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.yunmall.ymsdk.net.http; import android.text.TextUtils; import com.yunmall.ymsdk.net.http.model.CacheData; import com.yunmall.ymsdk.utility.YmLog; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.net.MalformedURLException; import java.net.UnknownHostException; import org.apache.http.HttpResponse; import org.apache.http.client.HttpRequestRetryHandler; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.impl.client.AbstractHttpClient; import org.apache.http.protocol.HttpContext; /** * Internal class, representing the HttpRequest, done in asynchronous manner */ public class AsyncHttpRequest implements Runnable { public static final String TAG = "AsyncHttpRequest"; private final AbstractHttpClient client; private final HttpContext context; private final HttpUriRequest request; private final ResponseHandlerInterface responseHandler; private int executionCount; private boolean isCancelled = false; private boolean cancelIsNotified = false; private boolean isFinished = false; public AsyncHttpRequest(AbstractHttpClient client, HttpContext context, HttpUriRequest request, ResponseHandlerInterface responseHandler) { this.client = client; this.context = context; this.request = request; this.responseHandler = responseHandler; } @Override public void run() { if (isCancelled() || responseHandler == null) { return; } if (responseHandler != null) { responseHandler.sendStartMessage(); } if (isCancelled()) { return; } CacheData cacheData = loadCache(responseHandler); if (cacheData != null) { if (!isCancelled() && responseHandler != null) { responseHandler.sendCacheMessage(cacheData.cacheData, cacheData.time); } else { YmLog.e(TAG, "makeRequestWithRetries returned error, but handler is null"); } } try { makeRequestWithRetries(); } catch (IOException e) { if (!isCancelled() && responseHandler != null) { responseHandler.sendFailureMessage(0, null, null, e); } else { YmLog.e(TAG, "makeRequestWithRetries returned error, but handler is null", e); } } if (isCancelled()) { return; } if (responseHandler != null) { responseHandler.sendFinishMessage(); } isFinished = true; } private void makeRequest() throws IOException { if (isCancelled()) { return; } // Fixes #115 if (request.getURI().getScheme() == null) { // subclass of IOException so processed in the caller throw new MalformedURLException("No valid URI scheme was provided"); } HttpResponse response = client.execute(request, context); if (!isCancelled() && responseHandler != null) { responseHandler.sendResponseMessage(response); } } private void makeRequestWithRetries() throws IOException { boolean retry = true; IOException cause = null; HttpRequestRetryHandler retryHandler = client.getHttpRequestRetryHandler(); try { while (retry) { try { makeRequest(); return; } catch (UnknownHostException e) { // switching between WI-FI and mobile data networks can cause a retry which then results in an UnknownHostException // while the WI-FI is initialising. The retry logic will be invoked here, if this is NOT the first retry // (to assist in genuine cases of unknown host) which seems better than outright failure cause = new IOException("UnknownHostException exception: " + e.getMessage()); retry = (executionCount > 0) && retryHandler.retryRequest(cause, ++executionCount, context); } catch (NullPointerException e) { // there's a bug in HttpClient 4.0.x that on some occasions causes // DefaultRequestExecutor to throw an NPE, see // http://code.google.com/p/android/issues/detail?id=5255 cause = new IOException("NPE in HttpClient: " + e.getMessage()); retry = retryHandler.retryRequest(cause, ++executionCount, context); } catch (IOException e) { if (isCancelled()) { // Eating exception, as the request was cancelled return; } cause = e; retry = retryHandler.retryRequest(cause, ++executionCount, context); } if (retry && (responseHandler != null)) { responseHandler.sendRetryMessage(executionCount); } } } catch (Exception e) { // catch anything else to ensure failure message is propagated YmLog.d(TAG, "Unhandled exception origin cause", e); cause = new IOException("Unhandled exception: " + e.getMessage()); } // cleaned up to throw IOException throw (cause); } public boolean isCancelled() { if (isCancelled) { sendCancelNotification(); } return isCancelled; } private synchronized void sendCancelNotification() { if (!isFinished && isCancelled && !cancelIsNotified) { cancelIsNotified = true; if (responseHandler != null) responseHandler.sendCancelMessage(); } } public boolean isDone() { return isCancelled() || isFinished; } public boolean cancel(boolean mayInterruptIfRunning) { isCancelled = true; request.abort(); return isCancelled(); } private CacheData loadCache(ResponseHandlerInterface responseHandlerInterface) { String cacheFileName = responseHandlerInterface.getCacheFileName(); if (TextUtils.isEmpty(cacheFileName)) { return null; } CacheData cacheData = new CacheData(); File file = new File(cacheFileName); cacheData.time = file.lastModified(); if (!file.exists()) { return null; } long fileSize = file.length(); if (fileSize == 0) { clearCache(cacheFileName); return null; } long time = System.currentTimeMillis() - cacheData.time; if (time > AsyncHttpClient.DEFAULT_CACHE_EXPIRATION_TIME) { clearCache(cacheFileName); return null; } FileInputStream fis = null; try { fis = new FileInputStream(file); byte[] fileData = new byte[(int) fileSize]; if (fis.read(fileData) != fileSize) { clearCache(cacheFileName); return null; } if (fileData.length <= 0) { clearCache(cacheFileName); return null; } cacheData.cacheData = fileData; return cacheData; } catch (OutOfMemoryError e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); clearCache(cacheFileName); } finally { try { if (fis != null) { fis.close(); fis = null; } } catch (IOException e) { e.printStackTrace(); } } return null; } private boolean clearCache(String filePath) { File file = new File(filePath); return file.exists() && file.delete(); } }