Added dateToGmt() function.

src/main/kotlin/net/thauvin/erik/akismet/Akismet.kt

@@ -39,6 +39,10 @@ import okhttp3.OkHttpClient
 import okhttp3.Request
 import okhttp3.logging.HttpLoggingInterceptor
 import java.io.IOException
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.util.Date
 import java.util.logging.Level
 import java.util.logging.Logger
 import javax.servlet.http.HttpServletRequest
@@ -423,6 +427,21 @@ open class Akismet(apiKey: String, blog: String) {
                 other = other))
     }
 
+    /**
+     * Convert a [Date][java.util.Date] to a UTC timestamp (xxxGmt parameters).
+     */
+    @JvmOverloads
+    fun dateToGmt(date: Date, zoneId: ZoneId = ZoneId.systemDefault()): String {
+        return dateToGmt(LocalDateTime.ofInstant(date.toInstant(), zoneId))
+    }
+
+    /**
+     * Convert a [LocalDateTime][java.time.LocalDateTime] to a UTC timestamp (xxxGmt parameters).
+     */
+    fun dateToGmt(date: LocalDateTime): String {
+        return date.atZone(ZoneOffset.UTC)?.toEpochSecond().toString()
+    }
+
     /**
      *
      * Execute an Akismet REST API method.

src/test/kotlin/net/thauvin/erik/akismet/AkismetTest.kt

@@ -33,6 +33,7 @@
 package net.thauvin.erik.akismet
 
 import org.mockito.Mockito
+import org.testng.Assert.assertEquals
 import org.testng.Assert.assertFalse
 import org.testng.Assert.assertTrue
 import org.testng.Assert.expectThrows
@@ -40,7 +41,11 @@ import org.testng.annotations.BeforeClass
 import org.testng.annotations.Test
 import java.io.File
 import java.io.FileInputStream
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.ZoneOffset
 import java.util.Collections
+import java.util.Date
 import java.util.Properties
 import java.util.logging.ConsoleHandler
 import java.util.logging.Level
@@ -152,5 +157,17 @@ class AkismetTest {
                                         authorUrl = authorUrl,
                                         content = content,
                                         isTest = true), "check_comment(request) -> true")
+    @Test
+    fun dateToGmtTest() {
+        val date = Date()
+        val localDateTime = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault())
+        assertEquals(
+            akismet.dateToGmt(date),
+            akismet.dateToGmt(localDateTime),
+            "dateGmt(date) == dateGmt(localDateTime)")
+        assertEquals(
+            localDateTime.atOffset(ZoneOffset.UTC).toEpochSecond(),
+            akismet.dateToGmt(date).toLong(),
+            "localDateTime = dateGmt")
     }
 }