DATACOUCH-341 - Add kotlin extension functions

Motivation
----------
Add kotin extension methods to couchbase and reactive couchbase
operations as required.

Changes
-------
Extensions leveraging reified type has been added.

Results
-------
It is now possible to use reified types rather than passing the java
class reference to some operation functions.

Original pull request: #160.

pom.xml

@@ -165,6 +165,20 @@
             <scope>test</scope>
         </dependency>
 
+        <!-- Kotlin extension -->
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib</artifactId>
+            <version>${kotlin}</version>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test</artifactId>
+            <version>${kotlin}</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <repositories>

src/integration/kotlin/org/springframework/data/couchbase/core/CouchbaseOperationsExtensionsTest.kt

@@ -0,0 +1,32 @@
+package org.springframework.data.couchbase.core
+
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.data.annotation.Id
+import org.springframework.data.couchbase.ContainerResourceRunner
+import org.springframework.data.couchbase.IntegrationTestApplicationConfig
+import org.springframework.test.context.ContextConfiguration
+import kotlin.test.assertEquals
+
+@RunWith(ContainerResourceRunner::class)
+@ContextConfiguration(classes = [IntegrationTestApplicationConfig::class])
+class CouchbaseOperationsExtensionsTest {
+
+    @Autowired
+    lateinit var template: CouchbaseTemplate
+
+    @Test
+    fun `findById should call the reified extension`()  {
+        val entityId = "CouchbaseOperationsExtensionsTestFindById"
+        val entity = Entity(entityId)
+        template.save(entity)
+        val stored = template.findById<Entity>(entityId)
+        assertEquals(entity.id, stored.id)
+    }
+
+    class Entity constructor(id: String) {
+        @Id
+        var id = id
+    }
+}

src/integration/kotlin/org/springframework/data/couchbase/core/RxJavaCouchbaseOperationsExtensionsTest.kt

@@ -0,0 +1,35 @@
+package org.springframework.data.couchbase.core
+
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.data.annotation.Id
+import org.springframework.data.couchbase.ContainerResourceRunner
+import org.springframework.data.couchbase.ReactiveIntegrationTestApplicationConfig
+import org.springframework.data.couchbase.core.query.N1qlSecondaryIndexed
+import org.springframework.test.context.ContextConfiguration
+import kotlin.test.assertEquals
+
+
+@RunWith(ContainerResourceRunner::class)
+@ContextConfiguration(classes = [ReactiveIntegrationTestApplicationConfig::class])
+class RxJavaCouchbaseOperationsExtensionsTest {
+
+    @Autowired
+    lateinit var template: RxJavaCouchbaseTemplate
+
+    @Test
+    fun `findById should call the reified extension`()  {
+        val entityId = "RxJavaCouchbaseOperationsExtensionsTestFindById"
+        val entity = Entity(entityId)
+        template.save(entity).toBlocking().single()
+        val stored = template.findById<Entity>(entityId).toBlocking().single()
+        assertEquals(entity.id, stored.id)
+    }
+
+    class Entity constructor(id: String) {
+        @Id
+        var id = id
+    }
+}
+

src/main/kotlin/org/springframework/data/couchbase/core/CouchbaseOperationsExtensions.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2018 the original author or authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.data.couchbase.core
+
+import com.couchbase.client.java.query.N1qlQuery
+import com.couchbase.client.java.view.SpatialViewQuery
+import com.couchbase.client.java.view.ViewQuery
+
+/**
+ * Kotlin extensions for [CouchbaseOperations]
+ *
+ * @author Subhashni Balakrishnan
+ */
+
+/**
+ * Extension for [CouchbaseOperations.findById] leveraging reified type
+ * @param id the identifier of the document.
+ * @return the document fetched from couchbase.
+ */
+inline fun <reified T: Any> CouchbaseOperations.findById(id: String) : T =
+    findById(id, T::class.java)
+
+/**
+ * Extension for [CouchbaseOperations.findByView] leveraging reified type.
+ * @param query a [ViewQuery] instance that defines the query.
+ * @return list of entities satisfying the view query.
+ */
+inline fun <reified T: Any> CouchbaseOperations.findByView(query: ViewQuery) : List<T> =
+    findByView(query, T::class.java)
+
+/**
+ * Extension for [CouchbaseOperations.findBySpatialView] leveraging reified type.
+ * @param query a [SpatialViewQuery] instance that defines the query.
+ * @return list of entities satisfying the spatial view query.
+ */
+inline fun <reified T: Any> CouchbaseOperations.findBySpatialView(query: SpatialViewQuery) : List<T> =
+    findBySpatialView(query, T::class.java)
+
+/**
+ * Extension for [CouchbaseOperations.findByN1QL] leveraging reified type.
+ * @param query a [N1qlQuery] instance that defines the query.
+ * @return list of entities satisfying the N1ql query.
+ */
+inline fun <reified T: Any> CouchbaseOperations.findByN1QL(query: N1qlQuery) : List<T> =
+    findByN1QL(query, T::class.java)
+
+/**
+ * Extension for [CouchbaseOperations.findByN1QLProjection] leveraging reified type.
+ * @param query a [N1qlQuery] instance that defines the query.
+ * @return list of entities satisfying the N1ql query projection.
+ */
+inline fun <reified T: Any> CouchbaseOperations.findByN1QLProjection(query: N1qlQuery) : List<T> =
+    findByN1QLProjection(query, T::class.java)

src/main/kotlin/org/springframework/data/couchbase/core/RxJavaCouchbaseOperationsExtensions.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2018 the original author or authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.data.couchbase.core
+
+import com.couchbase.client.java.query.N1qlQuery
+import com.couchbase.client.java.view.SpatialViewQuery
+import com.couchbase.client.java.view.ViewQuery
+import rx.Observable
+
+/**
+ * Kotlin extensions for [RxJavaCouchbaseOperations]
+ *
+ * @author Subhashni Balakrishnan
+ */
+
+/**
+ * Extension for [RxJavaCouchbaseOperations.findById] leveraging reified type
+ * @param id the identifier of the document.
+ * @return the document fetched from couchbase.
+ */
+inline fun <reified T: Any> RxJavaCouchbaseOperations.findById(id: String) : Observable<T> =
+        findById(id, T::class.java)
+
+/**
+ * Extension for [RxJavaCouchbaseOperations.findByView] leveraging reified type.
+ * @param query a [ViewQuery] instance that defines the query.
+ * @return list of entities satisfying the view query.
+ */
+inline fun <reified T: Any> RxJavaCouchbaseOperations.findByView(query: ViewQuery) : Observable<T> =
+        findByView(query, T::class.java)
+
+/**
+ * Extension for [RxJavaCouchbaseOperations.findBySpatialView] leveraging reified type.
+ * @param query a [SpatialViewQuery] instance that defines the query.
+ * @return list of entities satisfying the spatial view query.
+ */
+inline fun <reified T: Any> RxJavaCouchbaseOperations.findBySpatialView(query: SpatialViewQuery) : Observable<T> =
+        findBySpatialView(query, T::class.java)
+
+/**
+ * Extension for [RxJavaCouchbaseOperations.findByN1QL] leveraging reified type.
+ * @param query a [N1qlQuery] instance that defines the query.
+ * @return list of entities satisfying the n1ql query.
+ */
+inline fun <reified T: Any> RxJavaCouchbaseOperations.findByN1QL(query: N1qlQuery) : Observable<T> =
+        findByN1QL(query, T::class.java)
+
+/**
+ * Extension for [RxJavaCouchbaseOperations.findByN1QLProjection] leveraging reified type.
+ * @param query a [N1qlQuery] instance that defines the query.
+ * @return list of entities satisfying the n1ql query projection.
+ */
+inline fun <reified T: Any> RxJavaCouchbaseOperations.findByN1QLProjection(query: N1qlQuery) : Observable<T> =
+        findByN1QLProjection(query, T::class.java)