io.polaris.core.hash.ArrayHash Maven / Gradle / Ivy
package io.polaris.core.hash;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.RandomAccess;
/**
* 相关文档： https://stackoverflow.com/questions/1835976/what-is-a-sensible-prime-for-hashcode-calculation
*
* @author Qt
* @since May 11, 2024
*/
public class ArrayHash {
public static int hash(Object o) {
return hash(92821, o);
}
public static int hash(Object[] o) {
return hash(92821, o);
}
public static int hash(CharSequence o) {
return hash(92821, o);
}
public static int hash(int prime, Object arg) {
if (arg == null) {
return 0;
}
if (arg instanceof Number) {
return arg.hashCode();
}
if (arg instanceof CharSequence) {
return hash(prime, (CharSequence) arg);
}
if (arg instanceof Object[]) {
return hash(prime, (Object[]) arg);
}
if (arg.getClass().isArray()) {
int h = 0;
int len = Array.getLength(arg);
for (int i = 0; i < len; i++) {
Object o = Array.get(arg, i);
h = prime * h + hash(prime, o);
}
return h;
}
if (arg instanceof Collection) {
int h = 0;
if (arg instanceof List && arg instanceof RandomAccess) {
int size = ((List) arg).size();
for (int i = 0; i < size; i++) {
Object o = ((List) arg).get(i);
h = prime * h + hash(prime, o);
}
} else {
for (Object o : ((Collection) arg)) {
h = prime * h + hash(prime, o);
}
}
return h;
}
if (arg instanceof Map) {
int h = 0;
for (Map.Entry entry : ((Map) arg).entrySet()) {
h = prime * h + (hash(prime, entry.getKey()) ^ hash(prime, entry.getValue()));
}
return h;
}
return arg.hashCode();
}
public static int hash(int prime, CharSequence str) {
int h = 0;
int len = str.length();
if (len > 0) {
for (int i = 0; i < len; i++) {
h = prime * h + str.charAt(i);
}
}
return h;
}
public static int hash(int prime, Object[] args) {
if (args == null) {
return 0;
}
int h = 0;
for (Object o : args) {
h = prime * h + hash(prime, o);
}
return h;
}
}