# HttpException - Way to deal with Error Codes
###### tags: `Android Code Sample`


[TOC]

# Error Code
Can use [@IntDef](/cCkssEPkTqiSlhjbOvMX9A) to state all Error Codes, and by using annotation, we can make development much more readable and get a note on errors right away in the process.

# Error Exception Factory
We can make a factory and deal all errors here. In order to have a widely used Exception as return, we have to make a class, in this case **HttpException**.

## **Our own HttpException Class:**

public class HttpException {
    private int code;
    private String displayMsg;
    private Throwable throwable;

    public HttpException(Throwable e) { throwable = e; }

    public HttpException(Throwable throwable, int code, String displayMsg){
        this.throwable = throwable;
        this.displayMsg = displayMsg;
        this.code = code;
    }

    //Setter
    public void setCode(int code) {
        this.code = code;
    }

    public void setDisplayMsg(String displayMsg) {
        this.displayMsg = displayMsg;
    }

    //Getter
    public int getCode() {
        return code;
    }

    public String getDisplayMsg() {
        return displayMsg;
    }
}

## **ExceptionFactory Example:**
**CodeException** is a class made with @IntDef. (For more can check Error Code Section).

import org.json.JSONException;
import java.net.ConnectException;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;

public class ExceptionFactory {
    private static final String HTTP_EXCEPTION_ERROR = "Network Error";
    private static final String CONNECTION_ERROR = "Connection Error";
    private static final String JSON_ERROR = "Fail to parse data";
    private static final String UNKNOWN_HOST_ERROR = "Recheck your network status";

    public static HttpException checkException(Throwable e){
        HttpException dealException = new HttpException(e);

        if (e instanceof RuntimeException) {
            RuntimeException exception = (RuntimeException) e;
            dealException.setCode(CodeException.RUNTIME_ERROR);
            dealException.setDisplayMsg(exception.getMessage());
        } else if (e instanceof ConnectException ||e instanceof SocketTimeoutException) {
            dealException.setCode(CodeException.HTTP_ERROR);
            dealException.setDisplayMsg(CONNECTION_ERROR);
        } else if (e instanceof JSONException) { // || e instanceof ParseException (part of runtimeException
            dealException.setCode(CodeException.JSON_ERROR);
            dealException.setDisplayMsg(JSON_ERROR);
        }else if (e instanceof UnknownHostException){
            dealException.setCode(CodeException.UNKNOWN_HOST_ERROR);
            dealException.setDisplayMsg(UNKNOWN_HOST_ERROR);
        }else if(e != null){ // instanceof Throwable
            dealException.setCode(CodeException.OTHER_ERROR);
            dealException.setDisplayMsg(e.getMessage());
        }else {
            dealException.setCode(CodeException.NETWORK_ERROR);
            dealException.setDisplayMsg(HTTP_EXCEPTION_ERROR);
        }
        return dealException;
    }
}

## Factory usage display

@Override
public void onError(Throwable e) {
    e.printStackTrace();
    onError(FactoryException.checkException(e));
}