# Gson Enum parsing



## mavinatic (18. Mai 2015)

Hallo Community,

ich möchte meinen JSON-String in ein Message.class Objekt konvertieren lassen, dabei wird aber mein Enum OperationType.class nicht gemappet. Ich habe einen JsonDeserialize...geschrieben, jedoch funktioniert das damit auch nicht. :-( habt ihr einen Tipp?


```
public class Message
{
	private HashMap<String, String> parameters = new HashMap<String, String>();
	private OperationType operationType = null;
	private String result = null;

	public Message(OperationType operationType,
			HashMap<String, String> parameters)
	{
		this.operationType = operationType;
		this.parameters = parameters;
	}

	public void setParameters(HashMap<String, String> parameters)
	{
		this.parameters = parameters;
	}

	public HashMap<String, String> getParameters() {
		return this.parameters;
	}
	
	public OperationType getOperationType() {
		return this.operationType;
	}
	
	public String getResult() {
		return this.result;
	}
	
	public void setResult(String s) {
		this.result = s;
	}
}
```


```
public enum OperationType
{
	ENTITY_REGISTER,
	ENTITY_POSITIONS,
	ENTITY_SHOOT,
	ENTITY_MOVE,
	ENTITY_DELETE;
	

}
```


```
package com.george.server.parser;

import java.lang.reflect.Type;
import java.util.HashMap;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;

public class JSONMessageParser extends AbstractMessageParser {
	private GsonBuilder gsonBuilder = new GsonBuilder();
	private Gson gson = null;
	
	public JSONMessageParser() {
		JsonDeserializer<?> jd = new JsonDeserializer<OperationType>() {

			@Override
			public OperationType deserialize(JsonElement arg0, Type arg1,
					JsonDeserializationContext arg2) throws JsonParseException {
				String value = arg0.getAsString();
				
				OperationType operationType = null;
				System.out.println("VALUE: " + value);
				switch(value)
				{
					case "EntityRegister":
						operationType = OperationType.ENTITY_REGISTER;
						break;
					case "EntityPositions":
						operationType = OperationType.ENTITY_POSITIONS;
						break;
					case "EntityShoot":
						operationType = OperationType.ENTITY_SHOOT;
						break;
					case "EntityMove":
						operationType = OperationType.ENTITY_MOVE;
						break;
					case "EntityDelete":
						operationType = OperationType.ENTITY_DELETE;
						break;
				}
				
				return operationType;
			}
		};
		
		this.gson = this.gsonBuilder.registerTypeAdapter(OperationType.class, jd).create();
	}
	
	@Override
	public boolean isMessageParserSupported(String message) {
		if (message.contains("{") || message.contains("}")
				|| message.contains("[") || message.contains("]")) {
			return true;
		}

		return false;
	}

	@Override
	public Message parseIncomingMessage(String message) {
		System.out.println(message);

		Message m = gson.fromJson(message, Message.class);
		
		return null;
	}

	@Override
	public String parseOutgoingMessage(Message message) {
		return null;
	}
	
	public static void main(String[] args) {
		JSONMessageParser j = new JSONMessageParser();
		j.parseIncomingMessage("{\"operation\": \"" + OperationType.ENTITY_DELETE + "\", \"parameters\": {\"id\": \"1\"}}");
	}
}
```


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