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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.lang3.mutable;
18  
19  /**
20   * A mutable <code>float</code> wrapper.
21   * <p>
22   * Note that as MutableFloat does not extend Float, it is not treated by String.format as a Float parameter. 
23   * 
24   * @see Float
25   * @since 2.1
26   */
27  public class MutableFloat extends Number implements Comparable<MutableFloat>, Mutable<Number> {
28  
29      /**
30       * Required for serialization support.
31       * 
32       * @see java.io.Serializable
33       */
34      private static final long serialVersionUID = 5787169186L;
35  
36      /** The mutable value. */
37      private float value;
38  
39      /**
40       * Constructs a new MutableFloat with the default value of zero.
41       */
42      public MutableFloat() {
43          super();
44      }
45  
46      /**
47       * Constructs a new MutableFloat with the specified value.
48       * 
49       * @param value  the initial value to store
50       */
51      public MutableFloat(final float value) {
52          super();
53          this.value = value;
54      }
55  
56      /**
57       * Constructs a new MutableFloat with the specified value.
58       * 
59       * @param value  the initial value to store, not null
60       * @throws NullPointerException if the object is null
61       */
62      public MutableFloat(final Number value) {
63          super();
64          this.value = value.floatValue();
65      }
66  
67      /**
68       * Constructs a new MutableFloat parsing the given string.
69       * 
70       * @param value  the string to parse, not null
71       * @throws NumberFormatException if the string cannot be parsed into a float
72       * @since 2.5
73       */
74      public MutableFloat(final String value) throws NumberFormatException {
75          super();
76          this.value = Float.parseFloat(value);
77      }
78  
79      //-----------------------------------------------------------------------
80      /**
81       * Gets the value as a Float instance.
82       * 
83       * @return the value as a Float, never null
84       */
85      @Override
86      public Float getValue() {
87          return Float.valueOf(this.value);
88      }
89  
90      /**
91       * Sets the value.
92       * 
93       * @param value  the value to set
94       */
95      public void setValue(final float value) {
96          this.value = value;
97      }
98  
99      /**
100      * Sets the value from any Number instance.
101      * 
102      * @param value  the value to set, not null
103      * @throws NullPointerException if the object is null
104      */
105     @Override
106     public void setValue(final Number value) {
107         this.value = value.floatValue();
108     }
109 
110     //-----------------------------------------------------------------------
111     /**
112      * Checks whether the float value is the special NaN value.
113      * 
114      * @return true if NaN
115      */
116     public boolean isNaN() {
117         return Float.isNaN(value);
118     }
119 
120     /**
121      * Checks whether the float value is infinite.
122      * 
123      * @return true if infinite
124      */
125     public boolean isInfinite() {
126         return Float.isInfinite(value);
127     }
128 
129     //-----------------------------------------------------------------------
130     /**
131      * Increments the value.
132      *
133      * @since Commons Lang 2.2
134      */
135     public void increment() {
136         value++;
137     }
138 
139     /**
140      * Decrements the value.
141      *
142      * @since Commons Lang 2.2
143      */
144     public void decrement() {
145         value--;
146     }
147 
148     //-----------------------------------------------------------------------
149     /**
150      * Adds a value to the value of this instance.
151      * 
152      * @param operand  the value to add, not null
153      * @since Commons Lang 2.2
154      */
155     public void add(final float operand) {
156         this.value += operand;
157     }
158 
159     /**
160      * Adds a value to the value of this instance.
161      * 
162      * @param operand  the value to add, not null
163      * @throws NullPointerException if the object is null
164      * @since Commons Lang 2.2
165      */
166     public void add(final Number operand) {
167         this.value += operand.floatValue();
168     }
169 
170     /**
171      * Subtracts a value from the value of this instance.
172      * 
173      * @param operand  the value to subtract
174      * @since Commons Lang 2.2
175      */
176     public void subtract(final float operand) {
177         this.value -= operand;
178     }
179 
180     /**
181      * Subtracts a value from the value of this instance.
182      * 
183      * @param operand  the value to subtract, not null
184      * @throws NullPointerException if the object is null
185      * @since Commons Lang 2.2
186      */
187     public void subtract(final Number operand) {
188         this.value -= operand.floatValue();
189     }
190 
191     //-----------------------------------------------------------------------
192     // shortValue and byteValue rely on Number implementation
193     /**
194      * Returns the value of this MutableFloat as an int.
195      *
196      * @return the numeric value represented by this object after conversion to type int.
197      */
198     @Override
199     public int intValue() {
200         return (int) value;
201     }
202 
203     /**
204      * Returns the value of this MutableFloat as a long.
205      *
206      * @return the numeric value represented by this object after conversion to type long.
207      */
208     @Override
209     public long longValue() {
210         return (long) value;
211     }
212 
213     /**
214      * Returns the value of this MutableFloat as a float.
215      *
216      * @return the numeric value represented by this object after conversion to type float.
217      */
218     @Override
219     public float floatValue() {
220         return value;
221     }
222 
223     /**
224      * Returns the value of this MutableFloat as a double.
225      *
226      * @return the numeric value represented by this object after conversion to type double.
227      */
228     @Override
229     public double doubleValue() {
230         return value;
231     }
232 
233     //-----------------------------------------------------------------------
234     /**
235      * Gets this mutable as an instance of Float.
236      *
237      * @return a Float instance containing the value from this mutable, never null
238      */
239     public Float toFloat() {
240         return Float.valueOf(floatValue());
241     }
242 
243     //-----------------------------------------------------------------------
244     /**
245      * Compares this object against some other object. The result is <code>true</code> if and only if the argument is
246      * not <code>null</code> and is a <code>Float</code> object that represents a <code>float</code> that has the
247      * identical bit pattern to the bit pattern of the <code>float</code> represented by this object. For this
248      * purpose, two float values are considered to be the same if and only if the method
249      * {@link Float#floatToIntBits(float)}returns the same int value when applied to each.
250      * <p>
251      * Note that in most cases, for two instances of class <code>Float</code>,<code>f1</code> and <code>f2</code>,
252      * the value of <code>f1.equals(f2)</code> is <code>true</code> if and only if <blockquote>
253      * 
254      * <pre>
255      *   f1.floatValue() == f2.floatValue()
256      * </pre>
257      * 
258      * </blockquote>
259      * <p>
260      * also has the value <code>true</code>. However, there are two exceptions:
261      * <ul>
262      * <li>If <code>f1</code> and <code>f2</code> both represent <code>Float.NaN</code>, then the
263      * <code>equals</code> method returns <code>true</code>, even though <code>Float.NaN==Float.NaN</code> has
264      * the value <code>false</code>.
265      * <li>If <code>f1</code> represents <code>+0.0f</code> while <code>f2</code> represents <code>-0.0f</code>,
266      * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though
267      * <code>0.0f==-0.0f</code> has the value <code>true</code>.
268      * </ul>
269      * This definition allows hashtables to operate properly.
270      * 
271      * @param obj  the object to compare with, null returns false
272      * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
273      * @see java.lang.Float#floatToIntBits(float)
274      */
275     @Override
276     public boolean equals(final Object obj) {
277         return obj instanceof MutableFloat
278             && Float.floatToIntBits(((MutableFloat) obj).value) == Float.floatToIntBits(value);
279     }
280 
281     /**
282      * Returns a suitable hash code for this mutable.
283      * 
284      * @return a suitable hash code
285      */
286     @Override
287     public int hashCode() {
288         return Float.floatToIntBits(value);
289     }
290 
291     //-----------------------------------------------------------------------
292     /**
293      * Compares this mutable to another in ascending order.
294      * 
295      * @param other  the other mutable to compare to, not null
296      * @return negative if this is less, zero if equal, positive if greater
297      */
298     @Override
299     public int compareTo(final MutableFloat other) {
300         return Float.compare(this.value, other.value);
301     }
302 
303     //-----------------------------------------------------------------------
304     /**
305      * Returns the String value of this mutable.
306      * 
307      * @return the mutable value as a string
308      */
309     @Override
310     public String toString() {
311         return String.valueOf(value);
312     }
313 
314 }