code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.lang.mutable;
  
  import org.apache.commons.lang.math.NumberUtils;
  
  /**
   * A mutable <code>float</code> wrapper.
   * 
   * @see Float
   * @since 2.1
   * @version $Id: MutableFloat.java 437554 2006-08-28 06:21:41Z bayard $
   */
  public class MutableFloat extends Number implements Comparable, Mutable {
  
      /**
       * Required for serialization support.
       * 
       * @see java.io.Serializable
       */
      private static final long serialVersionUID = 5787169186L;
  
      /** The mutable value. */
      private float value;
  
      /**
       * Constructs a new MutableFloat with the default value of zero.
       */
      public MutableFloat() {
          super();
      }
  
      /**
       * Constructs a new MutableFloat with the specified value.
       * 
       * @param value
       *            a value.
       */
      public MutableFloat(float value) {
          super();
          this.value = value;
      }
  
      /**
       * Constructs a new MutableFloat with the specified value.
       * 
       * @param value
       *            a value.
       * @throws NullPointerException
       *             if the object is null
       */
      public MutableFloat(Number value) {
          super();
          this.value = value.floatValue();
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets the value as a Float instance.
       * 
       * @return the value as a Float
       */
      public Object getValue() {
          return new Float(this.value);
      }
  
      /**
       * Sets the value.
       * 
       * @param value
       *            the value to set
       */
      public void setValue(float value) {
          this.value = value;
      }
  
      /**
       * Sets the value from any Number instance.
       * 
       * @param value
       *            the value to set
       * @throws NullPointerException
       *             if the object is null
       * @throws ClassCastException
       *             if the type is not a {@link Number}
       */
      public void setValue(Object value) {
          setValue(((Number) value).floatValue());
      }
  
      //-----------------------------------------------------------------------
      /**
       * Increments the value.
       *
       * @since Commons Lang 2.2
       */
      public void increment() {
          value++;
      }
  
      /**
       * Decrements the value.
       *
       * @since Commons Lang 2.2
       */
      public void decrement() {
          value--;
      }
  
      //-----------------------------------------------------------------------
      /**
       * Adds a value.
       * 
       * @param operand
       *            the value to add
       *
       * @since Commons Lang 2.2
       */
      public void add(float operand) {
          this.value += operand;
      }
  
      /**
       * Adds a value.
       * 
       * @param operand
       *            the value to add
       * @throws NullPointerException
       *             if the object is null
       *
       * @since Commons Lang 2.2
       */
      public void add(Number operand) {
          this.value += operand.floatValue();
      }
  
      /**
       * Subtracts a value.
       * 
       * @param operand
       *            the value to add
       *
       * @since Commons Lang 2.2
       */
      public void subtract(float operand) {
          this.value -= operand;
      }
  
      /**
       * Subtracts a value.
       * 
       * @param operand
       *            the value to add
       * @throws NullPointerException
       *             if the object is null
       *
       * @since Commons Lang 2.2
       */
      public void subtract(Number operand) {
          this.value -= operand.floatValue();
      }
  
      //-----------------------------------------------------------------------
      // shortValue and bytValue rely on Number implementation
      /**
       * Returns the value of this MutableFloat as a int.
       *
       * @return the numeric value represented by this object after conversion to type int.
       */
      public int intValue() {
          return (int) value;
      }
  
      /**
       * Returns the value of this MutableFloat as a long.
       *
       * @return the numeric value represented by this object after conversion to type long.
       */
      public long longValue() {
          return (long) value;
      }
  
      /**
       * Returns the value of this MutableFloat as a float.
       *
       * @return the numeric value represented by this object after conversion to type float.
       */
      public float floatValue() {
          return value;
      }
  
      /**
       * Returns the value of this MutableFloat as a double.
       *
       * @return the numeric value represented by this object after conversion to type double.
       */
      public double doubleValue() {
          return value;
      }
  
      /**
       * Checks whether the float value is the special NaN value.
       * 
       * @return true if NaN
       */
      public boolean isNaN() {
          return Float.isNaN(value);
      }
  
      /**
       * Checks whether the float value is infinite.
       * 
       * @return true if infinite
       */
      public boolean isInfinite() {
          return Float.isInfinite(value);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets this mutable as an instance of Float.
       *
       * @return a Float instance containing the value from this mutable
       */
      public Float toFloat() {
          return new Float(floatValue());
      }
  
      //-----------------------------------------------------------------------
      /**
       * Compares this object against some other object. The result is <code>true</code> if and only if the argument is
       * not <code>null</code> and is a <code>Float</code> object that represents a <code>float</code> that has the
       * identical bit pattern to the bit pattern of the <code>float</code> represented by this object. For this
       * purpose, two float values are considered to be the same if and only if the method
       * {@link Float#floatToIntBits(float)}returns the same int value when applied to each.
       * <p>
       * Note that in most cases, for two instances of class <code>Float</code>,<code>f1</code> and <code>f2</code>,
       * the value of <code>f1.equals(f2)</code> is <code>true</code> if and only if <blockquote>
       * 
       * <pre>
       *   f1.floatValue() == f2.floatValue()
       * </pre>
       * 
       * </blockquote>
       * <p>
       * also has the value <code>true</code>. However, there are two exceptions:
       * <ul>
       * <li>If <code>f1</code> and <code>f2</code> both represent <code>Float.NaN</code>, then the
       * <code>equals</code> method returns <code>true</code>, even though <code>Float.NaN==Float.NaN</code> has
       * the value <code>false</code>.
       * <li>If <code>f1</code> represents <code>+0.0f</code> while <code>f2</code> represents <code>-0.0f</code>,
       * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though
       * <code>0.0f==-0.0f</code> has the value <code>true</code>.
       * </ul>
       * This definition allows hashtables to operate properly.
       * 
       * @param obj
       *            the object to be compared
       * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
       * @see java.lang.Float#floatToIntBits(float)
       */
      public boolean equals(Object obj) {
          return (obj instanceof MutableFloat)
              && (Float.floatToIntBits(((MutableFloat) obj).value) == Float.floatToIntBits(value));
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a suitable hashcode for this mutable.
       * 
       * @return a suitable hashcode
       */
      public int hashCode() {
          return Float.floatToIntBits(value);
      }
  
      /**
       * Compares this mutable to another in ascending order.
       * 
       * @param obj
       *            the mutable to compare to
       * @return negative if this is less, zero if equal, positive if greater
       */
      public int compareTo(Object obj) {
          MutableFloat other = (MutableFloat) obj;
          float anotherVal = other.value;
          return NumberUtils.compare(value, anotherVal);
      }
  
      /**
       * Returns the String value of this mutable.
       * 
       * @return the mutable value as a string
       */
      public String toString() {
          return String.valueOf(value);
      }
  
  }
  