refactor: make data centre id bits and worker id as static final
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+14
-14
@@ -29,9 +29,9 @@ import java.time.LocalDateTime;
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import java.time.ZoneId;
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/**
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* The {@code SnowflakeIdentityGenerator} generates unique identifiers using the Snowflake algorithm,
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* which combines a timestamp, worker ID, and data centre ID to create 64-bit long integers. The bit
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* distribution for the generated IDs is as follows:
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* The {@code SnowflakeIdentityGenerator} generates unique identifiers using the
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* Snowflake algorithm, which combines a timestamp, worker ID, and data centre ID to create 64-bit
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* long integers. The bit distribution for the generated IDs is as follows:
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* <ul>
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* <li>1 bit for sign</li>
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* <li>41 bits for timestamp (in milliseconds)</li>
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@@ -40,7 +40,7 @@ import java.time.ZoneId;
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* <li>12 bits for sequence number (per millisecond)</li>
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* </ul>
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* <p>
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* When initializing a {@link SnowflakeIdentityGenerator}, you must provide the worker ID and data
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* When initialising a {@link SnowflakeIdentityGenerator}, you must provide the worker ID and data
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* centre ID, ensuring they are within the valid range defined by the bit size. The generator
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* maintains an internal sequence number that increments for IDs generated within the
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* same millisecond. If the system clock moves backward, an exception is thrown to prevent
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@@ -63,15 +63,15 @@ public final class SnowflakeIdentityGenerator implements IdentityGenerator<Long>
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*/
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private final long startEpoch;
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/**
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* The number of bits reserved for the worker ID.
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*/
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private final long workerIdBits = 5L;
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/**
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* The number of bits reserved for the data centre ID.
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*/
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private final long dataCentreIdBits = 5L;
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private static final long DATA_CENTRE_ID_BITS = 5L;
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/**
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* The number of bits reserved for the worker ID.
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*/
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private static final long WORKER_ID_BITS = 5L;
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/**
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* The worker ID assigned to this generator.
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@@ -118,13 +118,13 @@ public final class SnowflakeIdentityGenerator implements IdentityGenerator<Long>
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throw new IllegalArgumentException("Start Epoch can not be greater than current timestamp!");
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}
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var maxWorkerId = ~(-1L << workerIdBits);
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var maxWorkerId = ~(-1L << WORKER_ID_BITS);
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if (workerId > maxWorkerId || workerId < 0) {
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throw new IllegalArgumentException(String.format("Worker Id can't be greater than %d or less than 0",
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maxWorkerId));
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}
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var maxDataCentreId = ~(-1L << dataCentreIdBits);
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var maxDataCentreId = ~(-1L << DATA_CENTRE_ID_BITS);
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if (dataCentreId > maxDataCentreId || dataCentreId < 0) {
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throw new IllegalArgumentException(String.format("Data Centre Id can't be greater than %d or less than 0",
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maxDataCentreId));
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@@ -172,8 +172,8 @@ public final class SnowflakeIdentityGenerator implements IdentityGenerator<Long>
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lastTimestamp = timestamp;
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// shifted and put together by or operations to form a 64-bit ID
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var timestampLeftShift = sequenceBits + workerIdBits + dataCentreIdBits;
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var dataCentreIdShift = sequenceBits + workerIdBits;
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var timestampLeftShift = sequenceBits + WORKER_ID_BITS + DATA_CENTRE_ID_BITS;
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var dataCentreIdShift = sequenceBits + WORKER_ID_BITS;
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return ((timestamp - startEpoch) << timestampLeftShift)
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| (dataCentreId << dataCentreIdShift)
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| (workerId << sequenceBits)
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