CmClient.java

import org.json.simple.JSONObject;

class CmClient
{
    private String cmServerUrl;

    public CmClient(String url)
    {
        cmServerUrl = url;
    }

    // returns category id if success, negative integer otherwise
    public long authenticateCategory(String user, String password, String category)
        throws java.io.IOException
    {
        JsonHttpClient client = new JsonHttpClient();

        JSONObject content = new JSONObject();
        content.put("login", user);
        content.put("password", password);
        content.put("category", category);

        JSONObject result = client.post(cmServerUrl + "/authenticate_category", content);

        Object resultContent = result.get("content");
        long categoryId = -1;
        if (resultContent != null)
        {
            categoryId =
                ((Long)(((JSONObject)resultContent).get("category_id"))).longValue();
        }

        return categoryId;
    }

    public boolean isUserExist(String user)
        throws java.io.IOException
    {
        JsonHttpClient client = new JsonHttpClient();
        JSONObject result = client.get(cmServerUrl + "/users/" + user);
        int statusCode = ((Integer)result.get("status")).intValue();

        return statusCode == 200;
    }
}