Mega Code Archive
A mutable float wrapper
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/*
* 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.
*/
//Revised from commons lang Apache
/**
* A mutable <code>float</code> wrapper.
*
* @see Float
* @since 2.1
* @version $Id: MutableFloat.java 618693 2008-02-05 16:33:29Z sebb $
*/
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 compare(value, anotherVal);
}
protected int compare(Object o1, Object o2) {
if (o1 == null) {
if (o2 == null) {
return 0;
} else {
return -((Comparable) o2).compareTo(o1);
}
} else {
return ((Comparable) o1).compareTo(o2);
}
}
/**
* Returns the String value of this mutable.
*
* @return the mutable value as a string
*/
public String toString() {
return String.valueOf(value);
}
}
/*
* 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.
*/
/**
* Provides mutable access to a value.
* <p>
* <code>Mutable</code> is used as a generic interface to the implementations
* in this package.
* <p>
* A typical use case would be to enable a primitive or string to be passed to a
* method and allow that method to effectively change the value of the
* primitive/string. Another use case is to store a frequently changing
* primitive in a collection (for example a total in a map) without needing to
* create new Integer/Long wrapper objects.
*
* @author Matthew Hawthorne
* @since 2.1
* @version $Id: Mutable.java 618693 2008-02-05 16:33:29Z sebb $
*/
interface Mutable {
/**
* Gets the value of this mutable.
*
* @return the stored value
*/
Object getValue();
/**
* Sets the value of this mutable.
*
* @param value
* the value to store
* @throws NullPointerException
* if the object is null and null is invalid
* @throws ClassCastException
* if the type is invalid
*/
void setValue(Object value);
}
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