Java tutorial
/* Android Asynchronous Http Client Copyright (c) 2011 James Smith <james@loopj.com> http://loopj.com Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package com.cloudsynch.quickshare.http; import java.io.IOException; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.HttpResponseException; import org.apache.http.entity.BufferedHttpEntity; import org.apache.http.util.EntityUtils; import android.os.Handler; import android.os.Looper; import android.os.Message; import com.cloudsynch.quickshare.netresources.Result; import com.cloudsynch.quickshare.netresources.ResultParser; /** * Used to intercept and handle the responses from requests made using * {@link AsyncHttpClient}. The {@link #onSuccess(String)} method is designed to * be anonymously overridden with your own response handling code. * <p> * Additionally, you can override the {@link #onFailure(Throwable, String)}, * {@link #onStart()}, and {@link #onFinish()} methods as required. * <p> * For example: * <p> * * <pre> * AsyncHttpClient client = new AsyncHttpClient(); * client.get("http://www.google.com", new AsyncHttpResponseHandler() { * @Override * public void onStart() { * // Initiated the request * } * * @Override * public void onSuccess(String response) { * // Successfully got a response * } * * @Override * public void onFailure(Throwable e, String response) { * // Response failed :( * } * * @Override * public void onFinish() { * // Completed the request (either success or failure) * } * }); * </pre> */ public class AsyncHttpResponseHandler<T> { protected static final int SUCCESS_MESSAGE = 0; protected static final int FAILURE_MESSAGE = 1; protected static final int START_MESSAGE = 2; protected static final int FINISH_MESSAGE = 3; private Handler handler; private ResultParser<T> mParser; public AsyncHttpResponseHandler() { } /** * Creates a new AsyncHttpResponseHandler */ public AsyncHttpResponseHandler(ResultParser<T> parser) { // Set up a handler to post events back to the correct thread if // possible mParser = parser; if (Looper.myLooper() != null) { handler = new Handler() { @Override public void handleMessage(Message msg) { AsyncHttpResponseHandler.this.handleMessage(msg); } }; } } // // Callbacks to be overridden, typically anonymously // /** * Fired when the request is started, override to handle in your own code */ public void onStart() { } /** * Fired in all cases when the request is finished, after both success and * failure, override to handle in your own code */ public void onFinish() { } /** * Fired when a request returns successfully, override to handle in your own * code * * @param content * the body of the HTTP response from the server */ public void onSuccess(Result<T> content) { } /** * Fired when a request returns successfully, override to handle in your own * code * * @param statusCode * the status code of the response * @param headers * the headers of the HTTP response * @param content * the body of the HTTP response from the server */ public void onSuccess(int statusCode, Header[] headers, Result<T> content) { onSuccess(statusCode, content); } /** * Fired when a request returns successfully, override to handle in your own * code * * @param statusCode * the status code of the response * @param content * the body of the HTTP response from the server */ public void onSuccess(int statusCode, Result<T> content) { onSuccess(content); } /** * Fired when a request fails to complete, override to handle in your own * code * * @param error * the underlying cause of the failure * @param content * the response body, if any */ public void onFailure(Throwable error, String content) { } // // Pre-processing of messages (executes in background threadpool thread) // protected void sendSuccessMessage(int statusCode, Header[] headers, String responseBody) { mParser.parse(responseBody); sendMessage(obtainMessage(SUCCESS_MESSAGE, new Object[] { new Integer(statusCode), headers, mParser.getResult() })); } protected void sendFailureMessage(Throwable e, String responseBody) { sendMessage(obtainMessage(FAILURE_MESSAGE, new Object[] { e, responseBody })); } protected void sendFailureMessage(Throwable e, byte[] responseBody) { sendMessage(obtainMessage(FAILURE_MESSAGE, new Object[] { e, responseBody })); } protected void sendStartMessage() { sendMessage(obtainMessage(START_MESSAGE, null)); } protected void sendFinishMessage() { sendMessage(obtainMessage(FINISH_MESSAGE, null)); } // // Pre-processing of messages (in original calling thread, typically the UI // thread) // protected void handleSuccessMessage(int statusCode, Header[] headers, Result<T> responseBody) { onSuccess(statusCode, headers, responseBody); } protected void handleFailureMessage(Throwable e, String responseBody) { onFailure(e, responseBody); } // Methods which emulate android's Handler and Message methods protected void handleMessage(Message msg) { Object[] response; switch (msg.what) { case SUCCESS_MESSAGE: response = (Object[]) msg.obj; handleSuccessMessage(((Integer) response[0]).intValue(), (Header[]) response[1], (Result<T>) response[2]); break; case FAILURE_MESSAGE: response = (Object[]) msg.obj; handleFailureMessage((Throwable) response[0], (String) response[1]); break; case START_MESSAGE: onStart(); break; case FINISH_MESSAGE: onFinish(); break; } } protected void sendMessage(Message msg) { if (handler != null) { handler.sendMessage(msg); } else { handleMessage(msg); } } protected Message obtainMessage(int responseMessage, Object response) { Message msg = null; if (handler != null) { msg = this.handler.obtainMessage(responseMessage, response); } else { msg = Message.obtain(); msg.what = responseMessage; msg.obj = response; } return msg; } // Interface to AsyncHttpRequest void sendResponseMessage(HttpResponse response) { StatusLine status = response.getStatusLine(); String responseBody = null; try { HttpEntity entity = null; HttpEntity temp = response.getEntity(); if (temp != null) { entity = new BufferedHttpEntity(temp); responseBody = EntityUtils.toString(entity, "UTF-8"); } } catch (IOException e) { sendFailureMessage(e, (String) null); } if (status.getStatusCode() >= 300) { sendFailureMessage(new HttpResponseException(status.getStatusCode(), status.getReasonPhrase()), responseBody); } else { sendSuccessMessage(status.getStatusCode(), response.getAllHeaders(), responseBody); } } }