package com.pubnub.api.utils;

import com.google.gson.JsonDeserializationContext;

import com.google.gson.JsonDeserializer;

import com.google.gson.JsonElement;

import com.google.gson.JsonObject;

import com.google.gson.JsonParseException;

import java.lang.reflect.Type;

public class UnwrapSingleField<T> implements JsonDeserializer<T> {

@Override

public T deserialize(final JsonElement json, final Type typeOfT, final JsonDeserializationContext context) throws JsonParseException {

final JsonObject jsonObject = json.getAsJsonObject();

if (jsonObject.keySet().size() != 1) {

throw new IllegalStateException("Couldn't unwrap field for object containing more than 1 field. Actual number of fields: " + jsonObject.keySet().size());

}

final String key = jsonObject.keySet().toArray(new String[]{})[0];

final JsonElement element = jsonObject.get(key);

return context.deserialize(element, typeOfT);

}

}