spring-projects#282 - Support ordering

Author: rchigvintsev

Diff for: src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryCreator.java

@@ -18,11 +18,10 @@
 import org.springframework.data.domain.Sort;
 import org.springframework.data.r2dbc.convert.R2dbcConverter;
 import org.springframework.data.r2dbc.core.ReactiveDataAccessStrategy;
-import org.springframework.data.relational.core.sql.Condition;
-import org.springframework.data.relational.core.sql.Expression;
+import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
+import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
+import org.springframework.data.relational.core.sql.*;
 import org.springframework.data.relational.core.sql.SelectBuilder.SelectFromAndJoin;
-import org.springframework.data.relational.core.sql.StatementBuilder;
-import org.springframework.data.relational.core.sql.Table;
 import org.springframework.data.relational.core.sql.render.RenderContext;
 import org.springframework.data.relational.core.sql.render.SqlRenderer;
 import org.springframework.data.relational.repository.query.RelationalEntityMetadata;
@@ -33,6 +32,7 @@
 
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.stream.Collectors;
 
 /**
  * Implementation of {@link AbstractQueryCreator} that creates {@link BindableQuery} from a {@link PartTree}.
@@ -108,6 +108,10 @@ protected String complete(Condition condition, Sort sort) {
             selectBuilder.where(condition);
         }
 
+        if (sort.isSorted()) {
+            selectBuilder.orderBy(getOrderBySegments(sort, fromTable));
+        }
+
         RenderContext renderContext = dataAccessStrategy.getStatementMapper().getRenderContext();
         SqlRenderer sqlRenderer = renderContext == null ? SqlRenderer.create() : SqlRenderer.create(renderContext);
         return sqlRenderer.render(selectBuilder.build());
@@ -119,4 +123,22 @@ private Collection<? extends Expression> getSelectionExpressions(Table fromTable
         }
         return fromTable.columns(dataAccessStrategy.getAllColumns(entityMetadata.getJavaType()));
     }
+
+    private Collection<? extends OrderByField> getOrderBySegments(Sort sort, Table fromTable) {
+        RelationalPersistentEntity<?> tableEntity = entityMetadata.getTableEntity();
+        return sort.get().map(order -> {
+            RelationalPersistentProperty property = tableEntity.getRequiredPersistentProperty(order.getProperty());
+            Column column = fromTable.column(property.getColumnName());
+            // TODO: org.springframework.data.relational.core.sql.render.OrderByClauseVisitor from
+            //  spring-data-relational does not prepend column name with table name. It makes sense to render
+            //  column names uniformly.
+            OrderByField orderByField = OrderByField.from(column);
+            if (order.isAscending()) {
+                orderByField = orderByField.asc();
+            } else {
+                orderByField = orderByField.desc();
+            }
+            return orderByField;
+        }).collect(Collectors.toList());
+    }
 }

Diff for: src/test/java/org/springframework/data/r2dbc/repository/query/PartTreeR2dbcQueryIntegrationTests.java

@@ -331,6 +331,19 @@ public void wrapsLikeOperatorParameterWithPercentSymbolsForContainingQuery() thr
         verify(bindSpecMock, times(1)).bind(0, "%hn%");
     }
 
+    @Test
+    public void createsQueryToFindAllEntitiesByIntegerAttributeWithDescendingOrderingByStringAttribute()
+            throws Exception {
+        R2dbcQueryMethod queryMethod = getQueryMethod("findAllByAgeOrderByLastNameDesc", Integer.class);
+        PartTreeR2dbcQuery r2dbcQuery = new PartTreeR2dbcQuery(queryMethod, databaseClient, r2dbcConverter,
+                dataAccessStrategy);
+        RelationalParametersParameterAccessor accessor = getAccessor(queryMethod, new Object[] {"oh"});
+        BindableQuery bindableQuery = r2dbcQuery.createQuery(accessor);
+        String expectedSql = "SELECT " + ALL_FIELDS + " FROM " + TABLE
+                + " WHERE " + TABLE + ".age = ? ORDER BY last_name DESC";
+        assertThat(bindableQuery.get()).isEqualTo(expectedSql);
+    }
+
     private R2dbcQueryMethod getQueryMethod(String methodName, Class<?>... parameterTypes) throws Exception {
         Method method = UserRepository.class.getMethod(methodName, parameterTypes);
         return new R2dbcQueryMethod(method, new DefaultRepositoryMetadata(UserRepository.class),
@@ -377,6 +390,8 @@ private interface UserRepository extends Repository<User, Long> {
         Flux<User> findAllByFirstNameEndingWith(String ending);
 
         Flux<User> findAllByFirstNameContaining(String containing);
+
+        Flux<User> findAllByAgeOrderByLastNameDesc(Integer age);
     }
 
     @Table("users")