Merge pull request #19 from jhorstmann/refactor-null-handling-get-rid-of-warning-in-log

Refactored NULL handling to get rid of logged warning message

Author: Jan-M

pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>de.zalando</groupId>
     <artifactId>zalando-sprocwrapper</artifactId>
-    <version>1.3.0</version>
+    <version>1.3.1-SNAPSHOT</version>
     <packaging>jar</packaging>
     <name>Stored Procedure Wrapper</name>
     <description>Library to make PostgreSQL stored procedures available through simple Java "*SProcService" interfaces including automatic object serialization and deserialization (using typemapper and convention-over-configuration). Supports sharding, advisory locking, statement timeouts and PostgreSQL types such as enums and hstore.</description>

src/main/java/de/zalando/typemapper/core/Mapping.java

@@ -194,9 +194,6 @@ public FieldMapper getFieldMapper() throws NotsupportedTypeException, Instantiat
             }
 
             fieldMapper = FieldMapperRegister.getMapperForClass(getFieldClass());
-            if (fieldMapper == null) {
-                throw new NotsupportedTypeException("Could not find mapper for type " + getFieldClass());
-            }
         }
 
         return fieldMapper;

src/main/java/de/zalando/typemapper/core/TypeMapper.java

@@ -154,17 +154,11 @@ private void fillObject(final Object result, final ResultTree tree) throws SQLEx
                 // TODO pribeiro we need to distinguish between null value and a mapping not defined in the tree
                 if (node == null) {
 
-                    // this may be okay - if any return value is NULL, we will reach this path.
-                    // to classify and mark this as an error, we need more information.
-                    LOG.trace("Could not map property {} of class {}: field not in result tree, field may be nullable.",
-                        mapping.getName(), resultClass.getSimpleName());
-                    continue;
-                }
-
-                if (DbResultNodeType.MAP != node.getNodeType() && node.getValue() == null) {
                     if (mapping.isOptionalField()) {
                         mapping.map(result, null);
                     }
+
+                    continue;
                 }
 
                 // TODO pribeiro we should use polymorphism instead. Build like a chain.

src/main/java/de/zalando/typemapper/core/fieldMapper/FieldMapperRegister.java

@@ -3,9 +3,7 @@
 import java.math.BigDecimal;
 
 import java.util.Date;
-import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 import de.zalando.typemapper.core.ValueTransformer;
@@ -15,6 +13,8 @@ public class FieldMapperRegister {
     @SuppressWarnings({ "rawtypes" })
     private static final Map<Class, FieldMapper> register = new ConcurrentHashMap<Class, FieldMapper>();
 
+    private static final NullFieldMapper NULL_FIELD_MAPPER = new NullFieldMapper();
+
     static {
         final FieldMapper dateFieldMapper = new DateFieldMapper();
         FieldMapperRegister.register(Date.class, dateFieldMapper);
@@ -62,12 +62,6 @@ public class FieldMapperRegister {
 
         final FieldMapper hstoreMapper = new HStoreFieldMapper();
         FieldMapperRegister.register(Map.class, hstoreMapper);
-
-        final FieldMapper nullListMapper = new NullListFieldMapper();
-        FieldMapperRegister.register(List.class, nullListMapper);
-
-        final FieldMapper nullSetMapper = new NullSetFieldMapper();
-        FieldMapperRegister.register(Set.class, nullSetMapper);
     }
 
     @SuppressWarnings("rawtypes")
@@ -96,6 +90,10 @@ public static FieldMapper getMapperForClass(final Class clazz) {
             }
         }
 
+        if (fieldMapper == null) {
+            fieldMapper = NULL_FIELD_MAPPER;
+        }
+
         return fieldMapper;
     }
 

src/main/java/de/zalando/typemapper/core/fieldMapper/NullFieldMapper.java

@@ -0,0 +1,18 @@
+package de.zalando.typemapper.core.fieldMapper;
+
+/**
+ * sentinel mapper for NULL fields returned from database. Has to be registered as last mapper in
+ * {@link de.zalando.typemapper.core.fieldMapper.FieldMapperRegister}.
+ */
+public class NullFieldMapper implements FieldMapper {
+
+    @Override
+    public Object mapField(final String string, final Class clazz) {
+        if (string != null) {
+            throw new IllegalStateException("Could not find mapper for type " + clazz);
+        } else {
+            return null;
+        }
+    }
+
+}