HashMapSerializer.java

package org.topdank.cfide.io.gson;

import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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 com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.gson.reflect.TypeToken;

@SuppressWarnings({ "rawtypes", "unchecked" })
public class HashMapSerializer implements JsonSerializer<HashMap>, JsonDeserializer<HashMap> {

	@Override
	public HashMap deserialize(JsonElement e, Type type, JsonDeserializationContext context) throws JsonParseException {
		try {
			JsonObject obj = e.getAsJsonObject();
			Set<Entry<String, JsonElement>> elementSet = obj.entrySet();
			Map<String, Object> result = new HashMap<String, Object>(elementSet.size());
			for (Entry<String, JsonElement> outerEntry : obj.entrySet()) {
				Class<?> clazz = null;
				JsonElement valElement = null;
				for (Entry<String, JsonElement> innerEntry : outerEntry.getValue().getAsJsonObject().entrySet()) {
					if (innerEntry.getKey().equals("class")) {
						clazz = Class.forName(innerEntry.getValue().getAsString());
					} else if (innerEntry.getKey().equals("val")) {
						valElement = innerEntry.getValue();
					}
				}
				Type clazzType = TypeToken.get(clazz).getType();
				Object o = context.deserialize(valElement, clazzType);
				result.put(outerEntry.getKey(), o);
			}
			return (HashMap) result;
		} catch (Throwable t) {
			return context.deserialize(e, type);
		}
	}

	@Override
	public JsonElement serialize(HashMap map, Type type, JsonSerializationContext context) {
		JsonObject result = new JsonObject();
		for (Entry<String, Object> entry : (Set<Entry<String, Object>>) map.entrySet()) {
			JsonObject resultEntryObject = new JsonObject();
			Object toSerialiseValue = entry.getValue();
			resultEntryObject.add("class", new JsonPrimitive(toSerialiseValue.getClass().getCanonicalName()));
			resultEntryObject.add("val", context.serialize(toSerialiseValue));
			result.add(entry.getKey(), resultEntryObject);
		}
		return result;
	}
}