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com.landawn.abacus.util.Comparators Maven / Gradle / Ivy
A general programming library in Java/Android. It's easy to learn and simple to use with concise and powerful APIs.
/*
* Copyright (c) 2017, Haiyang Li.
*
* 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.landawn.abacus.util;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.function.Function;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntFunction;
import java.util.function.ToLongFunction;
import com.landawn.abacus.annotation.Beta;
import com.landawn.abacus.util.function.ToBooleanFunction;
import com.landawn.abacus.util.function.ToByteFunction;
import com.landawn.abacus.util.function.ToCharFunction;
import com.landawn.abacus.util.function.ToFloatFunction;
import com.landawn.abacus.util.function.ToShortFunction;
/**
*
* Factory utility class for Comparator.
*
* @author haiyangl
*
*/
public abstract class Comparators {
@SuppressWarnings("rawtypes")
static final Comparator NULL_FIRST_COMPARATOR = (a, b) -> a == null ? (b == null ? 0 : -1) : (b == null ? 1 : a.compareTo(b));
@SuppressWarnings("rawtypes")
static final Comparator NULL_LAST_COMPARATOR = (a, b) -> a == null ? (b == null ? 0 : 1) : (b == null ? -1 : a.compareTo(b));
@SuppressWarnings("rawtypes")
static final Comparator NATURAL_ORDER = NULL_FIRST_COMPARATOR;
@SuppressWarnings("rawtypes")
static final Comparator REVERSED_ORDER = Collections.reverseOrder(NATURAL_ORDER);
static final Comparator COMPARING_IGNORE_CASE = N::compareIgnoreCase;
static final Comparator COMPARING_BY_LENGTH = (a, b) -> (a == null ? 0 : a.length()) - (b == null ? 0 : b.length());
@SuppressWarnings("rawtypes")
static final Comparator COMPARING_BY_SIZE = (a, b) -> (a == null ? 0 : a.size()) - (b == null ? 0 : b.size());
@SuppressWarnings("rawtypes")
static final Comparator COMPARING_BY_MAP_SIZE = (a, b) -> (a == null ? 0 : a.size()) - (b == null ? 0 : b.size());
Comparators() {
// Singleton
}
public static final Comparator BOOLEAN_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator CHAR_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] > b[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator BYTE_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] > b[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator SHORT_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] > b[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator INT_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] > b[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator LONG_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
if (a[i] != b[i]) {
return a[i] > b[i] ? 1 : -1;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator FLOAT_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
int result = 0;
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
result = Float.compare(a[i], b[i]);
if (result != 0) {
return result;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator DOUBLE_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
int result = 0;
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
result = Double.compare(a[i], b[i]);
if (result != 0) {
return result;
}
}
return N.compare(lenA, lenB);
};
public static final Comparator OBJECT_ARRAY_COMPARATOR = (a, b) -> {
final int lenA = N.len(a);
final int lenB = N.len(b);
int result = 0;
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
result = NATURAL_ORDER.compare(a[i], b[i]);
if (result != 0) {
return result;
}
}
return N.compare(lenA, lenB);
};
@SuppressWarnings("rawtypes")
public static final Comparator COLLECTION_COMPARATOR = (a, b) -> {
if (N.isNullOrEmpty(a)) {
return N.isNullOrEmpty(b) ? 0 : -1;
} else if (N.isNullOrEmpty(b)) {
return 1;
}
final Iterator iterA = a.iterator();
final Iterator iterB = b.iterator();
final int lenA = N.size(a);
final int lenB = N.size(b);
int result = 0;
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
result = NATURAL_ORDER.compare(iterA.next(), iterB.next());
if (result != 0) {
return result;
}
}
return N.compare(lenA, lenB);
};
/**
* Same as {@code nullsFirst}
* @param
* @return
* {@link #nullsFirst()}
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static Comparator naturalOrder() {
return NATURAL_ORDER;
}
/**
*
* @param
* @return
*/
@SuppressWarnings("rawtypes")
public static Comparator reversedOrder() {
return REVERSED_ORDER;
}
/**
*
* @param
* @param cmp
* @return
*/
public static Comparator reversedOrder(final Comparator cmp) {
if (cmp == null || cmp == NATURAL_ORDER) {
return REVERSED_ORDER;
} else if (cmp == REVERSED_ORDER) {
return NATURAL_ORDER;
}
return Collections.reverseOrder(cmp);
}
/**
*
* @param
* @return
*/
@SuppressWarnings("rawtypes")
public static Comparator nullsFirst() {
return (Comparator) NULL_FIRST_COMPARATOR;
}
/**
*
* @param
* @param cmp
* @return
*/
public static Comparator nullsFirst(final Comparator cmp) {
if (cmp == null || cmp == NULL_FIRST_COMPARATOR) {
return (Comparator) NULL_FIRST_COMPARATOR;
}
return (a, b) -> a == null ? (b == null ? 0 : -1) : (b == null ? 1 : cmp.compare(a, b));
}
@SuppressWarnings("rawtypes")
private static final Comparator NULLS_FIRST_OR_ELSE_EQUAL = (a, b) -> a == null ? (b == null ? 0 : -1) : (b == null ? 1 : 0);
/**
*
* @param
* @return
*/
@Beta
public static Comparator nullsFirstOrElseEqual() {
return NULLS_FIRST_OR_ELSE_EQUAL;
}
/**
*
* @param
* @return
*/
@SuppressWarnings("rawtypes")
public static Comparator nullsLast() {
return (Comparator) NULL_LAST_COMPARATOR;
}
/**
*
* @param
* @param cmp
* @return
*/
public static Comparator nullsLast(final Comparator cmp) {
if (cmp == null || cmp == NULL_LAST_COMPARATOR) {
return (Comparator) NULL_LAST_COMPARATOR;
}
return (a, b) -> a == null ? (b == null ? 0 : 1) : (b == null ? -1 : cmp.compare(a, b));
}
@SuppressWarnings("rawtypes")
private static final Comparator NULLS_LAST_OR_ELSE_EQUAL = (a, b) -> a == null ? (b == null ? 0 : 1) : (b == null ? -1 : 0);
/**
*
* @param
* @return
*/
@Beta
public static Comparator nullsLastOrElseEqual() {
return NULLS_LAST_OR_ELSE_EQUAL;
}
/**
*
* @param
* @param
* @param keyMapper
* @return
*/
public static > Comparator comparingBy(final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> N.compare(keyMapper.apply(a), keyMapper.apply(b));
}
/**
*
* @param
* @param
* @param keyMapper
* @return
*/
@Beta
public static > Comparator comparingByIfNotNullOrElseNullsFirst(final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> a == null ? (b == null ? 0 : -1) : (b == null ? 1 : N.compare(keyMapper.apply(a), keyMapper.apply(b)));
}
/**
*
* @param
* @param
* @param keyMapper
* @return
*/
@Beta
public static > Comparator comparingByIfNotNullOrElseNullsLast(final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> a == null ? (b == null ? 0 : 1) : (b == null ? -1 : N.compare(keyMapper.apply(a), keyMapper.apply(b)));
}
/**
* Reversed comparing by.
*
* @param
* @param
* @param keyMapper
* @return
*/
public static > Comparator reversedComparingBy(final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> N.compare(keyMapper.apply(b), keyMapper.apply(a));
}
/**
*
* @param
* @param
* @param keyMapper
* @return
*/
@Beta
public static > Comparator reversedComparingByIfNotNullOrElseNullsFirst(
final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> a == null ? (b == null ? 0 : -1) : (b == null ? 1 : N.compare(keyMapper.apply(b), keyMapper.apply(a)));
}
/**
*
* @param
* @param
* @param keyMapper
* @return
*/
@Beta
public static > Comparator reversedComparingByIfNotNullOrElseNullsLast(
final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> a == null ? (b == null ? 0 : 1) : (b == null ? -1 : N.compare(keyMapper.apply(b), keyMapper.apply(a)));
}
/**
*
* @param
* @param
* @param keyMapper
* @param keyComparator
* @return
*/
public static Comparator comparingBy(final Function keyMapper, final Comparator keyComparator) {
N.checkArgNotNull(keyMapper);
N.checkArgNotNull(keyComparator);
return (a, b) -> keyComparator.compare(keyMapper.apply(a), keyMapper.apply(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingBoolean(final ToBooleanFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Boolean.compare(keyMapper.applyAsBoolean(a), keyMapper.applyAsBoolean(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingChar(final ToCharFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Character.compare(keyMapper.applyAsChar(a), keyMapper.applyAsChar(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingByte(final ToByteFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Byte.compare(keyMapper.applyAsByte(a), keyMapper.applyAsByte(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingShort(final ToShortFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Short.compare(keyMapper.applyAsShort(a), keyMapper.applyAsShort(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingInt(final ToIntFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Integer.compare(keyMapper.applyAsInt(a), keyMapper.applyAsInt(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingLong(final ToLongFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Long.compare(keyMapper.applyAsLong(a), keyMapper.applyAsLong(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingFloat(final ToFloatFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Float.compare(keyMapper.applyAsFloat(a), keyMapper.applyAsFloat(b));
}
/**
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingDouble(final ToDoubleFunction keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> Double.compare(keyMapper.applyAsDouble(a), keyMapper.applyAsDouble(b));
}
/**
* Comparing ignore case.
*
* @return
*/
public static Comparator comparingIgnoreCase() {
return COMPARING_IGNORE_CASE;
}
/**
* Comparing ignore case.
*
* @param
* @param keyMapper
* @return
*/
public static Comparator comparingIgnoreCase(final Function keyMapper) {
N.checkArgNotNull(keyMapper);
return (a, b) -> N.compareIgnoreCase(keyMapper.apply(a), keyMapper.apply(b));
}
/**
* Comparing by key.
*
* @param the key type
* @param the value type
* @return
*/
public static , V> Comparator> comparingByKey() {
return (a, b) -> N.compare(a.getKey(), b.getKey());
}
/**
* Reversed comparing by key.
*
* @param the key type
* @param the value type
* @return
*/
public static , V> Comparator> reversedComparingByKey() {
return (a, b) -> N.compare(b.getKey(), a.getKey());
}
/**
* Comparing by value.
*
* @param the key type
* @param the value type
* @return
*/
public static > Comparator> comparingByValue() {
return (a, b) -> N.compare(a.getValue(), b.getValue());
}
/**
* Reversed comparing by value.
*
* @param the key type
* @param the value type
* @return
*/
public static > Comparator> reversedComparingByValue() {
return (a, b) -> N.compare(b.getValue(), a.getValue());
}
/**
* Comparing by key.
*
* @param the key type
* @param the value type
* @param cmp
* @return
*/
public static Comparator> comparingByKey(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> cmp.compare(a.getKey(), b.getKey());
}
/**
* Comparing by value.
*
* @param the key type
* @param the value type
* @param cmp
* @return
*/
public static Comparator> comparingByValue(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> cmp.compare(a.getValue(), b.getValue());
}
/**
* Reversed comparing by key.
*
* @param the key type
* @param the value type
* @param cmp
* @return
*/
@Beta
public static Comparator> reversedComparingByKey(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> cmp.compare(b.getKey(), a.getKey());
}
/**
* Reversed comparing by value.
*
* @param the key type
* @param the value type
* @param cmp
* @return
*/
@Beta
public static Comparator> reversedComparingByValue(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> cmp.compare(b.getValue(), a.getValue());
}
/**
* Comparing by length.
*
* @param
* @return
*/
public static Comparator comparingByLength() {
return (Comparator) COMPARING_BY_LENGTH;
}
/**
* Comparing by size.
*
* @param
* @return
*/
@SuppressWarnings("rawtypes")
public static Comparator comparingBySize() {
return (Comparator) COMPARING_BY_SIZE;
}
/**
* Comparing by sizee.
*
* @param
* @return
*/
@SuppressWarnings("rawtypes")
public static Comparator comparingByMapSize() {
return (Comparator) COMPARING_BY_MAP_SIZE;
}
public static Comparator comparingArray(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> {
if (N.isNullOrEmpty(a)) {
return N.isNullOrEmpty(b) ? 0 : -1;
} else if (N.isNullOrEmpty(b)) {
return 1;
}
final int lenA = N.len(a);
final int lenB = N.len(b);
int result = 0;
for (int i = 0, minLen = N.min(lenA, lenB); i < minLen; i++) {
result = cmp.compare(a[i], b[i]);
if (result != 0) {
return result;
}
}
return N.compare(lenA, lenB);
};
}
public static > Comparator comparingCollection(final Comparator cmp) {
N.checkArgNotNull(cmp);
return (a, b) -> {
if (N.isNullOrEmpty(a)) {
return N.isNullOrEmpty(b) ? 0 : -1;
} else if (N.isNullOrEmpty(b)) {
return 1;
}
final Iterator iterA = a.iterator();
final Iterator iterB = b.iterator();
final int sizeA = N.size(a);
final int sizeB = N.size(b);
int result = 0;
for (int i = 0, minLen = N.min(sizeA, sizeB); i < minLen; i++) {
result = cmp.compare(iterA.next(), iterB.next());
if (result != 0) {
return result;
}
}
return N.compare(sizeA, sizeB);
};
}
}
