spark ArrayWrappers 源码
spark ArrayWrappers 代码
文件路径:/common/kvstore/src/main/java/org/apache/spark/util/kvstore/ArrayWrappers.java
/*
* 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.spark.util.kvstore;
import java.util.Arrays;
import com.google.common.base.Preconditions;
/**
* A factory for array wrappers so that arrays can be used as keys in a map, sorted or not.
*
* The comparator implementation makes two assumptions:
* - All elements are instances of Comparable
* - When comparing two arrays, they both contain elements of the same type in corresponding
* indices.
*
* Otherwise, ClassCastExceptions may occur. The equality method can compare any two arrays.
*
* This class is not efficient and is mostly meant to compare really small arrays, like those
* generally used as indices and keys in a KVStore.
*/
class ArrayWrappers {
@SuppressWarnings("unchecked")
public static Comparable<Object> forArray(Object a) {
Preconditions.checkArgument(a.getClass().isArray());
Comparable<?> ret;
if (a instanceof int[]) {
ret = new ComparableIntArray((int[]) a);
} else if (a instanceof long[]) {
ret = new ComparableLongArray((long[]) a);
} else if (a instanceof byte[]) {
ret = new ComparableByteArray((byte[]) a);
} else {
Preconditions.checkArgument(!a.getClass().getComponentType().isPrimitive());
ret = new ComparableObjectArray((Object[]) a);
}
return (Comparable<Object>) ret;
}
private static class ComparableIntArray implements Comparable<ComparableIntArray> {
private final int[] array;
ComparableIntArray(int[] array) {
this.array = array;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ComparableIntArray)) {
return false;
}
return Arrays.equals(array, ((ComparableIntArray) other).array);
}
@Override
public int hashCode() {
int code = 0;
for (int j : array) {
code = (code * 31) + j;
}
return code;
}
@Override
public int compareTo(ComparableIntArray other) {
int len = Math.min(array.length, other.array.length);
for (int i = 0; i < len; i++) {
int diff = array[i] - other.array[i];
if (diff != 0) {
return diff;
}
}
return array.length - other.array.length;
}
}
private static class ComparableLongArray implements Comparable<ComparableLongArray> {
private final long[] array;
ComparableLongArray(long[] array) {
this.array = array;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ComparableLongArray)) {
return false;
}
return Arrays.equals(array, ((ComparableLongArray) other).array);
}
@Override
public int hashCode() {
int code = 0;
for (long l : array) {
code = (code * 31) + (int) l;
}
return code;
}
@Override
public int compareTo(ComparableLongArray other) {
int len = Math.min(array.length, other.array.length);
for (int i = 0; i < len; i++) {
long diff = array[i] - other.array[i];
if (diff != 0) {
return diff > 0 ? 1 : -1;
}
}
return array.length - other.array.length;
}
}
private static class ComparableByteArray implements Comparable<ComparableByteArray> {
private final byte[] array;
ComparableByteArray(byte[] array) {
this.array = array;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ComparableByteArray)) {
return false;
}
return Arrays.equals(array, ((ComparableByteArray) other).array);
}
@Override
public int hashCode() {
int code = 0;
for (byte b : array) {
code = (code * 31) + b;
}
return code;
}
@Override
public int compareTo(ComparableByteArray other) {
int len = Math.min(array.length, other.array.length);
for (int i = 0; i < len; i++) {
int diff = array[i] - other.array[i];
if (diff != 0) {
return diff;
}
}
return array.length - other.array.length;
}
}
private static class ComparableObjectArray implements Comparable<ComparableObjectArray> {
private final Object[] array;
ComparableObjectArray(Object[] array) {
this.array = array;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ComparableObjectArray)) {
return false;
}
return Arrays.equals(array, ((ComparableObjectArray) other).array);
}
@Override
public int hashCode() {
int code = 0;
for (Object o : array) {
code = (code * 31) + o.hashCode();
}
return code;
}
@Override
@SuppressWarnings("unchecked")
public int compareTo(ComparableObjectArray other) {
int len = Math.min(array.length, other.array.length);
for (int i = 0; i < len; i++) {
int diff = ((Comparable<Object>) array[i]).compareTo(other.array[i]);
if (diff != 0) {
return diff;
}
}
return array.length - other.array.length;
}
}
}
相关信息
相关文章
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦