Android Open Source - android-http Base Gson Handler

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License

The source code is released under:

Apache License

Java Source Code

package com.markom.android.http.handler;
/* w ww  . j  a  v  a2 s . com*/
import org.apache.http.Header;

import com.loopj.android.http.AsyncHttpResponseHandler;
import com.markom.android.http.exceptions.GsonParsingException;
import com.markom.android.http.exceptions.ParsingNotImplementedException;
import com.markom.android.http.model.ServiceResponse;
import com.markom.android.http.parser.GSONParser;

/**
 * Extends {@link AsyncHttpResponseHandler} and represent base Gson handler class that contains {@link ServiceResponse}
 * object callbacks together with concrete object callbacks.
 * <p>
 * Extending this abstract class requires implementing {@link BaseGsonHandler#parseServiceResponse(String)} method that
 * returns {@link ServiceResponse} or any of it's subclasses. Basic parsing is implemented inside of
 * {@link BaseClassHandler} for simple objects or {@link BaseGenericHandler} for collection's. For custom json schema
 * extend {@link ServiceResponse} class and either {@link BaseClassHandler} or {@link BaseGenericHandler}, and override
 * parsing method.
 * 
 * @param <T> generic type of data encapsulated by {@link ServiceResponse}.
 * 
 * @see {@link BaseClassHandler}, {@link BaseGenericHandler}, {@link ServiceResponse}
 * 
 * @author Marko Milos
 */
public abstract class BaseGsonHandler<T> extends AsyncHttpResponseHandler {

  /**
   * Create {@link ServiceResponse} or any of it's subclasses from string response data. Use {@link GSONParser}
   * methods to create objects from json string.
   * 
   * @param response raw response data as string
   * @return {@link ServiceResponse} kind of object.
   * @throws GsonParsingException thrown when gson parsing fails.
   */
  protected abstract ServiceResponse<T> parseServiceResponse(String response) throws GsonParsingException;

  /**
   * Called when request is finished succefully.
   * 
   * @param result requested data.
   */
  public void onSuccess(T result) {
  }

  /**
   * Called when request is finished succefully.
   * 
   * @param statusCode the status code of the response.
   * @param result requested data.
   */
  public void onSuccess(int statusCode, T result) {
    onSuccess(result);
  }

  /**
   * Called when request is finished succefully.
   * 
   * @param statusCode the status code of the response.
   * @param headers the headers of the HTTP response.
   * @param result requested data.
   */
  public void onSuccess(int statusCode, Header[] headers, T result) {
    onSuccess(statusCode, result);
  }

  /**
   * Called when request is finished succefully.
   * 
   * @param result {@link ServiceResponse} containing requested data.
   */
  public void onSuccess(ServiceResponse<T> result) {
  }

  /**
   * Called when request is finished succefully.
   * 
   * @param statusCode the status code of the response.
   * @param result {@link ServiceResponse} containing requested data.
   */
  public void onSuccess(int statusCode, ServiceResponse<T> result) {
    onSuccess(result);
  }

  /**
   * Called when request is finished succefully.
   * 
   * @param statusCode the status code of the response.
   * @param headers the headers of the HTTP response.
   * @param result {@link ServiceResponse} containing requested data.
   */
  public void onSuccess(int statusCode, Header[] headers, ServiceResponse<T> result) {
    onSuccess(statusCode, headers, result.getData());
    onSuccess(statusCode, result);
  }

  @Override
  public void onSuccess(int statusCode, Header[] headers, String content) {
    handleJsonResponse(statusCode, headers, content);
  }

  /**
   * Handles response string calling parsing method and appropriate callback methods.
   * 
   * @param statusCode the status code of the response.
   * @param headers the headers of the HTTP response.
   * @param response raw response data.
   */
  private void handleJsonResponse(int statusCode, Header[] headers, String response) {
    try {
      // Try to parse response.
      ServiceResponse<T> serviceResponse = parseServiceResponse(response);

      // Check if there is existing service response object
      if (serviceResponse != null) {

        // Check if there is existing data enapsulated by service response object
        // data can be null when empty string is retuned as response ""
        if (serviceResponse.getData() != null) {

          // Everything is parsed well, call success calbacks
          super.onSuccess(statusCode, headers, response);
          onSuccess(statusCode, headers, serviceResponse);

        } else {
          // There is no data. Error happened during parsing process trigger error
          onFailure(new GsonParsingException(), response);
        }

      } else {
        // ServiceResponse is null, parsing is not implemented trigger error
        onFailure(new ParsingNotImplementedException(), response);
      }
    } catch (GsonParsingException e) {
      // Error triggered while parsing response
      onFailure(e, response);
    }
  }

}

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