Equivalent to
 128      *   assert (o != null) : msg;
 129      */
 130     public static <T> T checkNonNull(T t, String msg) {
 131         if (t == null)
 132             error(msg);
 133         return t;
 134     }
 135 
 136     /** Equivalent to
 137      *   assert (o != null) : msg.get();
 138      *  Note: message string is computed lazily.
 139      */
 140     public static <T> T checkNonNull(T t, Supplier<String> msg) {
 141         if (t == null)
 142             error(msg.get());
 143         return t;
 144     }
 145 
 146     /** Equivalent to
 147      *   assert false;
 148      */
 149     public static void error() {
 150         throw new AssertionError();
 151     }
 152 
 153     /** Equivalent to
 154      *   assert false : msg;
 155      */
 156     public static void error(String msg) {
 157         throw new AssertionError(msg);
 158     }
 159 
 160     /** Prevent instantiation. */
 161     private Assert() { }
 162 }