/*
* Copyright (c) 2002-2015, JIDE Software Inc. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package jidefx.utils.comparator;
import java.util.Comparator;
/**
* Comparator for Number type which supports a context to compare the absolute values. This is a singleton class. Call
* getInstance() to get the comparator.
*/
public class NumberComparator implements Comparator<Object> {
/**
* Comparator Context to compare two values using the absolute value.
*/
public static final ComparatorContext CONTEXT_ABSOLUTE = new ComparatorContext("AbsoluteValue"); //NON-NLS
private static NumberComparator singleton = null;
private boolean _absolute = false;
/**
* Constructor.
* <p/>
* Has protected access to prevent other clients creating instances of the class ... it is stateless so we need only
* one instance.
*/
protected NumberComparator() {
}
/**
* Returns <tt>NumberComparator</tt> singleton.
*
* @return an instance of NumberComparator.
*/
public static NumberComparator getInstance() {
if (singleton == null)
singleton = new NumberComparator();
return singleton;
}
/**
* Compares two <tt>Number</tt>s.
*
* @param o1 the first object to be compared
* @param o2 the second object to be compared
* @return 0 if a and b are equal, -1 if a is less than b, 1 if a is more than b.
*/
public int compare(Object o1, Object o2) {
if (o1 == null && o2 == null) {
return 0;
}
else if (o1 == null) {
return -1;
}
else if (o2 == null) {
return 1;
}
if (o1 instanceof Number) {
if (o2 instanceof Number) {
long l1 = 0;
long l2 = 0;
double d1 = 0;
double d2 = 0;
if (o1 instanceof Long) {
l1 = ((Number) o1).longValue();
}
else {
d1 = ((Number) o1).doubleValue();
}
if (o2 instanceof Long) {
l2 = ((Number) o2).longValue();
}
else {
d2 = ((Number) o2).doubleValue();
}
if (isAbsolute()) {
if (d1 < 0) {
d1 = -d1;
}
if (d2 < 0) {
d2 = -d2;
}
if (l1 < 0) {
l1 = -l1;
}
if (l2 < 0) {
l2 = -l2;
}
}
if (o1 instanceof Long && o2 instanceof Long) {
if (l1 < l2)
return -1;
else if (l1 > l2)
return 1;
else
return 0;
}
else if (o1 instanceof Long) {
if (l1 < d2)
return -1;
else if (l1 > d2)
return 1;
else
return 0;
}
else if (o2 instanceof Long) {
if (d1 < l2)
return -1;
else if (d1 > l2)
return 1;
else
return 0;
}
else {
if (d1 < d2)
return -1;
else if (d1 > d2)
return 1;
else
return 0;
}
}
else {
// o2 wasn't Number
throw new ClassCastException("The first argument of this method was not a Number but " + o2.getClass().getName());
}
}
else if (o2 instanceof Number) {
// o1 wasn't Number
throw new ClassCastException("The second argument of this method was not a Number but " + o1.getClass().getName()
);
}
else {
// neither were Number
throw new ClassCastException("Both arguments of this method were not Numbers. They are " + o1.getClass().getName() + " and " + o2.getClass().getName()
);
}
}
/**
* Checks if if the values are compared using the absolute values.
*
* @return true or false.
*/
public boolean isAbsolute() {
return _absolute;
}
/**
* Sets the flag to compare the values using the absolute value.
*
* @param absolute true or false.
*/
public void setAbsolute(boolean absolute) {
_absolute = absolute;
}
}