Make computed fields incompatible with C* 1.2 since they rely on aliases (JAVA-661)

olim7t · olim7t · commit 15bc49c4ad1d · 2015-06-30T17:11:27.000+02:00
diff --git a/driver-mapping/src/main/java/com/datastax/driver/mapping/AnnotationParser.java b/driver-mapping/src/main/java/com/datastax/driver/mapping/AnnotationParser.java
@@ -27,6 +27,7 @@
 import com.google.common.base.Strings;
 
 import com.datastax.driver.core.ConsistencyLevel;
+import com.datastax.driver.core.ProtocolVersion;
 import com.datastax.driver.mapping.MethodMapper.EnumParamMapper;
 import com.datastax.driver.mapping.MethodMapper.NestedUDTParamMapper;
 import com.datastax.driver.mapping.MethodMapper.ParamMapper;
@@ -74,7 +75,10 @@ public static <T> EntityMapper<T> parseEntity(Class<T> entityClass, EntityMapper
         for (Field field : entityClass.getDeclaredFields()) {
             if(field.isSynthetic() || (field.getModifiers() & Modifier.STATIC) == Modifier.STATIC)
                 continue;
-            
+
+            if (!mappingManager.supportsAliases && field.getAnnotation(Computed.class) != null)
+                throw new UnsupportedOperationException("Computed fields are not supported with native protocol v1");
+
             AnnotationChecks.validateAnnotations(field, "entity",
                                                  Column.class, ClusteringColumn.class, Enumerated.class, Frozen.class, FrozenKey.class,
                                                  FrozenValue.class, PartitionKey.class, Transient.class, Computed.class);
@@ -95,7 +99,7 @@ public static <T> EntityMapper<T> parseEntity(Class<T> entityClass, EntityMapper
             }
         }
 
-        AtomicInteger columnCounter = new AtomicInteger(0);
+        AtomicInteger columnCounter = mappingManager.supportsAliases ? new AtomicInteger(0) : null;
 
         Collections.sort(pks, fieldComparator);
         Collections.sort(ccs, fieldComparator);
diff --git a/driver-mapping/src/main/java/com/datastax/driver/mapping/Mapper.java b/driver-mapping/src/main/java/com/datastax/driver/mapping/Mapper.java
@@ -27,8 +27,8 @@
 import org.slf4j.LoggerFactory;
 
 import com.datastax.driver.core.*;
-import com.datastax.driver.mapping.annotations.Computed;
 import com.datastax.driver.mapping.annotations.Accessor;
+import com.datastax.driver.mapping.annotations.Computed;
 
 /**
  * An object handling the mapping of a particular class.
@@ -327,7 +327,9 @@ public Result<T> map(ResultSet resultSet) {
      * @see #map(ResultSet)
      */
     public Result<T> mapAliased(ResultSet resultSet) {
-        return new Result<T>(resultSet, mapper, protocolVersion, true);
+        return (manager.supportsAliases)
+            ? new Result<T>(resultSet, mapper, protocolVersion, true)
+            : map(resultSet);
     }
 
     /**
diff --git a/driver-mapping/src/main/java/com/datastax/driver/mapping/MappingManager.java b/driver-mapping/src/main/java/com/datastax/driver/mapping/MappingManager.java
@@ -32,6 +32,7 @@
 public class MappingManager {
 
     private final Session session;
+    final boolean supportsAliases;
 
     private volatile Map<Class<?>, Mapper<?>> mappers = Collections.<Class<?>, Mapper<?>>emptyMap();
     private volatile Map<Class<?>, UDTMapper<?>> udtMappers = Collections.<Class<?>, UDTMapper<?>>emptyMap();
@@ -44,6 +45,12 @@ public class MappingManager {
      */
     public MappingManager(Session session) {
         this.session = session;
+
+        ProtocolVersion protocolVersion = session.getCluster().getConfiguration().getProtocolOptions().getProtocolVersionEnum();
+        // The real condition should be Cassandra version >= 2.0, but mappers need this so that generated queries are compatible,
+        // and we don't know in advance the version of all future peers.
+        // At least if protocol >=2 we know there won't be any 1.2 nodes.
+        this.supportsAliases = (protocolVersion != ProtocolVersion.V1);
     }
 
     /**
diff --git a/driver-mapping/src/test/java/com/datastax/driver/mapping/MapperComputedFieldsTest.java b/driver-mapping/src/test/java/com/datastax/driver/mapping/MapperComputedFieldsTest.java
@@ -25,6 +25,7 @@
 
 import com.datastax.driver.core.*;
 import com.datastax.driver.core.exceptions.InvalidQueryException;
+import com.datastax.driver.core.utils.CassandraVersion;
 import com.datastax.driver.mapping.annotations.*;
 
 import static com.datastax.driver.core.Assertions.assertThat;
@@ -34,6 +35,7 @@
  * annotation to map computed fields.
  */
 @SuppressWarnings("unused")
+@CassandraVersion(major = 2.0)
 public class MapperComputedFieldsTest extends CCMBridge.PerClassSingleNodeCluster {
 
     @Override
