refactor: MLIBZ-3120, Data Requests Kotlin migration (#264)

* refactor: MLIBZ-3120, Data Requests Kotlin migration

* Merge remote-tracking branch 'origin/master' into feature/MLIBZ-3120-kotlin-data-requests

java-api-core/src/com/kinvey/java/cache/ICache.kt

@@ -133,5 +133,5 @@ interface ICache<T : GenericJson> {
      * @param q query to filter results
      * @return the array of groups containing the result of the reduce function
      */
-    fun group(aggregateType: AggregateType, fields: ArrayList<String>, reduceField: String, q: Query): Array<Aggregation.Result>
+    fun group(aggregateType: AggregateType, fields: ArrayList<String>, reduceField: String?, q: Query): Array<Aggregation.Result>
 }

java-api-core/src/com/kinvey/java/model/Aggregation.kt

@@ -26,9 +26,9 @@ import com.google.api.client.util.Key
  *
  * @author edwardf
  */
-class Aggregation(var res: List<Result>?) {
+class Aggregation(var res: List<out Result>?) {
 
-    var results: List<Result> = res ?: mutableListOf()
+    var results: List<out Result> = res ?: mutableListOf()
 
     /**
      * Return a list of result values from the aggregation

java-api-core/src/com/kinvey/java/store/BaseDataStore.kt

@@ -235,7 +235,7 @@ open class BaseDataStore<T : GenericJson> @JvmOverloads protected constructor(
      * @return items count in collection
      */
     @Throws(IOException::class)
-    fun count(cachedCallback: KinveyCachedClientCallback<Int>?): Int {
+    fun count(cachedCallback: KinveyCachedClientCallback<Int>?): Int? {
         Preconditions.checkNotNull(client, "client must not be null.")
         Preconditions.checkArgument(client.isInitialize, "client must be initialized.")
         Preconditions.checkArgument(cachedCallback == null || storeType == StoreType.CACHE, "KinveyCachedClientCallback can only be used with StoreType.CACHE")
@@ -252,7 +252,7 @@ open class BaseDataStore<T : GenericJson> @JvmOverloads protected constructor(
      * @return count of queried items in collection
      */
     @Throws(IOException::class)
-    fun count(cachedCallback: KinveyCachedClientCallback<Int>?, query: Query): Int {
+    fun count(cachedCallback: KinveyCachedClientCallback<Int>?, query: Query): Int? {
         Preconditions.checkNotNull(client, "client must not be null.")
         Preconditions.checkArgument(client.isInitialize, "client must be initialized.")
         Preconditions.checkArgument(cachedCallback == null || storeType == StoreType.CACHE, "KinveyCachedClientCallback can only be used with StoreType.CACHE")
@@ -268,7 +268,7 @@ open class BaseDataStore<T : GenericJson> @JvmOverloads protected constructor(
      * @return items count in collection on the server
      */
     @Throws(IOException::class)
-    fun countNetwork(): Int {
+    fun countNetwork(): Int? {
         Preconditions.checkNotNull(client, "client must not be null.")
         Preconditions.checkArgument(client.isInitialize, "client must be initialized.")
         return ReadCountRequest(cache, networkManager, ReadPolicy.FORCE_NETWORK, null, client.syncManager).execute()?.count ?: 0
@@ -377,7 +377,7 @@ open class BaseDataStore<T : GenericJson> @JvmOverloads protected constructor(
      * @throws IOException
      */
     @Throws(IOException::class)
-    fun delete(query: Query): Int {
+    fun delete(query: Query): Int? {
         Preconditions.checkNotNull(client, "client must not be null.")
         Preconditions.checkArgument(client.isInitialize, "client must be initialized.")
         Preconditions.checkNotNull(query, "query must not be null.")
@@ -391,7 +391,7 @@ open class BaseDataStore<T : GenericJson> @JvmOverloads protected constructor(
      * @throws IOException
      */
     @Throws(IOException::class)
-    fun delete(ids: Iterable<String>): Int {
+    fun delete(ids: Iterable<String>): Int? {
         Preconditions.checkNotNull(client, "client must not be null.")
         Preconditions.checkArgument(client.isInitialize, "client must be initialized.")
         Preconditions.checkNotNull(ids, "ids must not be null.")

java-api-core/src/com/kinvey/java/store/LinkedBaseDataStore.kt

@@ -0,0 +1,32 @@
+/*
+ *  Copyright (c) 2016, Kinvey, Inc. All rights reserved.
+ *
+ * This software is licensed to you under the Kinvey terms of service located at
+ * http://www.kinvey.com/terms-of-use. By downloading, accessing and/or using this
+ * software, you hereby accept such terms of service  (and any agreement referenced
+ * therein) and agree that you have read, understand and agree to be bound by such
+ * terms of service and are of legal age to agree to such terms with Kinvey.
+ *
+ * This software contains valuable confidential and proprietary information of
+ * KINVEY, INC and is subject to applicable licensing agreements.
+ * Unauthorized reproduction, transmission or distribution of this file and its
+ * contents is a violation of applicable laws.
+ *
+ */
+
+package com.kinvey.java.store
+
+import com.kinvey.java.AbstractClient
+import com.kinvey.java.LinkedResources.LinkedGenericJson
+import com.kinvey.java.network.LinkedNetworkManager
+
+class LinkedBaseDataStore<T : LinkedGenericJson>
+/**
+ * Constructor for creating LinkedBaseDataStore for given collection that will be mapped to itemType class
+ *
+ * @param client     Kinvey client instance to work with
+ * @param collection collection name
+ * @param itemType   class that data should be mapped to
+ * @param storeType  type of storage that client want to use
+ */
+(client: AbstractClient<*>, collection: String, itemType: Class<T>, storeType: StoreType) : BaseDataStore<T>(client, collection, itemType, storeType, LinkedNetworkManager<T>(collection, itemType, client))

java-api-core/src/com/kinvey/java/store/requests/data/save/SaveListRequest.kt

@@ -48,7 +48,7 @@ class SaveListRequest<T : GenericJson>(private val cache: ICache<T>?, private va
 
     @Throws(IOException::class)
     override fun execute(): List<T>? {
-        var ret: List<T>? = ArrayList()
+        var ret: List<T>? = mutableListOf()
         when (writePolicy) {
             WritePolicy.FORCE_LOCAL -> {
                 ret = cache?.save(objects)