com.vmware.appfactory.file.upload.ProgressReporter.java Source code

Introduction

Here is the source code for com.vmware.appfactory.file.upload.ProgressReporter.java

Source

/* ***********************************************************************
 * VMware ThinApp Factory
 * Copyright (c) 2009-2013 VMware, Inc. All Rights Reserved.
 *
 * 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.vmware.appfactory.file.upload;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This is a utility class that provides utility methods to manage upload progress of a file upload.
 * This is achieved by setting a unique Id into the init method, which in turn will be used to associate
 * is stored in HttpSession.
 *
 * This class provides methods to initialize, add, remove and fetch ProgressListener associated with the
 * CustomMultipartResolverWithProgress for tracking upload progress.
 *
 * @see ProgressListener
 * @see CustomMultipartResolverWithProgress
 * @author Keerthi Singri
 */
public class ProgressReporter {
    private static final Logger _log = LoggerFactory.getLogger(ProgressReporter.class);

    // The key whose value will be used for storing the ProgressListener in the users session.
    private static final String UPLOAD_REQUEST_ID = "TAF_uploadId";

    // An id prefix against which ProgressListener is stored.
    private static final String PROGRESS_KEY_PREFIX = "TAF_pListener_";

    /**
     * This method initializes the progress reporting by creating a new uploadId and storing it in the
     * user session for use when a file upload happens.
     *
     * @param request
     * @param uploadId
     */
    public static void initProgressListener(HttpServletRequest request, String uploadId) {
        if (StringUtils.isEmpty(uploadId)) {
            // If no key, we will not initiate any upload tracking session variable.
            _log.warn("No uploadKey passed, ignore this request.");
            return;
        }
        request.getSession().setAttribute(UPLOAD_REQUEST_ID, uploadId);
        _log.debug("added uploadKey: {} into session", uploadId);
    }

    /**
     * This method adds the ProgressListener to the session based on the keyPrefix as available.
     * This method can be invoked only by CustomMultipartResolverWithProgress and hence the limited visibility.
     *
     * @param request
     * @param progressListener
     */
    static void addProgressListener(HttpServletRequest request, ProgressListener progressListener) {
        String uploadId = (String) request.getSession().getAttribute(UPLOAD_REQUEST_ID);
        if (StringUtils.isEmpty(uploadId)) {
            // If no key, we cant store the progressListener in session and hence no upload progress.
            _log.warn("No uploadId available, hence we do not track the ProgressListener");
            return;
        }

        String sessionKey = createSessionKey(uploadId);

        // Add the progressListener onto the session for progress reporting.
        request.getSession().setAttribute(sessionKey, progressListener);

        // Remove this session variable(if exists), as its not needed anymore.
        request.getSession().removeAttribute(UPLOAD_REQUEST_ID);
    }

    /**
     * Get the progress of the upload in the form of a clone copy of ProgressListenerImpl.
     *
     * @param request - HttpServletRequest
     * @param uploadId - a key representing the progress copy in session.
     * @return implementation of ProgressListener
     */
    public static ProgressListener getProgressListener(HttpServletRequest request, String uploadId) {
        if (uploadId != null) {
            ProgressListener pListener = (ProgressListener) request.getSession()
                    .getAttribute(createSessionKey(uploadId));

            // Return a clone copy of the listener.
            if (pListener instanceof ProgressListenerImpl) {
                return ((ProgressListenerImpl) pListener).clone();
            }
        }

        /* The upload process may have already finished and AppApiController.uploadAndCreate()
         * may have removed ProgressListener instance from session already. Hence return null.
         */
        return null;
    }

    /**
     * Removes the ProgressListener from the HttpSession associated with the input parameter uploadId.
     *
     * @param request
     * @param uploadId
     */
    public static void removeProgressListener(HttpServletRequest request, String uploadId) {
        if (uploadId != null) {
            String sessionKey = createSessionKey(uploadId);
            request.getSession().removeAttribute(sessionKey);
            _log.trace("Remove session attr with key: " + sessionKey);
        }
    }

    /**
     * Concatenates the unique key with prefix to make the key used to store the ProgressListener.
     *
     * @param uploadId
     * @return
     */
    private static String createSessionKey(String uploadId) {
        return PROGRESS_KEY_PREFIX + uploadId;
    }
}