airframe-ulid: #2106 Add ULID.ofMillis(unix time milliseconds) (#2400)

wvlet · Sep 7, 2022 · 23c1b3a · 23c1b3a
1 parent 4eab8bd
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diff --git a/airframe-ulid/src/main/scala/wvlet/airframe/ulid/ULID.scala b/airframe-ulid/src/main/scala/wvlet/airframe/ulid/ULID.scala
@@ -151,6 +151,15 @@ object ULID {
     */
   def newULIDString: String = _generator.newULIDString
 
+  /**
+    * Create a new ULID from a given unix time in milli seconds
+    * @param unixTimeMillis
+    * @return
+    */
+  def ofMillis(unixTimeMillis: Long): ULID = {
+    ULID(_generator.newULIDFromMillis(unixTimeMillis))
+  }
+
   /**
     * Create a new ULID from a given string of size 26
     */
@@ -262,10 +271,13 @@ object ULID {
       */
     def newULIDString: String = {
       val unixTimeMillis: Long = currentTimeInMillis
+      newULIDFromMillis(unixTimeMillis)
+    }
+
+    def newULIDFromMillis(unixTimeMillis: Long): String = {
       if (unixTimeMillis > MaxTime) {
         throw new IllegalStateException(f"unixtime should be less than: ${MaxTime}%,d: ${unixTimeMillis}%,d")
       }
-
       // Add a guard so that only a single-thread can generate ULID based on the previous value
       synchronized {
         val (hi, low)    = lastValue.get()

diff --git a/airframe-ulid/src/test/scala/wvlet/airframe/ulid/ULIDTest.scala b/airframe-ulid/src/test/scala/wvlet/airframe/ulid/ULIDTest.scala
@@ -116,6 +116,11 @@ class ULIDTest extends AirSpec with PropertyCheck {
     } finally {
       ULID.useDefaultULIDGenerator
     }
+  }
 
+  test("generate ULID from a given unix time") {
+    val unixTime = System.currentTimeMillis() - 10000
+    val u        = ULID.ofMillis(unixTime)
+    u.epochMillis shouldBe unixTime
   }
 }
diff --git a/docs/airframe-ulid.md b/docs/airframe-ulid.md
@@ -70,15 +70,24 @@ val ulid: ULID = ULID.newULID
 println(ulid)             // 01F3J0G1M4WQRBHGZ6HCF6JA0K
 println(ulid.epochMillis) // 1618733434500
 
+// You can generate a ULID string at ease with newULIDString
+ULID.newULIDString
+
 // Parse the string representation of ULIDs 
 val ulid2 = ULID.fromString("01F3J0G1MD4QX7Z5QB148QNH4R")
 ulid2.epochMillis // 1618733434509
 
 // Parse the binary representation of ULIDs
 ULID.fromBytes(...)
 
+
+// Create an ULID from a given unixtime (milliseconds)
+val unixTimeMillis = System.currentTimeMillis() - 1000
+ULID.ofMillis(unixTimeMillis)
+
 // Create an ULID from a given unixtime (48-bits, milliseconds) and a random value (80-bits) 
 ULID.of(unixTimeMillis, randHi, randLow)
+
 ```