Judge Property.empty

Author: zhangrongfan

mybatis-boost-core/src/main/java/cn/mybatisboost/json/JsonResultSetsHandler.java

@@ -34,10 +34,7 @@ public Object intercept(Invocation invocation) throws Throwable {
 
         for (Object object : proceed) {
             for (Field field : fields) {
-                Object value = field.get(object);
-                if (value != null) {
-                    value = ((Property<?>) value).get();
-                }
+                Object value = ((Property<?>) field.get(object)).orElse(null);
                 if (value instanceof String) {
                     field.set(object, Property.of(JsonTypeHandler.objectMapper.readValue((String) value,
                             (Class<?>) ((ParameterizedType) field.getGenericType()).getActualTypeArguments()[0])));

mybatis-boost-core/src/main/java/cn/mybatisboost/json/JsonTypeHandler.java

@@ -21,24 +21,28 @@ public class JsonTypeHandler extends BaseTypeHandler<Property<?>> {
     public void setNonNullParameter(PreparedStatement ps, int i, Property<?> parameter, JdbcType jdbcType)
             throws SQLException {
         try {
-            ps.setString(i, objectMapper.writeValueAsString(parameter.get()));
+            if (parameter.isPresent()) {
+                ps.setString(i, objectMapper.writeValueAsString(parameter.get()));
+            } else {
+                ps.setNull(i, ps.getParameterMetaData().getParameterType(i));
+            }
         } catch (JsonProcessingException e) {
             throw new RuntimeException(e);
         }
     }
 
     @Override
     public Property<?> getNullableResult(ResultSet rs, String columnName) throws SQLException {
-        return Property.of(rs.getString(columnName));
+        return Property.ofNullable(rs.getString(columnName));
     }
 
     @Override
     public Property<?> getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
-        return Property.of(rs.getString(columnIndex));
+        return Property.ofNullable(rs.getString(columnIndex));
     }
 
     @Override
     public Property<?> getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
-        return Property.of(cs.getString(columnIndex));
+        return Property.ofNullable(cs.getString(columnIndex));
     }
 }

mybatis-boost-core/src/main/java/cn/mybatisboost/support/Property.java

@@ -1,26 +1,40 @@
 package cn.mybatisboost.support;
 
+import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 public class Property<T> {
 
+    private static final Property<?> EMPTY = new Property<>();
     private final T value;
 
     private Property() {
         this.value = null;
     }
 
     private Property(T value) {
-        this.value = value;
+        this.value = Objects.requireNonNull(value);
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <T> Property<T> empty() {
+        return (Property<T>) EMPTY;
     }
 
     public static <T> Property<T> of(T value) {
         return new Property<>(value);
     }
 
+    public static <T> Property<T> ofNullable(T value) {
+        return value == null ? empty() : of(value);
+    }
+
     public T get() {
+        if (value == null) {
+            throw new NoSuchElementException("No value present");
+        }
         return value;
     }
 

mybatis-boost-core/src/main/java/cn/mybatisboost/util/EntityUtils.java

@@ -1,6 +1,7 @@
 package cn.mybatisboost.util;
 
 import cn.mybatisboost.core.adaptor.NameAdaptor;
+import cn.mybatisboost.support.Property;
 import cn.mybatisboost.util.function.UncheckedFunction;
 import cn.mybatisboost.util.function.UncheckedPredicate;
 import org.apache.commons.lang3.StringUtils;
@@ -67,7 +68,10 @@ public static List<String> getProperties(Object entity, boolean selective) {
             properties = properties.stream()
                     .map(UncheckedFunction.of(type::getDeclaredField))
                     .peek(f -> f.setAccessible(true))
-                    .filter(UncheckedPredicate.of(f -> f.get(entity) != null))
+                    .filter(UncheckedPredicate.of(f -> {
+                        Object value = f.get(entity);
+                        return value != null && (!(value instanceof Property) || ((Property<?>) value).isPresent());
+                    }))
                     .map(UncheckedFunction.of(Field::getName))
                     .collect(Collectors.toList());
         }
@@ -84,7 +88,10 @@ public static List<String> getProperties(List<?> entities) {
             try {
                 Field field = type.getDeclaredField(iterator.next());
                 boolean nonNull = entities.stream()
-                        .anyMatch(UncheckedPredicate.of(it -> field.get(it) != null));
+                        .anyMatch(UncheckedPredicate.of(it -> {
+                            Object value = field.get(it);
+                            return value != null && (!(value instanceof Property) || ((Property<?>) value).isPresent());
+                        }));
                 if (!nonNull) iterator.remove();
             } catch (NoSuchFieldException e) {
                 throw new RuntimeException(e);