Mega Code Archive
A mutable double 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.
*/
/**
* A mutable <code>double</code> wrapper.
*
* @see Double
* @since 2.1
* @version $Id: MutableDouble.java 618693 2008-02-05 16:33:29Z sebb $
*/
public class MutableDouble extends Number implements Comparable, Mutable {
/**
* Required for serialization support.
*
* @see java.io.Serializable
*/
private static final long serialVersionUID = 1587163916L;
/** The mutable value. */
private double value;
/**
* Constructs a new MutableDouble with the default value of zero.
*/
public MutableDouble() {
super();
}
/**
* Constructs a new MutableDouble with the specified value.
*
* @param value
* a value.
*/
public MutableDouble(double value) {
super();
this.value = value;
}
/**
* Constructs a new MutableDouble with the specified value.
*
* @param value
* a value.
* @throws NullPointerException
* if the object is null
*/
public MutableDouble(Number value) {
super();
this.value = value.doubleValue();
}
// -----------------------------------------------------------------------
/**
* Gets the value as a Double instance.
*
* @return the value as a Double
*/
public Object getValue() {
return new Double(this.value);
}
/**
* Sets the value.
*
* @param value
* the value to set
*/
public void setValue(double 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).doubleValue());
}
// -----------------------------------------------------------------------
// shortValue and bytValue rely on Number implementation
/**
* Returns the value of this MutableDouble 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 MutableDouble 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 MutableDouble as a float.
*
* @return the numeric value represented by this object after conversion to
* type float.
*/
public float floatValue() {
return (float) value;
}
/**
* Returns the value of this MutableDouble as a double.
*
* @return the numeric value represented by this object after conversion to
* type double.
*/
public double doubleValue() {
return value;
}
/**
* Checks whether the double value is the special NaN value.
*
* @return true if NaN
*/
public boolean isNaN() {
return Double.isNaN(value);
}
/**
* Checks whether the double value is infinite.
*
* @return true if infinite
*/
public boolean isInfinite() {
return Double.isInfinite(value);
}
// -----------------------------------------------------------------------
/**
* Gets this mutable as an instance of Double.
*
* @return a Double instance containing the value from this mutable
*/
public Double toDouble() {
return new Double(doubleValue());
}
// -----------------------------------------------------------------------
/**
* 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(double 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.doubleValue();
}
/**
* Subtracts a value.
*
* @param operand
* the value to add
*
* @since Commons Lang 2.2
*/
public void subtract(double 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.doubleValue();
}
// -----------------------------------------------------------------------
/**
* Compares this object against the specified object. The result is
* <code>true</code> if and only if the argument is not <code>null</code>
* and is a <code>Double</code> object that represents a double that has the
* identical bit pattern to the bit pattern of the double represented by this
* object. For this purpose, two <code>double</code> values are considered
* to be the same if and only if the method
* {@link Double#doubleToLongBits(double)}returns the same long value when
* applied to each.
* <p>
* Note that in most cases, for two instances of class <code>Double</code>,<code>d1</code>
* and <code>d2</code>, the value of <code>d1.equals(d2)</code> is
* <code>true</code> if and only if <blockquote>
*
* <pre>
* d1.doubleValue() == d2.doubleValue()
* </pre>
*
* </blockquote>
* <p>
* also has the value <code>true</code>. However, there are two exceptions:
* <ul>
* <li>If <code>d1</code> and <code>d2</code> both represent
* <code>Double.NaN</code>, then the <code>equals</code> method returns
* <code>true</code>, even though <code>Double.NaN==Double.NaN</code> has
* the value <code>false</code>.
* <li>If <code>d1</code> represents <code>+0.0</code> while
* <code>d2</code> represents <code>-0.0</code>, or vice versa, the
* <code>equal</code> test has the value <code>false</code>, even though
* <code>+0.0==-0.0</code> has the value <code>true</code>. This allows
* hashtables to operate properly.
* </ul>
*
* @param obj
* the object to compare with.
* @return <code>true</code> if the objects are the same; <code>false</code>
* otherwise.
*/
public boolean equals(Object obj) {
return (obj instanceof MutableDouble)
&& (Double.doubleToLongBits(((MutableDouble) obj).value) == Double.doubleToLongBits(value));
}
/**
* Returns a suitable hashcode for this mutable.
*
* @return a suitable hashcode
*/
public int hashCode() {
long bits = Double.doubleToLongBits(value);
return (int) (bits ^ (bits >>> 32));
}
/**
* 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
* @throws ClassCastException
* if the argument is not a MutableDouble
*/
public int compareTo(Object obj) {
MutableDouble other = (MutableDouble) obj;
double anotherVal = other.value;
return compare(value, anotherVal);
}
/**
* Returns the String value of this mutable.
*
* @return the mutable value as a string
*/
public String toString() {
return String.valueOf(value);
}
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);
}
}
}
/*
* 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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