IntegerReuseable


1   /*
2    *  IntegerReusable.java, a mutable Integer for  jchart2d.
3    *  Copyright (C) Achim Westermann, created on 12.05.2005, 20:11:17
4    *
5    *  This library is free software; you can redistribute it and/or
6    *  modify it under the terms of the GNU Lesser General Public
7    *  License as published by the Free Software Foundation; either
8    *  version 2.1 of the License, or (at your option) any later version.
9    * 
10   *  This library is distributed in the hope that it will be useful,
11   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   *  Lesser General Public License for more details.
14   * 
15   *  You should have received a copy of the GNU Lesser General Public
16   *  License along with this library; if not, write to the Free Software
17   *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18   *
19   *  If you modify or optimize the code in a useful way please let me know.
20   *  Achim.Westermann@gmx.de
21   *
22   */
23  package info.monitorenter.util.math;
24  
25  /**
26   * Mutable {@link java.lang.Integer}.
27   * <p>
28   *
29   * I needed an wrapper of an primitive int to share the same value between
30   * different instances and to have the changes made to the primitive value take
31   * effect on all owners of the same instance.
32   * <p>
33   *
34   * What a pity that java.lang.Integer does not allow to change it's internal
35   * value at runtime. Every time a new Integer has to be constructed.
36   * <p>
37   *
38   */
39  public class IntegerReuseable {
40  
41    /**
42     * The largest value of type <code>int</code>. The constant value of this
43     * field is <tt>2147483647</tt>.
44     */
45    public static final int MAX_VALUE = 0x7fffffff;
46  
47    /**
48     * The smallest value of type <code>int</code>. The constant value of this
49     * field is <tt>-2147483648</tt>.
50     */
51    public static final int MIN_VALUE = 0x80000000;
52  
53    /**
54     * The value of the Integer.
55     */
56    private int m_value;
57  
58    /**
59     * Constructs a newly allocated <code>Integer</code> object that represents
60     * the primitive <code>int</code> argument.
61     *
62     * @param value
63     *          the value to be represented by the <code>Integer</code>.
64     */
65    public IntegerReuseable(final int value) {
66      this.m_value = value;
67    }
68  
69    /**
70     * Adds the given value to the internal value.
71     * <p>
72     *
73     * @param i
74     *          the value to add.
75     *
76     * @throws ArithmeticException
77     *           if an overflow ({@link Integer#MAX_VALUE}) occurs.
78     */
79    public void add(final int i) throws ArithmeticException   {
80      int oldval = this.m_value;
81      this.m_value += i;
82      if (oldval > this.m_value) {
83        this.m_value = oldval;
84        throw new ArithmeticException  ("Overflow detected. Value saved unchanged.");
85      }
86    }
87  
88    /**
89     * Adds the given value to the internal value.
90     * <p>
91     *
92     * @param i
93     *          the value to add.
94     *
95     * @throws ArithmeticException
96     *           if an overflow ({@link Integer#MAX_VALUE}) occurs.
97     */
98    public void add(final Integer   i) throws ArithmeticException   {
99      this.add(i.intValue());
100   }
101 
102   /**
103    * Adds the given value to the internal value.
104    * <p>
105    *
106    * @param i
107    *          the value to add.
108    *
109    * @throws ArithmeticException
110    *           if an overflow ({@link Integer#MAX_VALUE}) occurs.
111    */
112   public void add(final IntegerReuseable i) throws ArithmeticException   {
113     this.add(i.getValue());
114   }
115 
116   /**
117    * Returns the value as an int.
118    * <p>
119    *
120    * @return the value as an int.
121    */
122   public int getValue() {
123     return this.m_value;
124   }
125 
126   /**
127    * Returns the value as an int.
128    * <p>
129    *
130    * @return the value as an int.
131    */
132   public int intValue() {
133     return this.m_value;
134   }
135 
136   /**
137    * Sets the value.
138    * <p>
139    *
140    * @param value
141    *          the value.
142    */
143   public void setValue(final int value) {
144     this.m_value = value;
145   }
146 
147   /**
148    * Substracts the given value from the internal value.
149    * <p>
150    *
151    * @param i
152    *          the value to subtract.
153    *
154    * @throws ArithmeticException
155    *           if a carry ({@link Integer#MIN_VALUE}) occurs.
156    */
157   public void sub(final int i) throws ArithmeticException   {
158     int oldval = this.m_value;
159     this.m_value -= i;
160     if (oldval < this.m_value) {
161       this.m_value = oldval;
162       throw new ArithmeticException  ("Carry detected. Value saved unchanged.");
163     }
164   }
165 
166   /**
167    * Substracts the given value from the internal value.
168    * <p>
169    *
170    * @param i
171    *          the value to subtract.
172    *
173    * @throws ArithmeticException
174    *           if a carry ({@link Integer#MIN_VALUE}) occurs.
175    */
176   public void sub(final Integer   i) throws ArithmeticException   {
177     this.sub(i.intValue());
178   }
179 
180   /**
181    * Substracts the given value from the internal value.
182    * <p>
183    *
184    * @param i
185    *          the value to subtract.
186    *
187    * @throws ArithmeticException
188    *           if a carry ({@link Integer#MIN_VALUE}) occurs.
189    */
190   public void sub(final IntegerReuseable i) throws ArithmeticException   {
191     this.sub(i.intValue());
192   }
193 
194   /**
195    * Returns a String object representing this Integer's value.
196    * <p>
197    *
198    * The value is converted to signed decimal representation and returned as a
199    * string, exactly as if the integer value were given as an argument to the
200    * {@link java.lang.Integer#toString(int)} method.
201    * <p>
202    *
203    *
204    * @return a string representation of the value of this object in
205    *         base&nbsp;10.
206    */
207   public String   toString() {
208     return String.valueOf(this.m_value);
209   }
210 }
211
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