Convert shared utils exception classes and AppHelper to Kotlin (#1369)

* Convert shared utils exception classes and AppHelper

* Fix nullability issues

* Fix lint

Author: tdchow

BraintreeCore/src/main/java/com/braintreepayments/api/core/BraintreeHttpResponseParser.kt

@@ -24,7 +24,7 @@ internal class BraintreeHttpResponseParser(
         baseParser.parse(responseCode, connection)
     } catch (e: AuthorizationException) {
         val errorMessage = ErrorWithResponse(AUTH_ERROR_CODE, e.message).message
-        throw AuthorizationException(errorMessage)
+        throw AuthorizationException(errorMessage ?: "AuthorizationException with null message")
     } catch (e: UnprocessableEntityException) {
         throw ErrorWithResponse(UNPROCESSABLE_ENTITY_ERROR_CODE, e.message)
     }

BraintreeCore/src/main/java/com/braintreepayments/api/core/DeviceInspector.kt

@@ -51,7 +51,7 @@ class DeviceInspector(
      * @param context A context to access the installed packages.
      * @return boolean depending on if the Venmo app is installed, and has a valid signature.
      */
-    fun isVenmoAppSwitchAvailable(context: Context?): Boolean {
+    fun isVenmoAppSwitchAvailable(context: Context): Boolean {
         val isVenmoIntentAvailable = appHelper.isIntentAvailable(context, venmoIntent)
         val isVenmoSignatureValid = signatureVerifier.isSignatureValid(
             context, VENMO_APP_PACKAGE, VENMO_BASE_64_ENCODED_SIGNATURE
@@ -63,7 +63,7 @@ class DeviceInspector(
         return appHelper.isAppInstalled(context, PAYPAL_APP_PACKAGE)
     }
 
-    fun isVenmoInstalled(context: Context?): Boolean {
+    fun isVenmoInstalled(context: Context): Boolean {
         return appHelper.isAppInstalled(context, VENMO_APP_PACKAGE)
     }
 

SharedUtils/src/main/java/com/braintreepayments/api/sharedutils/AppHelper.java

@@ -0,0 +1,28 @@
+package com.braintreepayments.api.sharedutils
+
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import androidx.annotation.RestrictTo
+
+@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+class AppHelper {
+
+    companion object {
+        const val NO_FLAGS = 0
+    }
+
+    fun isIntentAvailable(context: Context, intent: Intent): Boolean {
+        val activities = context.packageManager.queryIntentActivities(intent, NO_FLAGS)
+        return activities.size == 1
+    }
+
+    fun isAppInstalled(context: Context, packageName: String): Boolean {
+        return try {
+            context.packageManager.getApplicationInfo(packageName, NO_FLAGS)
+            true
+        } catch (_: PackageManager.NameNotFoundException) {
+            false
+        }
+    }
+}

SharedUtils/src/main/java/com/braintreepayments/api/sharedutils/AppHelper.kt

@@ -0,0 +1,7 @@
+package com.braintreepayments.api.sharedutils
+
+/**
+ * Exception thrown when a 401 HTTP_UNAUTHORIZED response is encountered. Indicates authentication
+ * has failed in some way.
+ */
+class AuthenticationException(message: String) : Exception(message)

SharedUtils/src/main/java/com/braintreepayments/api/sharedutils/AuthenticationException.java

@@ -0,0 +1,7 @@
+package com.braintreepayments.api.sharedutils
+
+/**
+ * Exception thrown when a 403 HTTP_FORBIDDEN response is encountered. Indicates the current
+ * authorization does not have permission to make the request.
+ */
+class AuthorizationException(message: String) : Exception(message)

SharedUtils/src/main/java/com/braintreepayments/api/sharedutils/AuthenticationException.kt

@@ -0,0 +1,6 @@
+package com.braintreepayments.api.sharedutils
+
+/**
+ * Exception thrown when an HTTP request fails.
+ */
+class HttpClientException(message: String) : Exception(message)