add support for gson serialization

README.md

@@ -278,6 +278,20 @@ public class HardDisk implements Serializable {
 }
 ```
 
+#### GSON
+
+Use a [GSON](https://github.com/google/gson) serializer/deserializer like this:
+
+```java
+import static wtf.metio.storageunits.gson.*;
+
+new GsonBuilder()
+        .registerTypeHierarchyAdapter(StorageUnit.class, new StorageUnitSerializer())
+        .registerTypeHierarchyAdapter(StorageUnit.class, new BinaryStorageUnitDeserializer())
+        .registerTypeHierarchyAdapter(StorageUnit.class, new DecimalStorageUnitDeserializer())
+        .create();
+```
+
 #### Jackson
 
 Use the provided `StorageUnitModule` like this:
@@ -394,6 +408,14 @@ To use this project just declare the following dependency inside your POM:
     </dependency>
     <!-- EclipseLink ONLY -->
 
+    <!-- GSON ONLY -->
+    <dependency>
+        <groupId>wtf.metio.storage-units</groupId>
+        <artifactId>storage-units-gson</artifactId>
+        <version>${version.storage-units}</version>
+    </dependency>
+    <!-- GSON ONLY -->
+
     <!-- Jackson ONLY -->
     <dependency>
         <groupId>wtf.metio.storage-units</groupId>

pom.xml

@@ -42,6 +42,7 @@
     <modules>
         <module>storage-units-dozer</module>
         <module>storage-units-eclipselink</module>
+        <module>storage-units-gson</module>
         <module>storage-units-jackson</module>
         <module>storage-units-jakarta</module>
         <module>storage-units-mapstruct</module>

storage-units-gson/pom.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ SPDX-FileCopyrightText: The Storage-Units Authors
+  ~ SPDX-License-Identifier: 0BSD
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!--                                  PARENT                                 -->
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!-- https://maven.apache.org/pom.html#Inheritance -->
+    <parent>
+        <groupId>wtf.metio.storage-units</groupId>
+        <artifactId>storage-units.java</artifactId>
+        <version>9999.99.99-SNAPSHOT</version>
+    </parent>
+
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!--                               COORDINATES                               -->
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!-- https://maven.apache.org/pom.html#Maven_Coordinates -->
+    <artifactId>storage-units-gson</artifactId>
+
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!--                               INFORMATIONS                              -->
+    <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+    <!-- https://maven.apache.org/pom.html#More_Project_Information -->
+    <name>Storage Units :: GSON</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>wtf.metio.storage-units</groupId>
+            <artifactId>storage-units-model</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+        </dependency>
+    </dependencies>
+</project>

storage-units-gson/src/main/java/module-info.java

@@ -0,0 +1,15 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+/**
+ * Module for GSON support.
+ */
+@org.jspecify.nullness.NullMarked
+module wtf.metio.storageunits.gson {
+
+    requires wtf.metio.storageunits.model;
+    requires com.google.gson;
+    requires org.jspecify;
+
+}

storage-units-gson/src/main/java/wtf/metio/storageunits/gson/BinaryStorageUnitDeserializer.java

@@ -0,0 +1,29 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import wtf.metio.storageunits.model.StorageUnit;
+import wtf.metio.storageunits.model.StorageUnits;
+
+import java.lang.reflect.Type;
+
+/**
+ * Deserializes value back into binary storage units.
+ */
+public final class BinaryStorageUnitDeserializer implements JsonDeserializer<StorageUnit<?>> {
+
+    @Override
+    public StorageUnit<?> deserialize(
+            final JsonElement json,
+            final Type typeOfT,
+            final JsonDeserializationContext context) throws JsonParseException {
+        return StorageUnits.parse(json.getAsJsonPrimitive().getAsString()).asBestMatchingBinaryUnit();
+    }
+
+}

storage-units-gson/src/main/java/wtf/metio/storageunits/gson/DecimalStorageUnitDeserializer.java

@@ -0,0 +1,29 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import wtf.metio.storageunits.model.StorageUnit;
+import wtf.metio.storageunits.model.StorageUnits;
+
+import java.lang.reflect.Type;
+
+/**
+ * Deserializes value back into decimal storage units.
+ */
+public final class DecimalStorageUnitDeserializer implements JsonDeserializer<StorageUnit<?>> {
+
+    @Override
+    public StorageUnit<?> deserialize(
+            final JsonElement json,
+            final Type typeOfT,
+            final JsonDeserializationContext context) throws JsonParseException {
+        return StorageUnits.parse(json.getAsJsonPrimitive().getAsString()).asBestMatchingDecimalUnit();
+    }
+
+}

storage-units-gson/src/main/java/wtf/metio/storageunits/gson/StorageUnitSerializer.java

@@ -0,0 +1,29 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import wtf.metio.storageunits.model.StorageUnit;
+
+import java.lang.reflect.Type;
+
+/**
+ * Serializes storage units into strings.
+ */
+public final class StorageUnitSerializer implements JsonSerializer<StorageUnit<?>> {
+
+    @Override
+    public JsonElement serialize(
+            final StorageUnit<?> src,
+            final Type typeOfSrc,
+            final JsonSerializationContext context) {
+        return new JsonPrimitive(src.inByte().toString());
+    }
+
+}

storage-units-gson/src/main/java/wtf/metio/storageunits/gson/package-info.java

@@ -0,0 +1,10 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+/**
+ * Serialization support for GSON.
+ *
+ * @see <a href="https://github.com/google/gson">GSON Homepage</a>
+ */
+package wtf.metio.storageunits.gson;

storage-units-gson/src/test/java/wtf/metio/storageunits/gson/BinaryDeserializationTest.java

@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import wtf.metio.storageunits.model.StorageUnit;
+
+class BinaryDeserializationTest {
+
+    private Gson gson;
+
+    @BeforeEach
+    void setUp() {
+        gson = new GsonBuilder()
+                .registerTypeHierarchyAdapter(StorageUnit.class, new BinaryStorageUnitDeserializer())
+                .create();
+    }
+
+    @Test
+    void deserializeStorageUnit() {
+        // given
+        final String input = "1024";
+
+        // when
+        final StorageUnit<?> unit = gson.fromJson(input, StorageUnit.class);
+
+        // then
+        Assertions.assertEquals("1.00 KiB", unit.toString());
+    }
+
+}

storage-units-gson/src/test/java/wtf/metio/storageunits/gson/DecimalDeserializationTest.java

@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import wtf.metio.storageunits.model.StorageUnit;
+
+class DecimalDeserializationTest {
+
+    private Gson gson;
+
+    @BeforeEach
+    void setUp() {
+        gson = new GsonBuilder()
+                .registerTypeHierarchyAdapter(StorageUnit.class, new DecimalStorageUnitDeserializer())
+                .create();
+    }
+
+    @Test
+    void deserializeStorageUnit() {
+        // given
+        final String input = "1000";
+
+        // when
+        final StorageUnit<?> unit = gson.fromJson(input, StorageUnit.class);
+
+        // then
+        Assertions.assertEquals("1.00 kB", unit.toString());
+    }
+
+}

storage-units-gson/src/test/java/wtf/metio/storageunits/gson/StorageUnitSerializerTest.java

@@ -0,0 +1,52 @@
+/*
+ * SPDX-FileCopyrightText: The Storage-Units Authors
+ * SPDX-License-Identifier: 0BSD
+ */
+
+package wtf.metio.storageunits.gson;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import wtf.metio.storageunits.model.Kibibyte;
+import wtf.metio.storageunits.model.StorageUnit;
+import wtf.metio.storageunits.model.StorageUnits;
+
+class StorageUnitSerializerTest {
+
+    private Gson gson;
+
+    @BeforeEach
+    void setUp() {
+        gson = new GsonBuilder()
+                .registerTypeHierarchyAdapter(StorageUnit.class, new StorageUnitSerializer())
+                .create();
+    }
+
+    @Test
+    void serializeStorageUnit() {
+        // given
+        final StorageUnit<?> unit = StorageUnits.kibibyte(1L);
+
+        // when
+        final String output = gson.toJson(unit);
+
+        // then
+        Assertions.assertEquals("\"1024\"", output);
+    }
+
+    @Test
+    void serializeNonStorageUnit() {
+        // given
+        final String input = "abc";
+
+        // when
+        final String output = gson.toJson(input);
+
+        // then
+        Assertions.assertEquals("\"abc\"", output);
+    }
+
+}