Refactor serialization adapter retrieval by version

nullaway/src/main/java/com/uber/nullaway/fixserialization/FixSerializationConfig.java

@@ -24,8 +24,6 @@
 
 import com.google.common.base.Preconditions;
 import com.uber.nullaway.fixserialization.adapters.SerializationAdapter;
-import com.uber.nullaway.fixserialization.adapters.SerializationV1Adapter;
-import com.uber.nullaway.fixserialization.adapters.SerializationV3Adapter;
 import com.uber.nullaway.fixserialization.out.SuggestedNullableFixInfo;
 import java.io.IOException;
 import java.nio.file.Files;
@@ -86,7 +84,9 @@ public FixSerializationConfig(
     this.suggestEnclosing = suggestEnclosing;
     this.fieldInitInfoEnabled = fieldInitInfoEnabled;
     this.outputDirectory = outputDirectory;
-    serializer = new Serializer(this, initializeAdapter(SerializationAdapter.LATEST_VERSION));
+    serializer =
+        new Serializer(
+            this, SerializationAdapter.getAdapterForVersion(SerializationAdapter.LATEST_VERSION));
   }
 
   /**
@@ -126,32 +126,11 @@ public FixSerializationConfig(String configFilePath, int serializationVersion) {
         XMLUtil.getValueFromAttribute(
                 document, "/serialization/fieldInitInfo", "active", Boolean.class)
             .orElse(false);
-    SerializationAdapter serializationAdapter = initializeAdapter(serializationVersion);
+    SerializationAdapter serializationAdapter =
+        SerializationAdapter.getAdapterForVersion(serializationVersion);
     serializer = new Serializer(this, serializationAdapter);
   }
 
-  /**
-   * Initializes NullAway serialization adapter according to the requested serialization version.
-   */
-  private SerializationAdapter initializeAdapter(int version) {
-    switch (version) {
-      case 1:
-        return new SerializationV1Adapter();
-      case 2:
-        throw new RuntimeException(
-            "Serialization version v2 is skipped and was used for an alpha version of the auto-annotator tool. Please use version 3 instead.");
-      case 3:
-        return new SerializationV3Adapter();
-      default:
-        throw new RuntimeException(
-            "Unrecognized NullAway serialization version: "
-                + version
-                + ". Supported versions: 1 to "
-                + SerializationAdapter.LATEST_VERSION
-                + ".");
-    }
-  }
-
   public @Nullable Serializer getSerializer() {
     return serializer;
   }

nullaway/src/main/java/com/uber/nullaway/fixserialization/adapters/SerializationAdapter.java

@@ -71,4 +71,29 @@
    * @return The serialized method symbol.
    */
   String serializeMethodSignature(Symbol.MethodSymbol methodSymbol);
+
+  /**
+   * Gets the adapter for the given version number.
+   *
+   * @param version Version number of the adapter.
+   * @return Adapter for the given version.
+   */
+  static SerializationAdapter getAdapterForVersion(int version) {
+    switch (version) {
+      case 1:
+        return new SerializationV1Adapter();
+      case 2:
+        throw new RuntimeException(
+            "Serialization version v2 is skipped and was used for an alpha version of the auto-annotator tool. Please use version 3 instead.");
+      case 3:
+        return new SerializationV3Adapter();
+      default:
+        throw new RuntimeException(
+            "Unrecognized NullAway serialization version: "
+                + version
+                + ". Supported versions: 1 to "
+                + SerializationAdapter.LATEST_VERSION
+                + ".");
+    }
+  }
 }