EnumAdaptorFactory.java

/*
 * This file is part of FTB Launcher.
 *
 * Copyright © 2012-2016, FTB Launcher Contributors <https://github.com/Slowpoke101/FTBLaunch/>
 * FTB Launcher is 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 net.feed_the_beast.launcher.json;

import java.io.IOException;
import java.util.Locale;
import java.util.Map;

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;

public class EnumAdaptorFactory implements TypeAdapterFactory
{

	@SuppressWarnings("unchecked")
	@Override
	public <T> TypeAdapter<T> create (Gson gson, TypeToken<T> type)
	{
		if (!type.getRawType().isEnum())
		{
			return null;
		}
		final Map<String, T> map = Maps.newHashMap();
		for(T c : (T[])type.getRawType().getEnumConstants())
		{
			map.put(c.toString().toLowerCase(Locale.US), c);
		}

		return new TypeAdapter<T>()
		{
			@Override
			public T read (JsonReader reader) throws IOException
			{
				if (reader.peek() == JsonToken.NULL)
				{
					reader.nextNull();
					return null;
				}
				String name = reader.nextString();
				if (name == null)
				{
					return null;
				}
				return map.get(name.toLowerCase(Locale.US));
			}

			@Override
			public void write (JsonWriter writer, T value) throws IOException
			{
				if (value == null)
				{
					writer.nullValue();
				}
				else
				{
					writer.value(value.toString().toLowerCase(Locale.US));
				}
			}
		};
	}
}