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package com.jidesoft.comparator;

import java.util.Comparator;

/**
 * Comparator for Number type. This is a singleton class. Call getInstance() to get the comparator.
 */
public class NumberComparator implements Comparator {
    /**
     * Comparator Context to compare two values using the absolute value.
     */
    public static final ComparatorContext CONTEXT_ABSOLUTE = new ComparatorContext("AbsoluteValue");

    private static NumberComparator singleton = null;

    private boolean _absolute = false;

    /**
     * Constructor.
     * 

* Has protected access to prevent other clients creating instances of the class ... it is stateless so we need only * one instance. */ protected NumberComparator() { } /** * Returns NumberComparator singleton. * * @return an instance of NumberComparator. */ public static NumberComparator getInstance() { if (singleton == null) singleton = new NumberComparator(); return singleton; } /** * Compares two Numbers. * * @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 comparable 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 comparable throw new ClassCastException( "The second argument of this method was not a Number but " + o1.getClass().getName() ); } else { // neither were comparable 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; } }