Convert the compatibility package to Kotlin

Author: pbreault

src/main/java/com/developerphil/adbidea/compatibility/BackwardCompatibleGetter.java

@@ -0,0 +1,34 @@
+package com.developerphil.adbidea.compatibility
+
+import org.joor.ReflectException
+
+/**
+ * Abstracts the logic to call the current implementation and fall back on reflection for previous versions
+ */
+abstract class BackwardCompatibleGetter<T> {
+    fun get(): T {
+        return try {
+            getCurrentImplementation()
+        } catch (error: LinkageError) {
+            getPreviousImplementation()
+        } catch (e: Throwable) {
+            if (isReflectiveException(e)) {
+                getPreviousImplementation()
+            } else {
+                throw RuntimeException(e)
+            }
+        }
+    }
+
+    private fun isReflectiveException(t: Throwable): Boolean {
+        return t is ClassNotFoundException ||
+                t is NoSuchFieldException ||
+                t is LinkageError ||
+                t is NoSuchMethodException ||
+                t is ReflectException
+    }
+
+    abstract fun getCurrentImplementation() : T
+
+    abstract fun getPreviousImplementation() : T
+}

src/main/kotlin/com/developerphil/adbidea/compatibility/BackwardCompatibleGetter.kt

@@ -9,13 +9,13 @@ class BackwardCompatibleGetterTest {
     @Test
     fun onlyCallCurrentImplementationWhenItIsValid() {
         var value = false
-        object : BackwardCompatibleGetter<Boolean?>() {
-            override fun getCurrentImplementation(): Boolean? {
+        object : BackwardCompatibleGetter<Boolean>() {
+            override fun getCurrentImplementation(): Boolean {
                 value = true
                 return true
             }
 
-            override fun getPreviousImplementation(): Boolean? {
+            override fun getPreviousImplementation(): Boolean {
                 fail("should not be called")
                 return true
             }
@@ -34,26 +34,26 @@ class BackwardCompatibleGetterTest {
 
     @Test(expected = RuntimeException::class)
     fun throwExceptionsWhenTheyAreNotRelatedToBackwardCompatibility() {
-        object : BackwardCompatibleGetter<Boolean?>() {
-            override fun getCurrentImplementation(): Boolean? {
+        object : BackwardCompatibleGetter<Boolean>() {
+            override fun getCurrentImplementation(): Boolean {
                 throw RuntimeException("exception!")
             }
 
-            override fun getPreviousImplementation(): Boolean? {
+            override fun getPreviousImplementation(): Boolean {
                 fail("should not be called")
-                return true
+                return false
             }
         }.get()
     }
 
     private fun expectPreviousImplementationIsCalledFor(throwable: Throwable) {
         var value = false
-        object : BackwardCompatibleGetter<Boolean?>() {
-            override fun getCurrentImplementation(): Boolean? {
+        object : BackwardCompatibleGetter<Boolean>() {
+            override fun getCurrentImplementation(): Boolean {
                 throw throwable
             }
 
-            override fun getPreviousImplementation(): Boolean? {
+            override fun getPreviousImplementation(): Boolean {
                 value = true
                 return true
             }