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update experiment

This commit is contained in:
Hangga Aji Sayekti 2024-02-12 21:51:14 +07:00
parent ae5bf3ddb1
commit ae80217d4f
1 changed files with 25 additions and 23 deletions
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48
core-java-modules/core-java-uuid/src/test/java/com/baeldung/uuid/UUIDPositiveLongGeneratorUnitTest.java
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@ -1,6 +1,5 @@
package com.baeldung.uuid;
import com.fasterxml.uuid.impl.UUIDUtil;
import org.junit.jupiter.api.Test;
import java.util.UUID;
@ -9,27 +8,16 @@ import static org.assertj.core.api.Assertions.assertThat;
public class UUIDPositiveLongGeneratorUnitTest {
private void verifyUUID(UUID uuid) {
byte[] bytes = toByteArray(uuid);
// assert that byte at index 6 is 0x40 (version 4)
byte byte6 = bytes[6];
assertThat(byte6 & 0xF0).isEqualTo(0x40);
// assert that the byte at index 8 is 0x80 (IETF type variant)
byte byte8 = bytes[8];
assertThat(byte8 & 0xC0).isEqualTo(0x80);
@Test
public void whengetMostSignificantBits_thenAssertPositive() {
long randomPositiveLong = Math.abs(UUID.randomUUID().getMostSignificantBits());
assertThat(randomPositiveLong).isPositive();
}
private boolean[] getFirst122Bits(UUID uuid) {
long msb = uuid.getMostSignificantBits();
boolean[] bits = new boolean[122]; // Untuk menyimpan 122 bit pertama dari UUID
// Konversi 64 bit pertama (Most Significant Bits) menjadi bit
for (int i = 0; i < 64; i++) {
bits[i] = ((msb >> (63 - i)) & 1) == 1; // Mendapatkan nilai bit ke-i
}
return bits;
@Test
public void whengetLeastSignificantBits_thenAssertPositive() {
long randomPositiveLong = Math.abs(UUID.randomUUID().getLeastSignificantBits());
assertThat(randomPositiveLong).isPositive();
}
private byte[] toByteArray(UUID uuid) {
@ -49,10 +37,24 @@ public class UUIDPositiveLongGeneratorUnitTest {
public void whenGivenUUID_thenVerified() {
for (int i = 0; i < 100; i++) {
UUID uuid = UUID.randomUUID();
verifyUUID(uuid);
byte[] bytes = toByteArray(uuid);
long msbfirst = uuid.getMostSignificantBits() >>> 6;
System.out.println(msbfirst);
// assert that byte at index 6 is 0x40 (version 4)
byte byte6 = bytes[6];
assertThat(byte6 & 0xF0).isEqualTo(0x40);
// assert that the byte at index 8 is 0x80 (IETF type variant)
byte byte8 = bytes[8];
assertThat(byte8 & 0xC0).isEqualTo(0x80);
// 1 byte = 8 bites
int totalBites = bytes.length * 8;
// totalBites - 6 (4 bits for version and 2 bits for variant).
int randomBitsCount = totalBites - 6;
// assert that number of random bits is 122
assertThat(randomBitsCount).isEqualTo(122);
}
}