DATACOUCH-206 - Provides a way to set distinct consistency on repository methods.

* add @WithConsistency annotation
* evaluate it and set consistency in AbstractN1qlBasedQuery
* evaluate it and set consistency in ReactiveAbstractN1qlBasedQuery
* add documentation on @WithConsistency

Original pull request: #198.

src/main/java/org/springframework/data/couchbase/core/query/WithConsistency.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2013-2019 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
+ *
+ *      https://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.query;
+
+import com.couchbase.client.java.query.consistency.ScanConsistency;
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import org.springframework.data.annotation.QueryAnnotation;
+import org.springframework.data.couchbase.config.AbstractCouchbaseConfiguration;
+
+/**
+ * Annotation to set the scan consistency of N1QL queries with Couchbase.
+ * This controls whether couchbase waits for all changes to be processed by an index
+ * or whether stale results are acceptable.
+ * <p/>
+ * If not set, the default consistency set in {@link AbstractCouchbaseConfiguration#getDefaultConsistency()} is used.
+ *
+ * @author Johannes Jasper.
+ */
+@Documented
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+@QueryAnnotation
+public @interface WithConsistency {
+
+  ScanConsistency value();
+
+}

src/main/java/org/springframework/data/couchbase/repository/query/AbstractN1qlBasedQuery.java

@@ -16,11 +16,6 @@
 
 package org.springframework.data.couchbase.repository.query;
 
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-
 import com.couchbase.client.java.document.json.JsonArray;
 import com.couchbase.client.java.document.json.JsonObject;
 import com.couchbase.client.java.document.json.JsonValue;
@@ -28,9 +23,11 @@ import com.couchbase.client.java.query.N1qlParams;
 import com.couchbase.client.java.query.N1qlQuery;
 import com.couchbase.client.java.query.Statement;
 import com.couchbase.client.java.query.consistency.ScanConsistency;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.springframework.data.couchbase.core.CouchbaseOperations;
 import org.springframework.data.couchbase.core.CouchbaseQueryExecutionException;
 import org.springframework.data.domain.PageImpl;
@@ -52,6 +49,7 @@ import org.springframework.util.Assert;
  * @author Simon Baslé
  * @author Subhashni Balakrishnan
  * @author Mark Paluch
+ * @author Johannes Jasper
  */
 public abstract class AbstractN1qlBasedQuery implements RepositoryQuery {
 
@@ -82,6 +80,15 @@ public abstract class AbstractN1qlBasedQuery implements RepositoryQuery {
 
   protected abstract JsonValue getPlaceholderValues(ParameterAccessor accessor);
 
+  protected ScanConsistency getScanConsistency() {
+
+    if (queryMethod.hasConsistencyAnnotation()) {
+      return queryMethod.getConsistencyAnnotation().value();
+    }
+
+    return getCouchbaseOperations().getDefaultConsistency().n1qlConsistency();
+  }
+
   @Override
   public Object execute(Object[] parameters) {
     ParametersParameterAccessor accessor = new ParametersParameterAccessor(queryMethod.getParameters(), parameters);
@@ -96,14 +103,12 @@ public abstract class AbstractN1qlBasedQuery implements RepositoryQuery {
     JsonValue queryPlaceholderValues = getPlaceholderValues(accessor);
 
     //prepare the final query
-    N1qlQuery query = buildQuery(statement, queryPlaceholderValues,
-        getCouchbaseOperations().getDefaultConsistency().n1qlConsistency());
+    N1qlQuery query = buildQuery(statement, queryPlaceholderValues, getScanConsistency());
 
     //prepare a count query
     Statement countStatement = getCount(accessor, parameters);
     //the place holder values are the same for the count query as well
-    N1qlQuery countQuery = buildQuery(countStatement, queryPlaceholderValues,
-        getCouchbaseOperations().getDefaultConsistency().n1qlConsistency());
+    N1qlQuery countQuery = buildQuery(countStatement, queryPlaceholderValues, getScanConsistency());
     return processor.processResult(executeDependingOnType(query, countQuery, queryMethod, accessor.getPageable(), typeToRead));
   }
 

src/main/java/org/springframework/data/couchbase/repository/query/CouchbaseQueryMethod.java

@@ -24,6 +24,7 @@ import org.springframework.data.couchbase.core.mapping.CouchbasePersistentProper
 import org.springframework.data.couchbase.core.query.Dimensional;
 import org.springframework.data.couchbase.core.query.Query;
 import org.springframework.data.couchbase.core.query.View;
+import org.springframework.data.couchbase.core.query.WithConsistency;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.projection.ProjectionFactory;
 import org.springframework.data.repository.core.RepositoryMetadata;
@@ -144,6 +145,14 @@ public class CouchbaseQueryMethod extends QueryMethod {
     return getInlineN1qlQuery() != null;
   }
 
+  public boolean hasConsistencyAnnotation() {
+    return getConsistencyAnnotation() != null;
+  }
+
+  public WithConsistency getConsistencyAnnotation() {
+    return method.getAnnotation(WithConsistency.class);
+  }
+
   /**
    * Returns the query string declared in a {@link Query} annotation or {@literal null} if neither the annotation found
    * nor the attribute was specified.

src/main/java/org/springframework/data/couchbase/repository/query/ReactiveAbstractN1qlBasedQuery.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.couchbase.repository.query;
 
+import com.couchbase.client.java.query.consistency.ScanConsistency;
 import java.util.Map;
 import com.couchbase.client.java.document.json.JsonValue;
 import com.couchbase.client.java.query.N1qlQuery;
@@ -31,6 +32,7 @@ import reactor.core.publisher.Flux;
 /**
  * @author Subhashni Balakrishnan
  * @author Mark Paluch
+ * @author Johannes Jasper
  * @since 3.0
  */
 public abstract class ReactiveAbstractN1qlBasedQuery implements RepositoryQuery {
@@ -61,8 +63,7 @@ public abstract class ReactiveAbstractN1qlBasedQuery implements RepositoryQuery
         JsonValue queryPlaceholderValues = getPlaceholderValues(accessor);
 
         //prepare the final query
-        N1qlQuery query = N1qlUtils.buildQuery(statement, queryPlaceholderValues,
-                getCouchbaseOperations().getDefaultConsistency().n1qlConsistency());
+        N1qlQuery query = N1qlUtils.buildQuery(statement, queryPlaceholderValues, getScanConsistency());
         return ReactiveWrapperConverters.toWrapper(
                 processor.processResult(executeDependingOnType(query, queryMethod, typeToRead)), Flux.class);
     }
@@ -115,4 +116,13 @@ public abstract class ReactiveAbstractN1qlBasedQuery implements RepositoryQuery
     protected RxJavaCouchbaseOperations getCouchbaseOperations() {
         return this.couchbaseOperations;
     }
+
+    protected ScanConsistency getScanConsistency() {
+
+      if (queryMethod.hasConsistencyAnnotation()) {
+        return queryMethod.getConsistencyAnnotation().value();
+      }
+
+      return getCouchbaseOperations().getDefaultConsistency().n1qlConsistency();
+    }
 }