Remove generics from Backend interface

criteria/common/src/org/immutables/criteria/internal/Backend.java

@@ -20,25 +20,25 @@
 
 /**
  * Abstraction of a asynchronous service used by adapters and modeled as a single abstract method (SAM).
- *
- * @param <T> type of the result (computation)
  */
-public interface Backend<T> {
+public interface Backend {
 
   /**
    * Apply an operation on the back-end. {@code operation} in this context can mean query / update
    * / insert  / index etc.
    *
+   * <p>Produced publisher can represent empty, single, multiple or unbounded event flow.
+   *
    * @param operation operation to be performed on the back-end.
-   * @return empty or unbounded flow of events (can also be a single response)
+   * @return empty, single, multiple or unbounded event flow
    */
-  Publisher<T> execute(Operation operation);
+  <T> Publisher<T> execute(Operation<T> operation);
 
   /**
    * Generic operation to be executed on the back-end. Typical operations include
    * query, update, delete etc.
    */
-  interface Operation {
+  interface Operation<T> {
 
   }
 

criteria/common/src/org/immutables/criteria/internal/InternalReader.java

@@ -28,13 +28,13 @@
 public class InternalReader<T> implements Repository.Reader<T> {
 
   private final ImmutableQuery query;
-  private final Backend<T> backend;
+  private final Backend backend;
 
-  public InternalReader(DocumentCriteria<T> criteria, Backend<T> backend) {
+  public InternalReader(DocumentCriteria<T> criteria, Backend backend) {
     this(ImmutableQuery.of(criteria), backend);
   }
 
-  private InternalReader(ImmutableQuery query, Backend<T> backend) {
+  private InternalReader(ImmutableQuery query, Backend backend) {
     this.query = Objects.requireNonNull(query, "query");
     this.backend = Objects.requireNonNull(backend, "backend");
   }

criteria/common/src/org/immutables/criteria/internal/Query.java

@@ -25,10 +25,10 @@
  * Query sent to a backend
  */
 @Value.Immutable
-public interface Query extends Backend.Operation {
+public interface Query<T> extends Backend.Operation<T> {
 
   @Value.Parameter
-  DocumentCriteria<?> criteria();
+  DocumentCriteria<T> criteria();
 
   OptionalLong limit();
 

criteria/elasticsearch/src/org/immutables/criteria/elasticsearch/ElasticBackend.java

@@ -43,43 +43,42 @@
 
 /**
  * Queries <a href="https://www.elastic.co/">ElasticSearch</a> data-store.
- * @param <T>
  */
-public class ElasticBackend<T> implements Backend<T> {
+public class ElasticBackend implements Backend {
 
   private final RestClient restClient;
   private final ObjectMapper mapper;
-  private final Class<T> type;
+  private final Class<?> type;
   private final String index;
 
   public ElasticBackend(RestClient restClient,
-                        Class<T> type,
                         ObjectMapper mapper,
+                        Class<?> type,
                         String index) {
     this.restClient = Objects.requireNonNull(restClient, "restClient");
-    this.type = Objects.requireNonNull(type, "type");
     this.mapper = Objects.requireNonNull(mapper, "mapper");
+    this.type = type;
     this.index = Objects.requireNonNull(index, "index");
   }
 
   @Override
-  public Publisher<T> execute(Operation query) {
+  public <T> Publisher<T> execute(Operation<T> query) {
     Objects.requireNonNull(query, "query");
 
-    return queryInternal((Query) query);
+    return queryInternal((Query<T>) query);
   }
 
-  private Publisher<T> queryInternal(Query query) {
+  private <T> Publisher<T> queryInternal(Query<T> query) {
     final Request request = new Request("POST", String.format("/%s/_search", index));
     final Expression expression = Criterias.toExpression(query.criteria());
     final ObjectNode json = Elasticsearch.converter(mapper).convert(expression);
     query.limit().ifPresent(limit -> json.put("size", limit));
     query.offset().ifPresent(offset -> json.put("start", offset));
     request.setEntity(new StringEntity(json.toString(), ContentType.APPLICATION_JSON));
-    return Reactive.flatMapIterable(Reactive.map(new AsyncRestPublisher(restClient, request), converter()), x -> x);
+    return Reactive.flatMapIterable(Reactive.map(new AsyncRestPublisher(restClient, request), converter((Class<T>) type)), x -> x);
   }
 
-  private Function<Response, List<T>> converter() {
+  private <T> Function<Response, List<T>> converter(Class<T> type) {
     return response -> {
       try (InputStream is = response.getEntity().getContent()) {
         final ObjectNode root = mapper.readValue(is, ObjectNode.class);

criteria/elasticsearch/test/org/immutables/criteria/elasticsearch/ElasticsearchIntegrationTest.java

@@ -45,7 +45,7 @@ public class ElasticsearchIntegrationTest {
 
   private static final String INDEX_NAME = "mymodel";
 
-  private ElasticBackend<ElasticModel> backend;
+  private ElasticBackend backend;
   private ElasticModelRepository repository;
 
   @BeforeClass
@@ -78,7 +78,7 @@ public static void setupElastic() throws Exception {
 
   @Before
   public void setupRepository() throws Exception {
-    this.backend = new ElasticBackend<>(RESOURCE.restClient(),  ElasticModel.class, MAPPER, INDEX_NAME);
+    this.backend = new ElasticBackend(RESOURCE.restClient(),  MAPPER, ElasticModel.class, INDEX_NAME);
     this.repository = new ElasticModelRepository(backend);
   }
 

criteria/geode/src/org/immutables/criteria/geode/GeodeBackend.java

@@ -23,7 +23,7 @@
 
 import java.util.Objects;
 
-public class GeodeBackend<T> implements Backend<T> {
+public class GeodeBackend<T> implements Backend {
 
   private final Region<?, ?> region;
 
@@ -32,7 +32,7 @@ public GeodeBackend(Region<?, ?> region) {
   }
 
   @Override
-  public Publisher<T> execute(Operation query) {
+  public <T> Publisher<T> execute(Operation<T> query) {
     throw new UnsupportedOperationException();
   }
 

criteria/mongo/src/org/immutables/criteria/mongo/MongoBackend.java

@@ -17,7 +17,6 @@
 package org.immutables.criteria.mongo;
 
 import com.mongodb.reactivestreams.client.MongoCollection;
-import com.mongodb.reactivestreams.client.Success;
 import org.bson.conversions.Bson;
 import org.immutables.criteria.Criterias;
 import org.immutables.criteria.internal.Backend;
@@ -31,21 +30,18 @@
  *
  * <p>Based on <a href="https://mongodb.github.io/mongo-java-driver-reactivestreams/">Mongo reactive streams driver</a>
  */
-class MongoBackend<T> implements Backend<T> {
+class MongoBackend implements Backend {
 
-  private final MongoCollection<T> collection;
+  private final MongoCollection<?> collection;
 
-  MongoBackend(MongoCollection<T> collection) {
+  MongoBackend(MongoCollection<?> collection) {
     this.collection = Objects.requireNonNull(collection, "collection");
   }
 
-  // which one is _id ?
-  public Publisher<Success> insert(T entity) {
-    return collection.insertOne(entity);
-  }
-
   @Override
-  public Publisher<T> execute(Operation operation) {
+  public <T> Publisher<T> execute(Operation<T> operation) {
+    @SuppressWarnings("unchecked")
+    final MongoCollection<T> collection = (MongoCollection<T>) this.collection;
     final Bson filter = Mongos.converter(collection.getCodecRegistry()).convert(Criterias.toExpression(((Query) operation).criteria()));
     return collection.find(filter);
   }

criteria/mongo/test/org/immutables/criteria/mongo/MongoRepositoryTest.java

@@ -49,7 +49,7 @@ public class MongoRepositoryTest {
 
   private MongoCollection<Person> collection;
 
-  private MongoBackend<Person> backend;
+  private MongoBackend backend;
   private PersonRepository repository;
 
   @Before
@@ -69,11 +69,11 @@ public void setUp() throws Exception {
             .withDocumentClass(Person.class)
             .withCodecRegistry(JacksonCodecs.registryFromMapper(mapper));
 
-    this.backend = new MongoBackend<>(this.collection);
+    this.backend = new MongoBackend(this.collection);
     this.repository = new PersonRepository(backend);
-    PersonGenerator generator = new PersonGenerator();
+    final PersonGenerator generator = new PersonGenerator();
 
-    Flowable.fromPublisher(backend.insert(generator.next().withFullName("test")))
+    Flowable.fromPublisher(collection.insertOne(generator.next().withFullName("test")))
             .test()
             .awaitDone(1, TimeUnit.SECONDS)
             .assertComplete();

value-processor/src/org/immutables/value/processor/CriteriaRepository.generator

@@ -57,9 +57,9 @@ import java.util.Objects;
 [/if]
 [type.typeDocument.access] class [type.name]Repository implements Repository.Readable<[type.name]> {
 
-  private final Backend<[type.name]> backend;
+  private final Backend backend;
 
-  public [type.name]Repository(Backend<[type.name]> backend) {
+  public [type.name]Repository(Backend backend) {
      this.backend = Objects.requireNonNull(backend, "backend");
   }