Java tutorial
/* * Copyright (C) 2009 The Android Open Source Project * * 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 org.linuxguy.HPCCMonWidget; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.params.ClientPNames; import org.apache.http.client.params.CookiePolicy; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import org.linuxguy.HPCCMonWidget.R; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.content.pm.PackageManager.NameNotFoundException; import android.net.Uri; import android.util.Log; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; /** * Helper methods. */ public class Helper { private static final String TAG = "Helper"; /** * Regular expression that splits "Word of the day" entry into word * name, word type, and the first description bullet point. */ public static final String HPCC_REGEX = "(\\d+) Current.+\\n.+(\\d+ Finished)"; /** * Partial URL to use when requesting an HPCC status. */ private static String HPCCSTATS_PAGE = ""; private static String HPCCSTATS_USER = ""; /** * {@link StatusLine} HTTP status code when no server error has occurred. */ private static final int HTTP_STATUS_OK = 200; /** * Shared buffer used by {@link #getUrlContent(String)} when reading results * from an API request. */ private static byte[] sBuffer = new byte[512]; /** * User-agent string to use when making requests. Should be filled using * {@link #prepareUserAgent(Context)} before making any other calls. */ private static String sUserAgent = "HPCCMon"; /** * Thrown when there were problems contacting the remote API server, either * because of a network error, or the server returned a bad status code. */ public static class ApiException extends Exception { public ApiException(String detailMessage, Throwable throwable) { super(detailMessage, throwable); } public ApiException(String detailMessage) { super(detailMessage); } } /** * Thrown when there were problems parsing the response to an API call, * either because the response was empty, or it was malformed. */ public static class ParseException extends Exception { public ParseException(String detailMessage, Throwable throwable) { super(detailMessage, throwable); } } public static void prepareHPCCData(Context context) { if (HPCCSTATS_USER == "" || getHPCCPage() == "") { SharedPreferences prefs = context.getSharedPreferences("org.linuxguy.HPCCMonWidget", 0); HPCCSTATS_USER = prefs.getString("hpccmonwidget_user", ""); setHPCCPage(prefs.getString("hpccmonwidget_url", "")); Log.i("Status", "prepareHPCCData()"); } } /** * Prepare the internal User-Agent string for use. This requires a * {@link Context} to pull the package name and version number for this * application. */ public static void prepareUserAgent(Context context) { try { // Read package name and version number from manifest PackageManager manager = context.getPackageManager(); PackageInfo info = manager.getPackageInfo(context.getPackageName(), 0); sUserAgent = "HPCCMonWidget/Android"; } catch (NameNotFoundException e) { Log.e(TAG, "Couldn't find package information in PackageManager", e); } } /** * Read and return the content for HPCC runs owned by a specific user. * Because this call blocks until results are available, it should not be * run from a UI thread. * * @return Exact content of page. * @throws ApiException If any connection or server error occurs. * @throws ParseException If there are problems parsing the response. */ public static String getPageContent() throws ApiException, ParseException { // Query the API for content String URI = getHPCCPage() + "?username=" + getHPCCUser(); Log.i("HPCCMonWidget", "Polling " + URI); return getUrlContent(URI); } /** * Pull the raw text content of the given URL. This call blocks until the * operation has completed, and is synchronized because it uses a shared * buffer {@link #sBuffer}. * * @param url The exact URL to request. * @return The raw content returned by the server. * @throws ApiException If any connection or server error occurs. */ protected static synchronized String getUrlContent(String url) throws ApiException { if (sUserAgent == null) { throw new ApiException("User-Agent string must be prepared"); } // Create client and set our specific user-agent string HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(url); request.setHeader("User-Agent", sUserAgent); try { HttpResponse response = client.execute(request); // Check if server response is valid StatusLine status = response.getStatusLine(); if (status.getStatusCode() != HTTP_STATUS_OK) { throw new ApiException("Invalid response from server: " + status.toString()); } // Pull content stream from response HttpEntity entity = response.getEntity(); InputStream inputStream = entity.getContent(); ByteArrayOutputStream content = new ByteArrayOutputStream(); // Read response into a buffered stream int readBytes = 0; while ((readBytes = inputStream.read(sBuffer)) != -1) { content.write(sBuffer, 0, readBytes); } // Return result from buffered stream return new String(content.toByteArray()); } catch (IOException e) { throw new ApiException("Problem communicating with API", e); } } public static void setHPCCUser(String hPCCSTATS_USER) { HPCCSTATS_USER = hPCCSTATS_USER; } public static String getHPCCUser() { return HPCCSTATS_USER; } public static void setHPCCPage(String hPCCSTATS_PAGE) { HPCCSTATS_PAGE = hPCCSTATS_PAGE; } public static String getHPCCPage() { return HPCCSTATS_PAGE; } }