Abstraction for JSON object mapper (#3319)

* Edited gson dependency as optional and add jackson dependency only for tests purpose

* Created exception for config error purpose

* Classes and interfaces created to gain code decoupling from json convertion implementation

* Class is no longer needed

* Interfaces created as contract for all redis command json operations to set an implementation of a json convertion by polymorphism

* Changed json engine implementation to an interface to decouple code and make it interchangeable

* Implemented contract to define a json engine encoding/decoding

* classes created for json conversion with different json engines for testing purposes and junit tests for them

* Removed import that is no longer used

* Removed the optional statement for gson lib to not break the change

* Just removed unused exception

* Edited to use a plain jedis exception instead of a custom one

* setting gson as default json parser automatically when none set

* Removed unnecessary interface but kept setters for json serializer/deserializer engine configuration

* Unused imports removed

* Classes, interfaces, methods and other comment references renamed from word 'parser' to 'object mapper'.

* Classes and interfaces moved to 'json' package because it's not need a separate package

* Made some tweaks to the custom object mapper for jackson which throws a jedi's Exception instead of just printing stack trace.

* Refactored method to get json object mapper reference using double checked lock approach as suggestion in review code

* Removed unit test no longer occurs jedis exception after refactoring json object mapper instance in 'command object class'

* Unused imports removed

Author: clebersonp

pom.xml

@@ -103,6 +103,18 @@
 			<version>3.12.4</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-databind</artifactId>
+			<version>2.14.2</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.datatype</groupId>
+			<artifactId>jackson-datatype-jsr310</artifactId>
+			<version>2.14.2</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<distributionManagement>

src/main/java/redis/clients/jedis/CommandObjects.java

@@ -23,6 +23,7 @@
 import redis.clients.jedis.json.JsonSetParams;
 import redis.clients.jedis.json.Path;
 import redis.clients.jedis.json.Path2;
+import redis.clients.jedis.json.JsonObjectMapper;
 import redis.clients.jedis.params.*;
 import redis.clients.jedis.providers.ConnectionProvider;
 import redis.clients.jedis.resps.*;
@@ -4300,4 +4301,8 @@ public Response<List<String>> graphProfile(String graphName, String query) {
   public Response<Long> waitReplicas(int replicas, long timeout) {
     return appendCommand(commandObjects.waitReplicas(replicas, timeout));
   }
+
+  public void setJsonObjectMapper(JsonObjectMapper jsonObjectMapper) {
+    this.commandObjects.setJsonObjectMapper(jsonObjectMapper);
+  }
 }

src/main/java/redis/clients/jedis/GsonJson.java

@@ -20,6 +20,7 @@
 import redis.clients.jedis.json.JsonSetParams;
 import redis.clients.jedis.json.Path;
 import redis.clients.jedis.json.Path2;
+import redis.clients.jedis.json.JsonObjectMapper;
 import redis.clients.jedis.params.*;
 import redis.clients.jedis.resps.*;
 import redis.clients.jedis.search.*;
@@ -4361,4 +4362,8 @@ public Response<Object> sendCommand(CommandArguments args) {
   public <T> Response<T> executeCommand(CommandObject<T> command) {
     return appendCommand(command);
   }
+
+  public void setJsonObjectMapper(JsonObjectMapper jsonObjectMapper) {
+    this.commandObjects.setJsonObjectMapper(jsonObjectMapper);
+  }
 }

src/main/java/redis/clients/jedis/MultiNodePipelineBase.java

@@ -26,6 +26,7 @@
 import redis.clients.jedis.json.JsonSetParams;
 import redis.clients.jedis.json.Path;
 import redis.clients.jedis.json.Path2;
+import redis.clients.jedis.json.JsonObjectMapper;
 import redis.clients.jedis.params.*;
 import redis.clients.jedis.resps.*;
 import redis.clients.jedis.search.*;
@@ -4376,4 +4377,8 @@ public Response<Object> sendCommand(CommandArguments args) {
   public <T> Response<T> executeCommand(CommandObject<T> command) {
     return appendCommand(command);
   }
+
+  public void setJsonObjectMapper(JsonObjectMapper jsonObjectMapper) {
+    this.commandObjects.setJsonObjectMapper(jsonObjectMapper);
+  }
 }

src/main/java/redis/clients/jedis/Pipeline.java

@@ -23,6 +23,7 @@
 import redis.clients.jedis.json.JsonSetParams;
 import redis.clients.jedis.json.Path;
 import redis.clients.jedis.json.Path2;
+import redis.clients.jedis.json.JsonObjectMapper;
 import redis.clients.jedis.params.*;
 import redis.clients.jedis.providers.*;
 import redis.clients.jedis.resps.*;
@@ -4643,4 +4644,8 @@ public Object sendBlockingCommand(String sampleKey, ProtocolCommand cmd, String.
   public Object executeCommand(CommandArguments args) {
     return executeCommand(new CommandObject<>(args, BuilderFactory.RAW_OBJECT));
   }
+
+  public void setJsonObjectMapper(JsonObjectMapper jsonObjectMapper) {
+    this.commandObjects.setJsonObjectMapper(jsonObjectMapper);
+  }
 }

src/main/java/redis/clients/jedis/TransactionBase.java

@@ -0,0 +1,26 @@
+package redis.clients.jedis.json;
+
+import com.google.gson.Gson;
+
+/**
+ * Use the default {@link Gson} configuration for serialization and deserialization JSON
+ * operations.
+ * <p>When none is explicitly set, this will be set.</p>
+ * @see JsonObjectMapper Create a custom JSON serializer/deserializer
+ */
+public class DefaultGsonObjectMapper implements JsonObjectMapper {
+  /**
+   * Instance of Gson object with default gson configuration.
+   */
+  private final Gson gson = new Gson();
+
+  @Override
+  public <T> T fromJson(String value, Class<T> valueType) {
+    return gson.fromJson(value, valueType);
+  }
+
+  @Override
+  public String toJson(Object value) {
+    return gson.toJson(value);
+  }
+}

src/main/java/redis/clients/jedis/UnifiedJedis.java

@@ -0,0 +1,25 @@
+package redis.clients.jedis.json;
+
+/**
+ * Represents the ability of serialize an object to JSON format string and deserialize it to the
+ * typed object.
+ * @see DefaultGsonObjectMapper Default implementation for <em>JSON serializer/deserializer</em>
+ *     engine with com.google.gson.Gson
+ */
+public interface JsonObjectMapper {
+  /**
+   * Perform deserialization from JSON format string to the given type object as argument.
+   * @param value     the JSON format
+   * @param valueType the object type to convert
+   * @param <T>       the type object to convert
+   * @return the instance of an object to the type given argument
+   */
+  <T> T fromJson(String value, Class<T> valueType);
+
+  /**
+   * Perform serialization from object to JSON format string.
+   * @param value the object to convert
+   * @return the JSON format string
+   */
+  String toJson(Object value);
+}

src/main/java/redis/clients/jedis/json/DefaultGsonObjectMapper.java

@@ -1,5 +1,6 @@
 package redis.clients.jedis.modules.json;
 
+import java.time.Instant;
 import java.util.Objects;
 
 public class JsonObjects {
@@ -99,4 +100,19 @@ public boolean equals(Object o) {
           && Objects.equals(baz, other.baz);
     }
   }
+
+  public static class Person {
+    private final String id;
+    private final Instant created;
+    public Person(String id, Instant created) {
+      this.id = id;
+      this.created = created;
+    }
+    public String getId() {
+      return id;
+    }
+    public Instant getCreated() {
+      return created;
+    }
+  }
 }

src/main/java/redis/clients/jedis/json/JsonObjectMapper.java

@@ -7,6 +7,8 @@
 import com.google.gson.Gson;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonObject;
+
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -17,6 +19,7 @@
 import redis.clients.jedis.json.JsonSetParams;
 import redis.clients.jedis.json.Path;
 import redis.clients.jedis.modules.RedisModuleCommandsTestBase;
+import redis.clients.jedis.util.JsonObjectMapperTestUtil;
 
 public class RedisJsonV1Test extends RedisModuleCommandsTestBase {
 
@@ -490,4 +493,42 @@ public void resp() {
     assertEquals("2.5", arr.get(3));
     assertEquals("true", arr.get(4));
   }
+
+  @Test
+  public void testJsonGsonParser() {
+    Person person = new Person("foo", Instant.now());
+
+    // setting the custom json gson parser
+    client.setJsonObjectMapper(JsonObjectMapperTestUtil.getCustomGsonObjectMapper());
+
+    client.jsonSet(person.getId(), ROOT_PATH, person);
+
+    String valueExpected = client.jsonGet(person.getId(), String.class, Path.of(".created"));
+    assertEquals(valueExpected, person.getCreated().toString());
+  }
+
+  @Test
+  public void testDefaultJsonGsonParserStringsMustBeDifferent() {
+    Person person = new Person("foo", Instant.now());
+
+    // using the default json gson parser which is automatically configured
+
+    client.jsonSet(person.getId(), ROOT_PATH, person);
+
+    Object valueExpected = client.jsonGet(person.getId(), Path.of(".created"));
+    assertNotEquals(valueExpected, person.getCreated().toString());
+  }
+
+  @Test
+  public void testJsonJacksonParser() {
+    Person person = new Person("foo", Instant.now());
+
+    // setting the custom json jackson parser
+    client.setJsonObjectMapper(JsonObjectMapperTestUtil.getCustomJacksonObjectMapper());
+
+    client.jsonSet(person.getId(), ROOT_PATH, person);
+
+    String valueExpected = client.jsonGet(person.getId(), String.class, Path.of(".created"));
+    assertEquals(valueExpected, person.getCreated().toString());
+  }
 }

src/test/java/redis/clients/jedis/modules/json/JsonObjects.java

@@ -0,0 +1,92 @@
+package redis.clients.jedis.util;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import com.google.gson.*;
+import redis.clients.jedis.exceptions.JedisException;
+import redis.clients.jedis.json.JsonObjectMapper;
+
+import java.lang.reflect.Type;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
+import java.time.temporal.TemporalAccessor;
+
+public class JsonObjectMapperTestUtil {
+  public static CustomJacksonObjectMapper getCustomJacksonObjectMapper() {
+    ObjectMapper om = new ObjectMapper();
+    om.registerModule(new JavaTimeModule());
+    om.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
+    return new CustomJacksonObjectMapper(om);
+  }
+
+  public static CustomGsonObjectMapper getCustomGsonObjectMapper() {
+    final class InstantAdapter implements JsonSerializer<Instant>, JsonDeserializer<Instant> {
+      DateTimeFormatter format = DateTimeFormatter.ISO_INSTANT;
+
+      @Override
+      public Instant deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+          throws JsonParseException {
+        JsonPrimitive primitive = json.getAsJsonPrimitive();
+        if (!primitive.isJsonNull()) {
+          String asString = primitive.getAsString();
+          TemporalAccessor temporalAccessor = format.parse(asString);
+          return Instant.from(temporalAccessor);
+        }
+        return null;
+      }
+
+      @Override
+      public JsonElement serialize(Instant src, Type typeOfSrc, JsonSerializationContext context) {
+        return new JsonPrimitive(format.format(src));
+      }
+    }
+    return new CustomGsonObjectMapper(
+        new GsonBuilder().registerTypeAdapter(Instant.class, new InstantAdapter()).create());
+  }
+
+  public static class CustomJacksonObjectMapper implements JsonObjectMapper {
+    private final ObjectMapper om;
+
+    CustomJacksonObjectMapper(ObjectMapper om) {
+      this.om = om;
+    }
+
+    @Override
+    public <T> T fromJson(String value, Class<T> valueType) {
+      try {
+        return om.readValue(value, valueType);
+      } catch (JsonProcessingException e) {
+        throw new JedisException(e);
+      }
+    }
+
+    @Override
+    public String toJson(Object value) {
+      try {
+        return om.writeValueAsString(value);
+      } catch (JsonProcessingException e) {
+        throw new JedisException(e);
+      }
+    }
+  }
+
+  public static class CustomGsonObjectMapper implements JsonObjectMapper {
+    private final Gson gson;
+
+    public CustomGsonObjectMapper(Gson gson) {
+      this.gson = gson;
+    }
+
+    @Override
+    public <T> T fromJson(String value, Class<T> valueType) {
+      return gson.fromJson(value, valueType);
+    }
+
+    @Override
+    public String toJson(Object value) {
+      return gson.toJson(value);
+    }
+  }
+}