Add extra safety to unmarshaling to enums.

Removes existing TravelModeAdapter, AddressTypeAdapter and AddressComponentTypeAdapter, replaces them with generic SafeEnumAdapter.

Add tests that check converting UNKNOWN to a UrlValue throws an exception.

src/main/java/com/google/maps/internal/OkHttpPendingResult.java

@@ -21,11 +21,7 @@
 import com.google.maps.PendingResult;
 import com.google.maps.errors.ApiException;
 import com.google.maps.errors.OverQueryLimitException;
-import com.google.maps.model.AddressComponentType;
-import com.google.maps.model.AddressType;
-import com.google.maps.model.Distance;
-import com.google.maps.model.Duration;
-import com.google.maps.model.TravelMode;
+import com.google.maps.model.*;
 
 import com.squareup.okhttp.Call;
 import com.squareup.okhttp.Callback;
@@ -207,12 +203,14 @@ private T parseResponse(OkHttpPendingResult<T, R> request, Response response) th
     }
 
     Gson gson = new GsonBuilder()
-        .registerTypeAdapter(AddressComponentType.class, new AddressComponentTypeAdapter())
-        .registerTypeAdapter(AddressType.class, new AddressTypeAdapter())
         .registerTypeAdapter(DateTime.class, new DateTimeAdapter())
         .registerTypeAdapter(Distance.class, new DistanceAdapter())
         .registerTypeAdapter(Duration.class, new DurationAdapter())
-        .registerTypeAdapter(TravelMode.class, new TravelModeAdapter())
+        .registerTypeAdapter(AddressComponentType.class,
+              new SafeEnumAdapter<>(AddressComponentType.UNKNOWN))
+        .registerTypeAdapter(AddressType.class, new SafeEnumAdapter<>(AddressType.UNKNOWN))
+        .registerTypeAdapter(TravelMode.class, new SafeEnumAdapter<>(TravelMode.UNKNOWN))
+        .registerTypeAdapter(LocationType.class, new SafeEnumAdapter<>(LocationType.UNKNOWN))
         .setFieldNamingPolicy(fieldNamingPolicy)
         .create();
 

src/main/java/com/google/maps/internal/SafeEnumAdapter.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ *
+ * 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
+ *
+ *     http://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 com.google.maps.internal;
+
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+import java.util.Locale;
+import java.util.logging.Logger;
+
+/**
+ * A {@link com.google.gson.TypeAdapter} that maps case-insensitive values to an enum type. If the
+ * value is not found, an UNKNOWN value is returned, and logged. This allows the server to return
+ * values this client doesn't yet know about.
+ * @param <E> the enum type to map values to.
+ */
+public class SafeEnumAdapter<E extends Enum<E>> extends TypeAdapter<E> {
+
+  private static Logger log = Logger.getLogger(SafeEnumAdapter.class.getName());
+
+  private final Class<E> clazz;
+  private final E unknownValue;
+
+  /**
+   * @param unknownValue the value to return if the value cannot be found.
+   */
+  public SafeEnumAdapter(E unknownValue) {
+    if (unknownValue == null) throw new IllegalArgumentException();
+
+    this.unknownValue = unknownValue;
+    this.clazz = unknownValue.getDeclaringClass();
+  }
+
+  @Override
+  public void write(JsonWriter out, E value) throws IOException {
+    throw new UnsupportedOperationException("Unimplemented method");
+  }
+
+  @Override
+  public E read(JsonReader reader) throws IOException {
+    if (reader.peek() == JsonToken.NULL) {
+      reader.nextNull();
+      return null;
+    }
+    String value = reader.nextString();
+    try {
+      return Enum.valueOf(clazz, value.toUpperCase(Locale.ENGLISH));
+    } catch (IllegalArgumentException iae) {
+      log.warning(String.format("Unknown type for enum %s: '%s'", clazz.getName(), value));
+      return unknownValue;
+    }
+  }
+}