/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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 Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.states.crosstab;
import java.util.Comparator;
public class CrosstabKeyComparator implements Comparator<Object[]> {
public static final CrosstabKeyComparator INSTANCE = new CrosstabKeyComparator();
public CrosstabKeyComparator() {
}
/**
* Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument
* is less than, equal to, or greater than the second.
* <p>
* <p/>
* The implementor must ensure that <tt>sgn(compare(x, y)) == -sgn(compare(y, x))</tt> for all <tt>x</tt> and
* <tt>y</tt>. (This implies that <tt>compare(x, y)</tt> must throw an exception if and only if <tt>compare(y,
* x)</tt> throws an exception.)
* <p>
* <p/>
* The implementor must also ensure that the relation is transitive: <tt>((compare(x, y)>0) && (compare(y,
* z)>0))</tt> implies <tt>compare(x, z)>0</tt>.
* <p>
* <p/>
* Finally, the implementer must ensure that <tt>compare(x, y)==0</tt> implies that <tt>sgn(compare(x,
* z))==sgn(compare(y, z))</tt> for all <tt>z</tt>.
* <p>
* <p/>
* It is generally the case, but <i>not</i> strictly required that <tt>(compare(x, y)==0) == (x.equals(y))</tt>.
* Generally speaking, any comparator that violates this condition should clearly indicate this fact. The recommended
* language is "Note: this comparator imposes orderings that are inconsistent with equals."
*
* @param key1
* the first object to be compared.
* @param key2
* the second object to be compared.
* @return a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater
* than the second.
* @throws ClassCastException
* if the arguments' types prevent them from being compared by this Comparator.
*/
@SuppressWarnings( "unchecked" )
public int compare( final Object[] key1, final Object[] key2 ) {
if ( key1 == null || key2 == null ) {
throw new IllegalArgumentException( "All keys must be non-null" );
}
final int length = key1.length;
if ( length != key2.length ) {
throw new IllegalArgumentException( "All keys must have the same length" );
}
for ( int i = 0; i < length; i++ ) {
final Object value1 = key1[i];
final Object value2 = key2[i];
if ( value1 == null && value2 == null ) {
continue;
}
if ( value1 == null ) {
return -1;
}
if ( value2 == null ) {
return +1;
}
if ( value1 instanceof Number && value2 instanceof Number ) {
final Number n1 = (Number) value1;
final Number n2 = (Number) value2;
final double d1 = n1.doubleValue();
final double d2 = n2.doubleValue();
if ( d1 < d2 ) {
return -1;
}
if ( d1 > d2 ) {
return +1;
}
continue;
}
if ( value1 instanceof Comparable && value2 instanceof Comparable ) {
try {
final Comparable<Object> c1 = (Comparable<Object>) value1;
final Comparable<Object> c2 = (Comparable<Object>) value2;
final int result = c1.compareTo( c2 );
if ( result == 0 ) {
continue;
}
return result;
} catch ( final Exception cce ) {
// some comparables behave really weird ..
}
}
final String s1 = String.valueOf( value1 );
final String s2 = String.valueOf( value2 );
final int result = s1.compareTo( s2 );
if ( result == 0 ) {
continue;
}
return result;
}
return 0;
}
}