Volley Authentication Request

import android.util.Base64;

import com.android.volley.AuthFailureError;
import com.android.volley.Response;
import com.android.volley.toolbox.StringRequest;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by Glenn on 8/25/2016.
 */
public class AuthStringRequest extends StringRequest {

    private String username, password, token;

    public AuthStringRequest(int method, String url, Response.Listener<String> listener, Response.ErrorListener errorListener) {
        super(method, url, listener, errorListener);
    }

    public AuthStringRequest(String url, Response.Listener<String> listener, Response.ErrorListener errorListener) {
        super(url, listener, errorListener);
    }

    public void prepareHeader(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public void prepareHeader(String token) {
        this.token = token;
    }

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        Map<String, String> headers = new HashMap<String, String>();
        String credentials, auth;
        if(token.isEmpty()) {
            credentials = username + ":" + password;
            auth = "Basic "
                    + Base64.encodeToString(credentials.getBytes(), Base64.NO_WRAP);
        } else {
            credentials = token;
            auth = "Bearer "
                    + Base64.encodeToString(credentials.getBytes(), Base64.NO_WRAP);
        }
        headers.put("Content-Type", "application/json");
        headers.put("Authorization", auth);
        return headers;
    }
}