DATAREDIS-1001 - Fix java.util.Date hash mapping when flattening out entries.

The AsArrayTypeDeserializer causes date values to be rendered as an array like [java.util.Date, 1561543964015] an therefore is 1. skipped when flattening and 2. if not skipped cannot be read back. We now register an error handler along with a custom deserializer aware of the used date format to write and read date values without having to store an array but just the date msec. Original pull request: spring-projects#467.

Author: christophstrobl

src/main/java/org/springframework/data/redis/hash/Jackson2HashMapper.java

@@ -16,7 +16,9 @@
 package org.springframework.data.redis.hash;
 
 import java.io.IOException;
+import java.text.ParseException;
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
@@ -29,15 +31,28 @@
 import org.springframework.data.mapping.MappingException;
 import org.springframework.data.util.DirectFieldAccessFallbackBeanWrapper;
 import org.springframework.util.Assert;
+import org.springframework.util.NumberUtils;
 import org.springframework.util.StringUtils;
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.BeanDescription;
+import com.fasterxml.jackson.databind.DeserializationConfig;
+import com.fasterxml.jackson.databind.DeserializationContext;
 import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.JsonDeserializer;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.databind.deser.BeanDeserializerModifier;
+import com.fasterxml.jackson.databind.deser.DeserializationProblemHandler;
+import com.fasterxml.jackson.databind.deser.std.UntypedObjectDeserializer;
+import com.fasterxml.jackson.databind.jsontype.TypeIdResolver;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.databind.type.TypeFactory;
 
 /**
  * {@link ObjectMapper} based {@link HashMapper} implementation that allows flattening. Given an entity {@code Person}
@@ -65,19 +80,56 @@
  *
  * <strong>Normal</strong>
  * <table>
- * <tr><th>Hash field</th><th>Value<th></tr>
- * <tr><td>firstname</td><td>Jon<td></tr>
- * <tr><td>lastname</td><td>Snow<td></tr>
- * <tr><td>address</td><td>{ "city" : "Castle Black", "country" : "The North" }<td></tr>
+ * <tr>
+ * <th>Hash field</th>
+ * <th>Value
+ * <th>
+ * </tr>
+ * <tr>
+ * <td>firstname</td>
+ * <td>Jon
+ * <td>
+ * </tr>
+ * <tr>
+ * <td>lastname</td>
+ * <td>Snow
+ * <td>
+ * </tr>
+ * <tr>
+ * <td>address</td>
+ * <td>{ "city" : "Castle Black", "country" : "The North" }
+ * <td>
+ * </tr>
  * </table>
  * <br />
  * <strong>Flat</strong>:
  * <table>
- * <tr><th>Hash field</th><th>Value<th></tr>
- *   <tr><td>firstname</td><td>Jon<td></tr>
- * <tr><td>lastname</td><td>Snow<td></tr>
- * <tr><td>address.city</td><td>Castle Black<td></tr>
- * <tr><td>address.country</td><td>The North<td></tr>
+ * <tr>
+ * <th>Hash field</th>
+ * <th>Value
+ * <th>
+ * </tr>
+ *  
+ * <tr>
+ * <td>firstname</td>
+ * <td>Jon
+ * <td>
+ * </tr>
+ * <tr>
+ * <td>lastname</td>
+ * <td>Snow
+ * <td>
+ * </tr>
+ * <tr>
+ * <td>address.city</td>
+ * <td>Castle Black
+ * <td>
+ * </tr>
+ * <tr>
+ * <td>address.country</td>
+ * <td>The North
+ * <td>
+ * </tr>
  * </table>
  *
  * @author Christoph Strobl
@@ -103,6 +155,50 @@ public Jackson2HashMapper(boolean flatten) {
 typingMapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
 typingMapper.setSerializationInclusion(Include.NON_NULL);
 typingMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+
+typingMapper.addHandler(new DeserializationProblemHandler() {
+@Override
+public JavaType handleMissingTypeId(DeserializationContext ctxt, JavaType baseType, TypeIdResolver idResolver,
+String failureMsg) {
+return TypeFactory.defaultInstance().constructSimpleType(java.util.Date.class, new JavaType[] {});
+}
+});
+
+SimpleModule module = new SimpleModule();
+module.setDeserializerModifier(new BeanDeserializerModifier() {
+@Override
+public JsonDeserializer<?> modifyDeserializer(DeserializationConfig config, BeanDescription beanDesc,
+JsonDeserializer<?> deserializer) {
+
+if (beanDesc.getBeanClass().equals(java.util.Date.class)) {
+return new JsonDeserializer<Object>() {
+
+JsonDeserializer<?> delegate = new UntypedObjectDeserializer(null, null);
+
+@Override
+public Object deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
+
+Object val = delegate.deserialize(p, ctxt);
+
+if (val instanceof Date) {
+return val;
+}
+
+try {
+return ctxt.getConfig().getDateFormat().parse(val.toString());
+} catch (ParseException e) {
+e.printStackTrace();
+return new Date(NumberUtils.parseNumber(val.toString(), Long.class));
+}
+}
+};
+}
+
+return deserializer;
+}
+});
+
+typingMapper.registerModule(module);
 }
 
 /**
@@ -242,6 +338,7 @@ private void flattenElement(String propertyPrefix, Object source, Map<String, Ob
 }
 
 JsonNode element = (JsonNode) source;
+
 if (element.isArray()) {
 
 Iterator<JsonNode> nodes = element.elements();
@@ -250,7 +347,13 @@ private void flattenElement(String propertyPrefix, Object source, Map<String, Ob
 
 JsonNode cur = nodes.next();
 if (cur.isArray()) {
-this.falttenCollection(propertyPrefix, cur.elements(), resultMap);
+this.flattenCollection(propertyPrefix, cur.elements(), resultMap);
+} else {
+
+if (cur.asText().equals("java.util.Date")) {
+resultMap.put(propertyPrefix, nodes.next().asText());
+break;
+}
 }
 }
 
@@ -261,7 +364,7 @@ private void flattenElement(String propertyPrefix, Object source, Map<String, Ob
 }
 }
 
-private void falttenCollection(String propertyPrefix, Iterator<JsonNode> list, Map<String, Object> resultMap) {
+private void flattenCollection(String propertyPrefix, Iterator<JsonNode> list, Map<String, Object> resultMap) {
 
 int counter = 0;
 while (list.hasNext()) {

src/test/java/org/springframework/data/redis/mapping/Jackson2HashMapperTests.java

@@ -97,5 +97,4 @@ public void shouldWriteReadHashCorrectly() {
 Person result = (Person) mapper.fromHash(template.<String, Object> opsForHash().entries("JON-SNOW"));
 Assert.assertThat(result, Is.is(jon));
 }
-
 }

src/test/java/org/springframework/data/redis/mapping/Jackson2HashMapperUnitTests.java

@@ -20,6 +20,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Date;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -161,6 +162,16 @@ public void nestedStuff() {
 assertBackAndForwardMapping(outer);
 }
 
+@Test // DATAREDIS-1001
+public void dateValueShouldBeTreatedCorrectly() {
+
+WithDate source = new WithDate();
+source.string = "id-1";
+source.date = new Date(1561543964015L);
+
+assertBackAndForwardMapping(source);
+}
+
 @Data
 public static class WithList {
 List<String> strings;
@@ -174,4 +185,11 @@ public static class WithMap {
 Map<String, Object> objects;
 Map<String, Person> persons;
 }
+
+@Data
+static class WithDate {
+
+private String string;
+private Date date;
+}
 }