Refactor UnmodifiableListDeserializer and UnmodifiableSetDeserializer to Use Abstract Base Class

Author: hyunmin0317

core/src/main/java/org/springframework/security/jackson2/AbstractUnmodifiableCollectionDeserializer.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2024 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.security.jackson2;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Abstract base class for deserializers that create unmodifiable collections from JSON data.
+ * Subclasses like {@link UnmodifiableListDeserializer} and
+ * {@link UnmodifiableSetDeserializer} should implement the method to define the
+ * specific collection type and handle the deserialization logic.
+ *
+ * @param <T> the type of the unmodifiable collection, such as {@link List} or {@link Set}.
+ * @author Hyunmin Choi
+ */
+abstract class AbstractUnmodifiableCollectionDeserializer<T> extends JsonDeserializer<T> {
+
+	@Override
+	public T deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
+		ObjectMapper mapper = (ObjectMapper) jp.getCodec();
+		JsonNode node = mapper.readTree(jp);
+		return createUnmodifiableCollection(node, mapper);
+	}
+
+	/**
+	 * Creates an unmodifiable collection from the given JSON node.
+	 *
+	 * @param node the JSON node containing the data to be deserialized.
+	 * @param mapper the {@link ObjectMapper} used to deserialize JSON data.
+	 * @return an unmodifiable collection with the deserialized elements.
+	 * @throws IOException if an error occurs during deserialization.
+	 */
+	protected abstract T createUnmodifiableCollection(JsonNode node, ObjectMapper mapper) throws IOException;
+
+	/**
+	 * Adds elements from the JSON node to the provided collection.
+	 *
+	 * @param node the JSON node containing the elements to add.
+	 * @param mapper the {@link ObjectMapper} used for deserialization.
+	 * @param collection the collection to which elements are added.
+	 * @throws IOException if an error occurs during deserialization.
+	 */
+	protected void addElements(JsonNode node, ObjectMapper mapper, Collection<Object> collection) throws IOException {
+		if (node instanceof ArrayNode arrayNode) {
+			for (JsonNode elementNode : arrayNode) {
+				collection.add(mapper.readValue(elementNode.traverse(mapper), Object.class));
+			}
+		} else if (node != null) {
+			collection.add(mapper.readValue(node.traverse(mapper), Object.class));
+		}
+	}
+
+}

core/src/main/java/org/springframework/security/jackson2/UnmodifiableListDeserializer.java

@@ -16,43 +16,28 @@
 
 package org.springframework.security.jackson2;
 
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.DeserializationContext;
-import com.fasterxml.jackson.databind.JsonDeserializer;
-import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.node.ArrayNode;
-
 /**
- * Custom deserializer for {@link UnmodifiableListDeserializer}.
+ * Custom deserializer for {@link UnmodifiableListMixin}.
  *
  * @author Rob Winch
+ * @author Hyunmin Choi
  * @since 5.0.2
  * @see UnmodifiableListMixin
  */
-class UnmodifiableListDeserializer extends JsonDeserializer<List> {
+class UnmodifiableListDeserializer extends AbstractUnmodifiableCollectionDeserializer<List> {
 
 	@Override
-	public List deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
-		ObjectMapper mapper = (ObjectMapper) jp.getCodec();
-		JsonNode node = mapper.readTree(jp);
+	protected List createUnmodifiableCollection(JsonNode node, ObjectMapper mapper) throws IOException {
 		List<Object> result = new ArrayList<>();
-		if (node != null) {
-			if (node instanceof ArrayNode arrayNode) {
-				for (JsonNode elementNode : arrayNode) {
-					result.add(mapper.readValue(elementNode.traverse(mapper), Object.class));
-				}
-			}
-			else {
-				result.add(mapper.readValue(node.traverse(mapper), Object.class));
-			}
-		}
+		addElements(node, mapper, result);
 		return Collections.unmodifiableList(result);
 	}
 

core/src/main/java/org/springframework/security/jackson2/UnmodifiableSetDeserializer.java

@@ -16,43 +16,28 @@
 
 package org.springframework.security.jackson2;
 
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
 import java.io.IOException;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.DeserializationContext;
-import com.fasterxml.jackson.databind.JsonDeserializer;
-import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.node.ArrayNode;
-
 /**
  * Custom deserializer for {@link UnmodifiableSetMixin}.
  *
  * @author Jitendra Singh
+ * @author Hyunmin Choi
  * @since 4.2
  * @see UnmodifiableSetMixin
  */
-class UnmodifiableSetDeserializer extends JsonDeserializer<Set> {
+class UnmodifiableSetDeserializer extends AbstractUnmodifiableCollectionDeserializer<Set> {
 
 	@Override
-	public Set deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
-		ObjectMapper mapper = (ObjectMapper) jp.getCodec();
-		JsonNode node = mapper.readTree(jp);
+	protected Set createUnmodifiableCollection(JsonNode node, ObjectMapper mapper) throws IOException {
 		Set<Object> resultSet = new HashSet<>();
-		if (node != null) {
-			if (node instanceof ArrayNode arrayNode) {
-				for (JsonNode elementNode : arrayNode) {
-					resultSet.add(mapper.readValue(elementNode.traverse(mapper), Object.class));
-				}
-			}
-			else {
-				resultSet.add(mapper.readValue(node.traverse(mapper), Object.class));
-			}
-		}
+		addElements(node, mapper, resultSet);
 		return Collections.unmodifiableSet(resultSet);
 	}