Sort Support for feign pagination

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/PageJacksonModule.java

@@ -64,10 +64,17 @@ public class PageJacksonModule extends Module {
 		private final Page<T> delegate;
 
 		SimplePageImpl(@JsonProperty("content") List<T> content,
-				@JsonProperty("number") int number, @JsonProperty("size") int size,
-				@JsonProperty("totalElements") long totalElements) {
-			delegate = new PageImpl<>(content, PageRequest.of(number, size),
-					totalElements);
+			@JsonProperty("number") int number, @JsonProperty("size") int size,
+			@JsonProperty("totalElements") long totalElements, @JsonProperty("sort") Sort sort) {
+			PageRequest pageRequest;
+			if (sort != null) {
+				pageRequest = PageRequest.of(number, size, sort);
+			}
+			else {
+				pageRequest = PageRequest.of(number, size);
+			}
+			delegate = new PageImpl<>(content, pageRequest, totalElements);
+
 		}
 
 		@JsonProperty

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SortJsonComponent.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2013-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.openfeign.support;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.TreeNode;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+
+import org.springframework.data.domain.Sort;
+
+/**
+ * This class provides support to serialize and deserialize spring {@link Sort} object.
+ * @author canbezmen
+ */
+public class SortJsonComponent {
+
+	public static class SortSerializer extends JsonSerializer<Sort> {
+
+		@Override
+		public void serialize(Sort value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+			gen.writeStartArray();
+			value.iterator().forEachRemaining(v -> {
+				try {
+					gen.writeObject(v);
+				}
+				catch (IOException e) {
+					e.printStackTrace();
+				}
+			});
+			gen.writeEndArray();
+		}
+
+		@Override
+		public Class<Sort> handledType() {
+			return Sort.class;
+		}
+
+	}
+
+	public static class SortDeserializer extends JsonDeserializer<Sort> {
+
+		@Override
+		public Sort deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
+			TreeNode treeNode = jsonParser.getCodec().readTree(jsonParser);
+			if (treeNode.isArray()) {
+				ArrayNode arrayNode = (ArrayNode) treeNode;
+				List<Sort.Order> orders = new ArrayList<>();
+				for (JsonNode jsonNode : arrayNode) {
+					Sort.Order order = new Sort.Order(Sort.Direction
+						.valueOf(jsonNode.get("direction").textValue()), jsonNode.get("property").textValue());
+					orders.add(order);
+				}
+				return Sort.by(orders);
+			}
+			return null;
+		}
+
+		@Override
+		public Class<Sort> handledType() {
+			return Sort.class;
+		}
+
+	}
+}

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/support/PageJacksonModuleTests.java

@@ -16,12 +16,16 @@
 
 package org.springframework.cloud.openfeign.support;
 
+import java.util.Optional;
+
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.module.SimpleModule;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Sort;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -35,13 +39,16 @@ public class PageJacksonModuleTests {
 	@BeforeAll
 	public static void initialize() {
 		objectMapper = new ObjectMapper();
-		objectMapper.registerModule(new PageJacksonModule());
+		SimpleModule module = new SimpleModule();
+		module.addSerializer(Sort.class, new SortJsonComponent.SortSerializer());
+		module.addDeserializer(Sort.class, new SortJsonComponent.SortDeserializer());
+		objectMapper.registerModules(new PageJacksonModule(), module);
 	}
 
 	@Test
 	public void deserializePage() throws JsonProcessingException {
 		// Given
-		String pageJson = "{\"content\":[\"A name\"], \"number\":1, \"size\":2, \"totalElements\": 3}";
+		String pageJson = "{\"content\":[\"A name\"],\"number\":1,\"size\":2,\"totalElements\":3,\"sort\":[{\"direction\":\"ASC\",\"property\":\"field\",\"ignoreCase\":false,\"nullHandling\":\"NATIVE\",\"descending\":false,\"ascending\":true}]}";
 		// When
 		Page<?> result = objectMapper.readValue(pageJson, Page.class);
 		// Then
@@ -51,6 +58,13 @@ public class PageJacksonModuleTests {
 		assertThat(result.getPageable()).isNotNull();
 		assertThat(result.getPageable().getPageSize()).isEqualTo(2);
 		assertThat(result.getPageable().getPageNumber()).isEqualTo(1);
+		assertThat(result.getPageable().getSort()).hasSize(1);
+		Optional<Sort.Order> optionalOrder = result.getPageable().getSort().get().findFirst();
+		if (optionalOrder.isPresent()) {
+			Sort.Order order = optionalOrder.get();
+			assertThat(order.getDirection()).isEqualTo(Sort.Direction.ASC);
+			assertThat(order.getProperty()).isEqualTo("field");
+		}
 	}
 
 }