DATACOUCH-187 - Allow counting queries and single projections.

This change allows simple projections to types long, boolean, String when an inline N1QL query uses an aggregation function like AVG, COUNT.

The projection's result must be a single row with a single key/value pair in the N1QL response. Only the value gets returned.

src/test/java/org/springframework/data/couchbase/repository/query/AbstractN1qlBasedQueryTest.java

@@ -6,6 +6,7 @@ import static org.mockito.Mockito.*;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
 
 import com.couchbase.client.java.document.json.JsonArray;
 import com.couchbase.client.java.document.json.JsonObject;
@@ -18,7 +19,9 @@ import com.couchbase.client.java.query.consistency.ScanConsistency;
 import org.junit.Test;
 import org.mockito.Mockito;
 
+import org.springframework.data.couchbase.core.mapping.event.User;
 import org.springframework.data.domain.Pageable;
+import org.springframework.data.repository.query.QueryCreationException;
 import org.springframework.data.repository.query.QueryMethod;
 
 public class AbstractN1qlBasedQueryTest {
@@ -90,6 +93,7 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock, never()).executeStream(any(N1qlQuery.class));
     verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
   }
 
   @Test
@@ -109,6 +113,7 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock, never()).executeStream(any(N1qlQuery.class));
     verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
   }
 
   @Test
@@ -128,6 +133,7 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock).executeStream(any(N1qlQuery.class));
     verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
   }
 
   @Test
@@ -146,6 +152,7 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock, never()).executeStream(any(N1qlQuery.class));
     verify(mock).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
   }
 
   @Test
@@ -165,10 +172,11 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock, never()).executeStream(any(N1qlQuery.class));
     verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
   }
 
   @Test
-  public void shouldThrowWhenUnsupportedType() throws NoSuchMethodException {
+  public void shouldThrowWhenModifyingType() {
     CouchbaseQueryMethod queryMethod = Mockito.mock(CouchbaseQueryMethod.class);
     N1qlQuery query = Mockito.mock(N1qlQuery.class);
     Pageable pageable = Mockito.mock(Pageable.class);
@@ -183,5 +191,48 @@ public class AbstractN1qlBasedQueryTest {
     verify(mock, never()).executeStream(any(N1qlQuery.class));
     verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
     verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSingleProjection(any(N1qlQuery.class));
+  }
+
+  @Test
+  public void shouldExecuteSingleProjectionWhenRandomObjectReturnType() {
+    CouchbaseQueryMethod queryMethod = Mockito.mock(CouchbaseQueryMethod.class);
+    doReturn(CountDownLatch.class).when(queryMethod).getReturnedObjectType();
+
+    N1qlQuery query = Mockito.mock(N1qlQuery.class);
+    Pageable pageable = Mockito.mock(Pageable.class);
+    AbstractN1qlBasedQuery mock = mock(AbstractN1qlBasedQuery.class);
+    when(mock.executeDependingOnType(any(N1qlQuery.class), any(N1qlQuery.class), any(QueryMethod.class), any(Pageable.class),
+        anyBoolean(), anyBoolean(), anyBoolean()))
+        .thenCallRealMethod();
+
+    mock.executeDependingOnType(query, query, queryMethod, pageable, false, false, false);
+    verify(mock, never()).executeCollection(any(N1qlQuery.class));
+    verify(mock, never()).executeEntity(any(N1qlQuery.class));
+    verify(mock, never()).executeStream(any(N1qlQuery.class));
+    verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock).executeSingleProjection(any(N1qlQuery.class));
+  }
+
+  @Test
+  public void shouldExecuteSingleProjectionWhenPrimitiveReturnType() {
+    CouchbaseQueryMethod queryMethod = Mockito.mock(CouchbaseQueryMethod.class);
+    doReturn(long.class).when(queryMethod).getReturnedObjectType();
+
+    N1qlQuery query = Mockito.mock(N1qlQuery.class);
+    Pageable pageable = Mockito.mock(Pageable.class);
+    AbstractN1qlBasedQuery mock = mock(AbstractN1qlBasedQuery.class);
+    when(mock.executeDependingOnType(any(N1qlQuery.class), any(N1qlQuery.class), any(QueryMethod.class), any(Pageable.class),
+        anyBoolean(), anyBoolean(), anyBoolean()))
+        .thenCallRealMethod();
+
+    mock.executeDependingOnType(query, query, queryMethod, pageable, false, false, false);
+    verify(mock, never()).executeCollection(any(N1qlQuery.class));
+    verify(mock, never()).executeEntity(any(N1qlQuery.class));
+    verify(mock, never()).executeStream(any(N1qlQuery.class));
+    verify(mock, never()).executePaged(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock, never()).executeSliced(any(N1qlQuery.class), any(N1qlQuery.class), any(Pageable.class));
+    verify(mock).executeSingleProjection(any(N1qlQuery.class));
   }
 }