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@fupfin
Last active March 10, 2018 15:33
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import java.util.Arrays;
public class HashCodeFunctions
{
private final static short DEFAULT_PRIME_NUMBER = 31;
private HashCodeFunctions()
{
throw new AssertionError("Could not be instantiated.");
}
public static
int hash(boolean value) { return (value ? 0 : 1); }
public static
int hash(byte value) { return value; }
public static
int hash(char value) { return value; }
public static
int hash(short value) { return value; }
public static
int hash(int value) { return value; }
public static
int hash(long value) { return ((int) (value ^ (value >> 32))); }
public static
int hash(float value) { return hash(Float.floatToIntBits(value)); }
public static
int hash(double value) { return hash(Double.doubleToLongBits(value)); }
public static
int hash(Object value) { return value.hashCode(); }
public static
int hash(boolean[] values) { return Arrays.hashCode(values); }
public static
int hash(byte[] values) { return Arrays.hashCode(values); }
public static
int hash(char[] values) { return Arrays.hashCode(values); }
public static
int hash(short[] values) { return Arrays.hashCode(values); }
public static
int hash(int[] values) { return Arrays.hashCode(values); }
public static
int hash(long[] values) { return Arrays.hashCode(values); }
public static
int hash(float[] values) { return Arrays.hashCode(values); }
public static
int hash(double[] values) { return Arrays.hashCode(values); }
public static
int hash(Object[] values) { return Arrays.hashCode(values); }
public static
int totalHash(int... hashcodes)
{
return totalHash(0, DEFAULT_PRIME_NUMBER, hashcodes);
}
public static
int totalHash(int init, short prime, int... hashcodes)
{
int result = init;
for(int hashcode: hashcodes)
result = result * prime + hashcode;
return result;
}
}
public class HashCodeTest
{
long id = 1;
int age = 30;
String name = "noname";
LocalDate birthday = LocalDate.of(1980, 1, 1);
int[] rates = {1,2,3,4};
@Override public
int hashCode()
{
return totalHash(hash(id), hash(age), hash(name), hash(birthday), hash(rates));
}
}
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