/*
* Copyright 2013 MovingBlocks
*
* 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 org.terasology.utilities.gson;
import com.google.common.collect.Maps;
import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;
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.Map;
/**
* A Gson Adapter factory for supporting enums in a case-insensitive manner
*
*/
public class CaseInsensitiveEnumTypeAdapterFactory implements TypeAdapterFactory {
@Override
public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
Class<T> rawType = (Class<T>) type.getRawType();
if (!rawType.isEnum()) {
return null;
}
final Map<String, T> lowercaseToConstant = Maps.newHashMap();
for (T constant : rawType.getEnumConstants()) {
String norm = normalize(constant.toString());
lowercaseToConstant.put(norm, constant);
}
return new TypeAdapter<T>() {
@Override
public void write(JsonWriter out, T value) throws IOException {
if (value == null) {
out.nullValue();
} else {
out.value(normalize(value.toString()));
}
}
@Override
public T read(JsonReader reader) throws IOException {
if (reader.peek() == JsonToken.NULL) {
reader.nextNull();
return null;
} else {
String value = reader.nextString();
return lowercaseToConstant.get(normalize(value));
}
}
};
}
private String normalize(String name) {
return name.toLowerCase(Locale.ENGLISH);
}
}