Merge pull request #32 from dandc87/ak_enum_support

EnumJsonAdapter

moshi/src/main/java/com/squareup/moshi/EnumJsonAdapter.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2014 Square, Inc.
+ *
+ * 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.squareup.moshi;
+
+import java.io.IOException;
+import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Type;
+
+/**
+ * Convert Enum types to JSON string values
+ *
+ * @param <T> Enum class to adapt
+ */
+final class EnumJsonAdapter<T extends Enum<T>> extends JsonAdapter<T> {
+  public static final Factory FACTORY = new Factory() {
+    @Override public JsonAdapter<? extends Enum> create(Type type, AnnotatedElement annotations,
+        Moshi moshi) {
+      Class<?> rawType = Types.getRawType(type);
+      if (Enum.class.isAssignableFrom(rawType)) {
+        //noinspection unchecked
+        Class<? extends Enum> enumType = (Class<? extends Enum>) rawType;
+        return new EnumJsonAdapter<>(enumType.getEnumConstants()).nullSafe();
+      }
+      return null;
+    }
+  };
+
+  private final T[] values;
+
+  private EnumJsonAdapter(T[] values) {
+    this.values = values;
+  }
+
+  @Override
+  public T fromJson(JsonReader reader) throws IOException {
+    String name = reader.nextString();
+    for (T value : values) {
+      if (value.name().equals(name)) {
+        return value;
+      }
+    }
+    return null;
+  }
+
+  @Override
+  public void toJson(JsonWriter writer, T value) throws IOException {
+    writer.value(value.name());
+  }
+}

moshi/src/main/java/com/squareup/moshi/Moshi.java

@@ -34,6 +34,7 @@ public final class Moshi {
     List<JsonAdapter.Factory> factories = new ArrayList<>();
     factories.addAll(builder.factories);
     factories.add(StandardJsonAdapters.FACTORY);
+    factories.add(EnumJsonAdapter.FACTORY);
     factories.add(CollectionJsonAdapter.FACTORY);
     factories.add(MapJsonAdapter.FACTORY);
     factories.add(ArrayJsonAdapter.FACTORY);

moshi/src/test/java/com/squareup/moshi/EnumJsonAdapterTest.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2014 Square, Inc.
+ *
+ * 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.squareup.moshi;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EnumJsonAdapterTest {
+  private final Moshi moshi = new Moshi.Builder().build();
+
+  enum Roshambo {
+    ROCK,
+    PAPER,
+    SCISSORS
+  }
+
+  @Test public void basics() throws Exception {
+    JsonAdapter<Roshambo> adapter = moshi.adapter(Roshambo.class).lenient();
+    assertThat(adapter.fromJson("\"ROCK\"")).isEqualTo(Roshambo.ROCK);
+    assertThat(adapter.toJson(Roshambo.PAPER)).isEqualTo("\"PAPER\"");
+  }
+
+  @Test public void invalidInput() throws Exception {
+    JsonAdapter<Roshambo> adapter = moshi.adapter(Roshambo.class).lenient();
+    assertThat(adapter.fromJson("\"Lizard\"")).isNull();
+    assertThat(adapter.fromJson("\"SPOCK\"")).isNull();
+  }
+
+  @Test public void nulls() throws Exception {
+    JsonAdapter<Roshambo> adapter = moshi.adapter(Roshambo.class).lenient();
+    assertThat(adapter.fromJson("null")).isNull();
+    assertThat(adapter.toJson(null)).isEqualTo("null");
+  }
+}