Initial commit

src/main/java/space/b00tload/services/snowflake/SnowflakeIDGenerator.java

@@ -0,0 +1,73 @@
+package space.b00tload.services.snowflake;
+
+import org.slf4j.LoggerFactory;
+
+public class SnowflakeIDGenerator {
+
+    // Constants
+    private static final long EPOCH = 1704067200000L; // January 1, 2024, 00:00:00 UTC
+    private static final long MACHINE_ID_BITS = 10L;
+    private static final long SEQUENCE_BITS = 12L;
+
+    private static final long MAX_MACHINE_ID = (1L << MACHINE_ID_BITS) - 1;
+    private static final long MAX_SEQUENCE = (1L << SEQUENCE_BITS) - 1;
+
+    private static final long MACHINE_ID_SHIFT = SEQUENCE_BITS;
+    private static final long TIMESTAMP_SHIFT = SEQUENCE_BITS + MACHINE_ID_BITS;
+
+    // State
+    private final long machineId;
+    private long sequence = 0L;
+    private long lastTimestamp = -1L;
+
+    // Constructor
+    public SnowflakeIDGenerator(long machineId) {
+        if (machineId < 0 || machineId > MAX_MACHINE_ID) {
+            throw new IllegalArgumentException("Machine ID must be between 0 and " + MAX_MACHINE_ID);
+        }
+        this.machineId = machineId;
+    }
+
+    // Method to generate a new ID
+    public synchronized long generateID() {
+        long currentTimestamp = currentTimeMillis();
+
+        if (currentTimestamp < lastTimestamp) {
+            LoggerFactory.getLogger(SnowflakeIDGenerator.class).warn("Clock is moving backwards. Waiting to generate ID.");
+            while (currentTimestamp < lastTimestamp) {
+                currentTimestamp = currentTimeMillis();
+            }
+        }
+
+        if (currentTimestamp == lastTimestamp) {
+            sequence = (sequence + 1) & MAX_SEQUENCE;
+            if (sequence == 0) {
+                currentTimestamp = waitForNextTimestamp(currentTimestamp);
+            }
+        } else {
+            sequence = 0;
+        }
+
+        lastTimestamp = currentTimestamp;
+
+        return ((currentTimestamp - EPOCH) << TIMESTAMP_SHIFT)
+                | (machineId << MACHINE_ID_SHIFT)
+                | sequence;
+    }
+
+    // Get the current timestamp in milliseconds
+    private long currentTimeMillis() {
+        return System.currentTimeMillis();
+    }
+
+    // Wait for the next timestamp
+    private long waitForNextTimestamp(long currentTimestamp) {
+        long nextTimestamp = currentTimeMillis();
+        while (nextTimestamp <= currentTimestamp) {
+            nextTimestamp = currentTimeMillis();
+        }
+        return nextTimestamp;
+    }
+}
+
+

src/main/java/space/b00tload/services/snowflake/SnowflakeService.java

@@ -0,0 +1,9 @@
+package space.b00tload.services.snowflake;
+
+public class SnowflakeService {
+
+    public static void main(String[] args) {
+
+    }
+
+}