org.springframework.util.comparator.Comparators Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed 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
*
* https://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.springframework.util.comparator;
import java.util.Comparator;
/**
* Convenient entry point with generically typed factory methods
* for common Spring {@link Comparator} variants.
*
* @author Juergen Hoeller
* @since 5.0
*/
public abstract class Comparators {
/**
* Return a {@link Comparable} adapter.
* @see ComparableComparator#INSTANCE
*/
@SuppressWarnings("unchecked")
public static Comparator comparable() {
return ComparableComparator.INSTANCE;
}
/**
* Return a {@link Comparable} adapter which accepts
* null values and sorts them lower than non-null values.
* @see NullSafeComparator#NULLS_LOW
*/
@SuppressWarnings("unchecked")
public static Comparator nullsLow() {
return NullSafeComparator.NULLS_LOW;
}
/**
* Return a decorator for the given comparator which accepts
* null values and sorts them lower than non-null values.
* @see NullSafeComparator#NullSafeComparator(boolean)
*/
public static Comparator nullsLow(Comparator comparator) {
return new NullSafeComparator<>(comparator, true);
}
/**
* Return a {@link Comparable} adapter which accepts
* null values and sorts them higher than non-null values.
* @see NullSafeComparator#NULLS_HIGH
*/
@SuppressWarnings("unchecked")
public static Comparator nullsHigh() {
return NullSafeComparator.NULLS_HIGH;
}
/**
* Return a decorator for the given comparator which accepts
* null values and sorts them higher than non-null values.
* @see NullSafeComparator#NullSafeComparator(boolean)
*/
public static Comparator nullsHigh(Comparator comparator) {
return new NullSafeComparator<>(comparator, false);
}
}