Add ByteString.isNotEmpty Kotlin extension function.

PiperOrigin-RevId: 552833973

Author: protobuf-github-bot

java/kotlin/src/main/kotlin/com/google/protobuf/ByteStrings.kt

@@ -34,15 +34,18 @@ import com.google.protobuf.ByteString
 import java.nio.ByteBuffer
 
 /** Encodes this String into a sequence of UTF-8 bytes and returns the result as a [ByteString]. */
-fun String.toByteStringUtf8(): ByteString = ByteString.copyFromUtf8(this)
-// symmetric from ByteString.toStringUtf8()
+fun String.toByteStringUtf8(): ByteString =
+  ByteString.copyFromUtf8(this) // symmetric from ByteString.toStringUtf8()
 
 /** Concatenates the given [ByteString] to this one. */
 operator fun ByteString.plus(other: ByteString): ByteString = concat(other)
 
 /** Gets the byte at [index]. */
 operator fun ByteString.get(index: Int): Byte = byteAt(index)
 
+/** Checks if this is not empty. */
+fun ByteString.isNotEmpty(): Boolean = !isEmpty()
+
 /** Returns a copy of this [ByteArray] as an immutable [ByteString]. */
 fun ByteArray.toByteString(): ByteString = ByteString.copyFrom(this)
 

java/kotlin/src/test/kotlin/com/google/protobuf/ByteStringsTest.kt

@@ -62,6 +62,16 @@ class ByteStringsTest {
     assertThat(str[2]).isEqualTo('c'.toByte())
   }
 
+  @Test
+  fun isNotEmpty_returnsTrue_whenNotEmpty() {
+    assertThat("abc".toByteStringUtf8().isNotEmpty()).isTrue()
+  }
+
+  @Test
+  fun isNotEmpty_returnsFalse_whenEmpty() {
+    assertThat(ByteString.EMPTY.isNotEmpty()).isFalse()
+  }
+
   @Test
   fun byteAtBelowZero() {
     val str = "abc".toByteStringUtf8()