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* Copyright 2010, Red Hat, Inc. and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
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*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.richfaces.cdk.util;
/**
* Helper methods for comparable types
*
* @author Nick Belaevski
*/
public final class ComparatorUtils {
private ComparatorUtils() {
// private constructor
}
/**
*
* Does null-safe comparison of mutually comparable objects.
*
*
*
* Obeys common rules of {@link Comparable#compareTo(Object)} methods if both objects to compare are non-null.
*
*
*
* If one of the objects is null, but the other is not, then null object is considered to be less
* than non-null.
*
*
*
* Two null objects are considered as equal.
*
*
* @param the type of objects that this object may be compared to
* @param t1 the first object
* @param t2 the second object
* @return
*/
public static > int nullSafeCompare(T t1, T t2) {
if (t1 == null) {
return t2 == null ? 0 : -1;
} else if (t2 == null) {
return 1;
} else {
return t1.compareTo(t2);
}
}
/**
*
* Null-safe equals check. Return true if both arguments are null or equal.
*
*
* @param the type of objects to compare.
* @param t1
* @param t2
* @return true if both arguments are null or equal
*/
public static boolean nullSafeEquals(T t1, T t2) {
if (t1 == null) {
return t2 == null;
} else if (t2 == null) {
return false;
} else {
return t1.equals(t2);
}
}
}