com.hazelcast.query.impl.Comparables Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021, Hazelcast, Inc. All Rights Reserved.
*
* 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
*
* 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 com.hazelcast.query.impl;
import java.util.Comparator;
/**
* Provides utilities which compare and canonicalize {@link Comparable}
* instances.
*/
public final class Comparables {
/**
* Provides the same comparison logic as {@link #compare} does, but in a
* form of a {@link Comparator}.
*/
public static final Comparator COMPARATOR = Comparables::compare;
private Comparables() {
}
/**
* Checks the provided {@link Comparable} instances for equality.
*
* Special numeric comparison logic is used for {@link Double}, {@link Long},
* {@link Float}, {@link Integer}, {@link Short} and {@link Byte}. See
* {@link Numbers#equal(Number, Number)} for more details.
*
* @param lhs the left-hand side {@link Comparable}. Can't be {@code null}.
* @param rhs the right-hand side {@link Comparable}. May be {@code null}.
* @return {@code true} if the provided comparables are equal, {@code false}
* otherwise.
*/
public static boolean equal(Comparable lhs, Comparable rhs) {
assert lhs != null;
if (rhs == null) {
return false;
}
if (lhs.getClass() == rhs.getClass()) {
return lhs.equals(rhs);
}
if (lhs instanceof Number && rhs instanceof Number) {
return Numbers.equal((Number) lhs, (Number) rhs);
}
return lhs.equals(rhs);
}
/**
* Compares the provided {@link Comparable} instances.
*
* Special numeric comparison logic is used for {@link Double}, {@link Long},
* {@link Float}, {@link Integer}, {@link Short} and {@link Byte}. See
* {@link Numbers#compare(Comparable, Comparable)} for more details.
*
* @param lhs the left-hand side {@link Comparable}. Can't be {@code null}.
* @param rhs the right-hand side {@link Comparable}. Can't be {@code null}.
* @return a negative integer, zero, or a positive integer as the left-hand
* side {@link Comparable} is less than, equal to, or greater than the
* right-hand side {@link Comparable}.
*/
@SuppressWarnings("unchecked")
public static int compare(Comparable lhs, Comparable rhs) {
assert lhs != null;
assert rhs != null;
if (lhs.getClass() == rhs.getClass()) {
return lhs.compareTo(rhs);
}
if (lhs instanceof Number && rhs instanceof Number) {
return Numbers.compare(lhs, rhs);
}
return lhs.compareTo(rhs);
}
/**
* Canonicalizes the given {@link Comparable} value for the purpose of a
* hash-based lookup.
*
* Special numeric canonicalization logic is used for {@link Double},
* {@link Long}, {@link Float}, {@link Integer}, {@link Short} and
* {@link Byte}. See {@link Numbers#canonicalizeForHashLookup} for more
* details.
*
* @param value the {@link Comparable} to canonicalize.
* @return a canonical representation of the given {@link Comparable} or
* the original {@link Comparable} if there is no special canonical
* representation for it.
*/
public static Comparable canonicalizeForHashLookup(Comparable value) {
if (value instanceof Number) {
return Numbers.canonicalizeForHashLookup(value);
}
return value;
}
}