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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.
*/
package org.apache.commons.collections.comparators;
import java.io.Serializable;
import java.util.Comparator;
/**
* A {@link Comparator Comparator} that compares
* {@link Comparable Comparable} objects.
*
* This Comparator is useful, for example,
* for enforcing the natural order in custom implementations
* of SortedSet and SortedMap.
*
* Note: In the 2.0 and 2.1 releases of Commons Collections,
* this class would throw a {@link ClassCastException} if
* either of the arguments to {@link #compare(Object, Object) compare}
* were null, not {@link Comparable Comparable},
* or for which {@link Comparable#compareTo(Object) compareTo} gave
* inconsistent results. This is no longer the case. See
* {@link #compare(Object, Object) compare} for details.
*
* @since Commons Collections 2.0
* @version $Revision$ $Date$
*
* @author Henri Yandell
*
* @see java.util.Collections#reverseOrder()
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
public class ComparableComparator implements Comparator, Serializable {
/**
* Serialization version.
*/
private static final long serialVersionUID = -291439688585137865L;
/**
* The singleton instance.
*/
private static final ComparableComparator instance = new ComparableComparator();
// -----------------------------------------------------------------------
/**
* Gets the singleton instance of a ComparableComparator.
*
* Developers are encouraged to use the comparator returned from this method
* instead of constructing a new instance to reduce allocation and GC overhead
* when multiple comparable comparators may be used in the same VM.
*
* @return the singleton ComparableComparator
*/
public static ComparableComparator getInstance() {
return instance;
}
// -----------------------------------------------------------------------
/**
* Constructor whose use should be avoided.
*
* Please use the {@link #getInstance()} method whenever possible.
*/
public ComparableComparator() {
super();
}
// -----------------------------------------------------------------------
/**
* Compare the two {@link Comparable Comparable} arguments.
* This method is equivalent to:
*
((Comparable)obj1).compareTo(obj2)
*
* @param obj1 the first object to compare
* @param obj2 the second object to compare
* @return negative if obj1 is less, positive if greater, zero if equal
* @throws NullPointerException when obj1 is null,
* or when ((Comparable)obj1).compareTo(obj2) does
* @throws ClassCastException when obj1 is not a Comparable,
* or when ((Comparable)obj1).compareTo(obj2) does
*/
public int compare(Object obj1, Object obj2) {
return ((Comparable) obj1).compareTo(obj2);
}
// -----------------------------------------------------------------------
/**
* Implement a hash code for this comparator that is consistent with
* {@link #equals(Object) equals}.
*
* @return a hash code for this comparator.
* @since Commons Collections 3.0
*/
public int hashCode() {
return "ComparableComparator".hashCode();
}
/**
* Returns true iff that Object is
* is a {@link Comparator Comparator} whose ordering is
* known to be equivalent to mine.
*
* This implementation returns true
* iff object.{@link Object#getClass() getClass()}
* equals this.getClass().
* Subclasses may want to override this behavior to remain consistent
* with the {@link Comparator#equals(Object)} contract.
*
* @param object the object to compare with
* @return true if equal
* @since Commons Collections 3.0
*/
public boolean equals(Object object) {
return (this == object) || ((null != object) && (object.getClass().equals(this.getClass())));
}
}