Java tutorial
/* ownCloud Android Library is available under MIT license * Copyright (C) 2014 ownCloud Inc. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. * */ package com.owncloud.android.lib.resources.files; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.methods.HeadMethod; import android.content.Context; import android.net.ConnectivityManager; import com.owncloud.android.lib.common.OwnCloudClient; import com.owncloud.android.lib.common.network.WebdavUtils; import com.owncloud.android.lib.common.operations.RemoteOperation; import com.owncloud.android.lib.common.operations.RemoteOperationResult; import com.owncloud.android.lib.common.utils.Log_OC; /** * Operation to check the existence or absence of a path in a remote server. * * @author David A. Velasco */ @SuppressWarnings("ALL") public class ExistenceCheckRemoteOperation extends RemoteOperation { /** Maximum time to wait for a response from the server in MILLISECONDs. */ public static final int TIMEOUT = 10000; private static final String TAG = ExistenceCheckRemoteOperation.class.getSimpleName(); private String mPath; private Context mContext; private boolean mSuccessIfAbsent; /** * Full constructor. Success of the operation will depend upon the value of successIfAbsent. * * @param remotePath Path to append to the URL owned by the client instance. * @param context Android application context. * @param successIfAbsent When 'true', the operation finishes in success if the path does NOT exist in the remote server (HTTP 404). */ public ExistenceCheckRemoteOperation(String remotePath, Context context, boolean successIfAbsent) { mPath = (remotePath != null) ? remotePath : ""; mContext = context; mSuccessIfAbsent = successIfAbsent; } @Override protected RemoteOperationResult run(OwnCloudClient client) { if (!isOnline()) { return new RemoteOperationResult(RemoteOperationResult.ResultCode.NO_NETWORK_CONNECTION); } RemoteOperationResult result = null; HeadMethod head = null; try { head = new HeadMethod(client.getWebdavUri() + WebdavUtils.encodePath(mPath)); int status = client.executeMethod(head, TIMEOUT, TIMEOUT); client.exhaustResponse(head.getResponseBodyAsStream()); boolean success = (status == HttpStatus.SC_OK && !mSuccessIfAbsent) || (status == HttpStatus.SC_NOT_FOUND && mSuccessIfAbsent); result = new RemoteOperationResult(success, status, head.getResponseHeaders()); Log_OC.d(TAG, "Existence check for " + client.getWebdavUri() + WebdavUtils.encodePath(mPath) + " targeting for " + (mSuccessIfAbsent ? " absence " : " existence ") + "finished with HTTP status " + status + (!success ? "(FAIL)" : "")); } catch (Exception e) { result = new RemoteOperationResult(e); Log_OC.e(TAG, "Existence check for " + client.getWebdavUri() + WebdavUtils.encodePath(mPath) + " targeting for " + (mSuccessIfAbsent ? " absence " : " existence ") + ": " + result.getLogMessage(), result.getException()); } finally { if (head != null) head.releaseConnection(); } return result; } private boolean isOnline() { ConnectivityManager cm = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE); return cm != null && cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnectedOrConnecting(); } }