Add method to throw no null if condition is met

diff --git a/src/main/kotlin/net/pterodactylus/sone/utils/Objects.kt b/src/main/kotlin/net/pterodactylus/sone/utils/Objects.kt
index cd36ec9..2f7bd6e 100644 (file)
--- a/src/main/kotlin/net/pterodactylus/sone/utils/Objects.kt
+++ b/src/main/kotlin/net/pterodactylus/sone/utils/Objects.kt
@@ -2,3 +2,6 @@ package net.pterodactylus.sone.utils
 
 fun <T> T?.asList() = this?.let(::listOf) ?: emptyList<T>()
 val Any?.unit get() = Unit
+
+fun <T> T?.throwOnNullIf(throwCondition: Boolean, exception: () -> Throwable) =
+               if (this == null && throwCondition) throw exception() else this

diff --git a/src/test/kotlin/net/pterodactylus/sone/utils/ObjectsTest.kt b/src/test/kotlin/net/pterodactylus/sone/utils/ObjectsTest.kt
index 1c2d7f5..9e96bfe 100644 (file)
--- a/src/test/kotlin/net/pterodactylus/sone/utils/ObjectsTest.kt
+++ b/src/test/kotlin/net/pterodactylus/sone/utils/ObjectsTest.kt
@@ -1,8 +1,7 @@
 package net.pterodactylus.sone.utils
 
 import org.hamcrest.MatcherAssert.assertThat
-import org.hamcrest.Matchers.contains
-import org.hamcrest.Matchers.empty
+import org.hamcrest.Matchers.*
 import org.junit.Test
 
 /**
@@ -20,4 +19,26 @@ class ObjectsTest {
                assertThat(null.asList(), empty())
        }
 
+       @Test(expected = IllegalArgumentException::class)
+       fun `exception is thrown for null and true condition`() {
+               null.throwOnNullIf(true) { IllegalArgumentException() }
+       }
+
+       @Test
+       fun `exception is not thrown for null and false condition`() {
+               assertThat(null.throwOnNullIf(false) { IllegalArgumentException() }, nullValue())
+       }
+
+       @Test
+       fun `exception is not thrown for any and true condition`() {
+               val any = Any()
+               assertThat(any.throwOnNullIf(true) { IllegalArgumentException() }, equalTo(any))
+       }
+
+       @Test
+       fun `exception is not thrown for any and false condition`() {
+               val any = Any()
+               assertThat(any.throwOnNullIf(false) { IllegalArgumentException() }, equalTo(any))
+       }
+
 }