example of Gson serialize and deserialize

arnesacnussem · arnesacnussem · commit 5b4e7045c750 · 2021-05-31T16:47:45.000+08:00
diff --git a/java-diff-utils/pom.xml b/java-diff-utils/pom.xml
@@ -24,6 +24,25 @@
             <artifactId>assertj-core</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.8.7</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-core</artifactId>
+            <version>2.12.3</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.12.3</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
diff --git a/java-diff-utils/src/test/java/com/github/difflib/examples/GsonSerializeTest.java b/java-diff-utils/src/test/java/com/github/difflib/examples/GsonSerializeTest.java
@@ -0,0 +1,77 @@
+package com.github.difflib.examples;
+
+import com.github.difflib.DiffUtils;
+import com.github.difflib.TestConstants;
+import com.github.difflib.patch.*;
+import com.google.gson.*;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.List;
+
+import static com.github.difflib.GenerateUnifiedDiffTest.fileToLines;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+public class GsonSerializeTest {
+    List<String> origLines = fileToLines(TestConstants.MOCK_FOLDER + "original.txt");
+    List<String> revLines = fileToLines(TestConstants.MOCK_FOLDER + "revised.txt");
+
+    public GsonSerializeTest() throws IOException {
+    }
+
+    @Test
+    public void serialize() {
+        Patch<String> diff = DiffUtils.diff(origLines, revLines);
+        String json = new Gson().toJson(diff);
+        System.out.println(json);
+    }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    public void deserialize() throws PatchFailedException {
+        Patch<String> diff = DiffUtils.diff(origLines, revLines);
+        String json = new Gson().toJson(diff);
+        Patch<String> patch = new GsonBuilder()
+                .registerTypeAdapter(Chunk.class, new ChunkDeserializer())
+                .registerTypeAdapter(AbstractDelta.class, new AbstractDeltaDeserializer())
+                .registerTypeAdapter(ConflictOutput.class, (JsonDeserializer<ConflictOutput<String>>) (_ignored1, _ignored2, _ignored3) -> null)
+                .create()
+                .fromJson(json, Patch.class);
+        assertThat(patch.applyTo(origLines)).isEqualTo(revLines);
+    }
+
+    public static class AbstractDeltaDeserializer implements JsonDeserializer<AbstractDelta<String>> {
+
+        @Override
+        public AbstractDelta<String> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+            JsonObject object = json.getAsJsonObject();
+            DeltaType type = DeltaType.valueOf(object.get("type").getAsString());
+            Chunk<String> source = context.deserialize(object.get("source"), Chunk.class);
+            Chunk<String> target = context.deserialize(object.get("target"), Chunk.class);
+            switch (type) {
+                case EQUAL:
+                    return new EqualDelta<>(source, target);
+                case INSERT:
+                    return new InsertDelta<>(source, target);
+                case DELETE:
+                    return new DeleteDelta<>(source, target);
+                case CHANGE:
+                    return new ChangeDelta<>(source, target);
+            }
+            return null;
+        }
+    }
+
+    public static class ChunkDeserializer implements JsonDeserializer<Chunk<String>> {
+
+        @Override
+        public Chunk<String> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+            JsonObject object = json.getAsJsonObject();
+            int position = object.get("position").getAsInt();
+            List<String> lines = context.deserialize(object.get("lines"), List.class);
+            List<Integer> changePosition = context.deserialize(object.get("changePosition"), List.class);
+            return new Chunk<>(position, lines, changePosition);
+        }
+    }
+}
