add some methods

core-java-modules/core-java-uuid/src/main/java/com/baeldung/uuid/UUIDLongGenerator.java

@@ -0,0 +1,58 @@
+package com.baeldung.uuid;
+
+import java.nio.ByteBuffer;
+import java.util.UUID;
+
+public class UUIDLongGenerator {
+    public long getLeastSignificantBits(){
+        return UUID.randomUUID().getLeastSignificantBits();
+    }
+
+    public long getMostSignificantBits(){
+        return UUID.randomUUID().getMostSignificantBits();
+    }
+
+    public long gethashCode(){
+        return UUID.randomUUID().toString().hashCode();
+    }
+
+    public long combineByteBuffer(){
+        UUID uuid = UUID.randomUUID();
+        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
+        bb.putLong(uuid.getMostSignificantBits());
+        bb.putLong(uuid.getLeastSignificantBits());
+        bb.rewind(); // Kembalikan posisi buffer ke awal
+        return bb.getLong();
+    }
+
+    public long combineBitwise(){
+        UUID uniqueUUID;
+        uniqueUUID = UUID.randomUUID();
+        return (uniqueUUID.getMostSignificantBits() << 32) | (uniqueUUID.getLeastSignificantBits() & 0xFFFFFFFFL);
+    }
+
+    public long combineDirect(){
+        UUID uniqueUUID = UUID.randomUUID();
+        long mostSignificantBits = uniqueUUID.getMostSignificantBits();
+        long leastSignificantBits = uniqueUUID.getLeastSignificantBits();
+        return mostSignificantBits ^ (leastSignificantBits >> 1);
+    }
+
+    public long combinePermutation(){
+        UUID uuid = UUID.randomUUID();
+        long mostSigBits = uuid.getMostSignificantBits();
+        long leastSigBits = uuid.getLeastSignificantBits();
+        byte[] uuidBytes = new byte[16];
+
+        for (int i = 0; i < 8; i++) {
+            uuidBytes[i] = (byte) (mostSigBits >>> (8 * (7 - i)));
+            uuidBytes[i + 8] = (byte) (leastSigBits >>> (8 * (7 - i)));
+        }
+
+        long result = 0;
+        for (byte b : uuidBytes) {
+            result = (result << 8) | (b & 0xFF);
+        }
+        return result;
+    }
+}