001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.lang.mutable;
018
019 import org.apache.commons.lang.math.NumberUtils;
020
021 /**
022 * A mutable <code>float</code> wrapper.
023 *
024 * @see Float
025 * @since 2.1
026 * @author Apache Software Foundation
027 * @version $Id: MutableFloat.java 905707 2010-02-02 16:59:59Z niallp $
028 */
029 public class MutableFloat extends Number implements Comparable, Mutable {
030
031 /**
032 * Required for serialization support.
033 *
034 * @see java.io.Serializable
035 */
036 private static final long serialVersionUID = 5787169186L;
037
038 /** The mutable value. */
039 private float value;
040
041 /**
042 * Constructs a new MutableFloat with the default value of zero.
043 */
044 public MutableFloat() {
045 super();
046 }
047
048 /**
049 * Constructs a new MutableFloat with the specified value.
050 *
051 * @param value the initial value to store
052 */
053 public MutableFloat(float value) {
054 super();
055 this.value = value;
056 }
057
058 /**
059 * Constructs a new MutableFloat with the specified value.
060 *
061 * @param value the initial value to store, not null
062 * @throws NullPointerException if the object is null
063 */
064 public MutableFloat(Number value) {
065 super();
066 this.value = value.floatValue();
067 }
068
069 /**
070 * Constructs a new MutableFloat parsing the given string.
071 *
072 * @param value the string to parse, not null
073 * @throws NumberFormatException if the string cannot be parsed into a float
074 * @since 2.5
075 */
076 public MutableFloat(String value) throws NumberFormatException {
077 super();
078 this.value = Float.parseFloat(value);
079 }
080
081 //-----------------------------------------------------------------------
082 /**
083 * Gets the value as a Float instance.
084 *
085 * @return the value as a Float, never null
086 */
087 public Object getValue() {
088 return new Float(this.value);
089 }
090
091 /**
092 * Sets the value.
093 *
094 * @param value the value to set
095 */
096 public void setValue(float value) {
097 this.value = value;
098 }
099
100 /**
101 * Sets the value from any Number instance.
102 *
103 * @param value the value to set, not null
104 * @throws NullPointerException if the object is null
105 * @throws ClassCastException if the type is not a {@link Number}
106 */
107 public void setValue(Object value) {
108 setValue(((Number) value).floatValue());
109 }
110
111 //-----------------------------------------------------------------------
112 /**
113 * Checks whether the float value is the special NaN value.
114 *
115 * @return true if NaN
116 */
117 public boolean isNaN() {
118 return Float.isNaN(value);
119 }
120
121 /**
122 * Checks whether the float value is infinite.
123 *
124 * @return true if infinite
125 */
126 public boolean isInfinite() {
127 return Float.isInfinite(value);
128 }
129
130 //-----------------------------------------------------------------------
131 /**
132 * Increments the value.
133 *
134 * @since Commons Lang 2.2
135 */
136 public void increment() {
137 value++;
138 }
139
140 /**
141 * Decrements the value.
142 *
143 * @since Commons Lang 2.2
144 */
145 public void decrement() {
146 value--;
147 }
148
149 //-----------------------------------------------------------------------
150 /**
151 * Adds a value to the value of this instance.
152 *
153 * @param operand the value to add, not null
154 * @since Commons Lang 2.2
155 */
156 public void add(float operand) {
157 this.value += operand;
158 }
159
160 /**
161 * Adds a value to the value of this instance.
162 *
163 * @param operand the value to add, not null
164 * @throws NullPointerException if the object is null
165 * @since Commons Lang 2.2
166 */
167 public void add(Number operand) {
168 this.value += operand.floatValue();
169 }
170
171 /**
172 * Subtracts a value from the value of this instance.
173 *
174 * @param operand the value to subtract
175 * @since Commons Lang 2.2
176 */
177 public void subtract(float operand) {
178 this.value -= operand;
179 }
180
181 /**
182 * Subtracts a value from the value of this instance.
183 *
184 * @param operand the value to subtract, not null
185 * @throws NullPointerException if the object is null
186 * @since Commons Lang 2.2
187 */
188 public void subtract(Number operand) {
189 this.value -= operand.floatValue();
190 }
191
192 //-----------------------------------------------------------------------
193 // shortValue and bytValue rely on Number implementation
194 /**
195 * Returns the value of this MutableFloat as an int.
196 *
197 * @return the numeric value represented by this object after conversion to type int.
198 */
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 public long longValue() {
209 return (long) value;
210 }
211
212 /**
213 * Returns the value of this MutableFloat as a float.
214 *
215 * @return the numeric value represented by this object after conversion to type float.
216 */
217 public float floatValue() {
218 return value;
219 }
220
221 /**
222 * Returns the value of this MutableFloat as a double.
223 *
224 * @return the numeric value represented by this object after conversion to type double.
225 */
226 public double doubleValue() {
227 return value;
228 }
229
230 //-----------------------------------------------------------------------
231 /**
232 * Gets this mutable as an instance of Float.
233 *
234 * @return a Float instance containing the value from this mutable, never null
235 */
236 public Float toFloat() {
237 return new Float(floatValue());
238 }
239
240 //-----------------------------------------------------------------------
241 /**
242 * Compares this object against some other object. The result is <code>true</code> if and only if the argument is
243 * not <code>null</code> and is a <code>Float</code> object that represents a <code>float</code> that has the
244 * identical bit pattern to the bit pattern of the <code>float</code> represented by this object. For this
245 * purpose, two float values are considered to be the same if and only if the method
246 * {@link Float#floatToIntBits(float)}returns the same int value when applied to each.
247 * <p>
248 * Note that in most cases, for two instances of class <code>Float</code>,<code>f1</code> and <code>f2</code>,
249 * the value of <code>f1.equals(f2)</code> is <code>true</code> if and only if <blockquote>
250 *
251 * <pre>
252 * f1.floatValue() == f2.floatValue()
253 * </pre>
254 *
255 * </blockquote>
256 * <p>
257 * also has the value <code>true</code>. However, there are two exceptions:
258 * <ul>
259 * <li>If <code>f1</code> and <code>f2</code> both represent <code>Float.NaN</code>, then the
260 * <code>equals</code> method returns <code>true</code>, even though <code>Float.NaN==Float.NaN</code> has
261 * the value <code>false</code>.
262 * <li>If <code>f1</code> represents <code>+0.0f</code> while <code>f2</code> represents <code>-0.0f</code>,
263 * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though
264 * <code>0.0f==-0.0f</code> has the value <code>true</code>.
265 * </ul>
266 * This definition allows hashtables to operate properly.
267 *
268 * @param obj the object to compare with, null returns false
269 * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
270 * @see java.lang.Float#floatToIntBits(float)
271 */
272 public boolean equals(Object obj) {
273 return (obj instanceof MutableFloat)
274 && (Float.floatToIntBits(((MutableFloat) obj).value) == Float.floatToIntBits(value));
275 }
276
277 /**
278 * Returns a suitable hash code for this mutable.
279 *
280 * @return a suitable hash code
281 */
282 public int hashCode() {
283 return Float.floatToIntBits(value);
284 }
285
286 //-----------------------------------------------------------------------
287 /**
288 * Compares this mutable to another in ascending order.
289 *
290 * @param obj the other mutable to compare to, not null
291 * @return negative if this is less, zero if equal, positive if greater
292 */
293 public int compareTo(Object obj) {
294 MutableFloat other = (MutableFloat) obj;
295 float anotherVal = other.value;
296 return NumberUtils.compare(value, anotherVal);
297 }
298
299 //-----------------------------------------------------------------------
300 /**
301 * Returns the String value of this mutable.
302 *
303 * @return the mutable value as a string
304 */
305 public String toString() {
306 return String.valueOf(value);
307 }
308
309 }