Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.waveprotocol.wave.client.doodad.attachment; import com.google.gwt.http.client.Request; import com.google.gwt.http.client.RequestBuilder; import com.google.gwt.http.client.RequestCallback; import com.google.gwt.http.client.RequestException; import com.google.gwt.http.client.Response; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.waveprotocol.box.attachment.jso.AttachmentsResponseJsoImpl; import org.waveprotocol.box.attachment.jso.AttachmentMetadataJsoImpl; import org.waveprotocol.wave.client.debug.logger.DomLogger; import org.waveprotocol.wave.client.scheduler.Scheduler.Task; import org.waveprotocol.wave.client.scheduler.SchedulerInstance; import org.waveprotocol.wave.client.scheduler.TimerService; import org.waveprotocol.wave.common.logging.LoggerBundle; import org.waveprotocol.wave.communication.gwt.JsonMessage; import org.waveprotocol.wave.communication.json.JsonException; import org.waveprotocol.wave.media.model.Attachment; import org.waveprotocol.wave.model.util.CollectionUtils; /** * Gets attachments meta info from server. * * @author akaplanov@gmail.com (A. Kaplanov) */ public class AttachmentManagerImpl implements SimpleAttachmentManager { interface GetAttachmentsInfoCallback { public void onSuccess(List<Attachment> attachments); public void onFailure(List<Attachment> attachments, String message); } private static final String ATTACHMENTS_INFO_URL_BASE = "/attachmentsInfo"; private static final LoggerBundle LOG = new DomLogger(AttachmentManagerImpl.class.getName()); private static SimpleAttachmentManager instance; private final TimerService scheduler; private final Map<String, AttachmentImpl> attachmentsInfo = new HashMap<String, AttachmentImpl>(); private final List<String> pendingQueue = new ArrayList<String>(); private final List<Listener> listeners = new ArrayList<Listener>(); public static SimpleAttachmentManager getInstance() { if (instance != null) { return instance; } instance = new AttachmentManagerImpl(); return instance; } private Task getAttachmentsInfoTask = new Task() { @Override public void execute() { getAttachmentsInfo(new GetAttachmentsInfoCallback() { @Override public void onSuccess(List<Attachment> attachments) { for (Attachment attachment : attachments) { notifyImageUpdated(attachment); } } @Override public void onFailure(List<Attachment> attachments, String message) { LOG.error().log("Getting of attachments info failed: " + message); for (Attachment attachment : attachments) { notifyImageUpdated(attachment); } } }); } }; private AttachmentManagerImpl() { this.scheduler = SchedulerInstance.getMediumPriorityTimer(); } @Override public Attachment getAttachment(String attachmentId) { AttachmentImpl attachment = attachmentsInfo.get(attachmentId); if (attachment == null) { attachment = new AttachmentImpl(); attachmentsInfo.put(attachmentId, attachment); if (!pendingQueue.contains(attachmentId)) { pendingQueue.add(attachmentId); scheduler.schedule(getAttachmentsInfoTask); } } return attachment; } @Override public void addListener(Listener listener) { listeners.add(listener); } @Override public void removeListener(Listener listener) { listeners.remove(listener); } private void notifyImageUpdated(Attachment attachment) { for (Listener listener : listeners) { listener.onContentUpdated(attachment); listener.onThumbnailUpdated(attachment); } } private void getAttachmentsInfo(final GetAttachmentsInfoCallback callback) { LOG.trace().log("Getting attachments info"); String request = ATTACHMENTS_INFO_URL_BASE + "?attachmentIds="; for (String attacmentId : pendingQueue) { if (!request.endsWith("=")) { request += ","; } request += attacmentId; } final List<String> requestedAttachments = new ArrayList<String>(pendingQueue); pendingQueue.clear(); RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, request); requestBuilder.setCallback(new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { LOG.trace().log("Attachments info was received: ", response.getText()); if (response.getStatusCode() != Response.SC_OK) { callback.onFailure(setFailureStatus(requestedAttachments), "Got back status code " + response.getStatusCode()); } else if (!response.getHeader("Content-Type").startsWith("application/json")) { callback.onFailure(setFailureStatus(requestedAttachments), "Search service did not return json"); } else { AttachmentsResponseJsoImpl attachmentsProto; try { attachmentsProto = JsonMessage.parse(response.getText()); } catch (JsonException e) { callback.onFailure(setFailureStatus(requestedAttachments), e.getMessage()); return; } List<Attachment> attachments = initializeAttachments(attachmentsProto); callback.onSuccess(attachments); } } @Override public void onError(Request request, Throwable e) { LOG.error().log("Getting attachments info error: ", e); callback.onFailure(setFailureStatus(requestedAttachments), e.getMessage()); } }); try { requestBuilder.send(); } catch (RequestException e) { callback.onFailure(setFailureStatus(requestedAttachments), e.getMessage()); } } private List<Attachment> initializeAttachments(AttachmentsResponseJsoImpl protoAttachments) { List<Attachment> attachments = CollectionUtils.newArrayList(); for (AttachmentMetadataJsoImpl protoAttachment : protoAttachments.getAttachment()) { AttachmentImpl attachment = attachmentsInfo.get(protoAttachment.getAttachmentId()); if (attachment != null) { attachment.copyMetadata(protoAttachment); attachments.add(attachment); } } return attachments; } private List<Attachment> setFailureStatus(List<String> attachmentIds) { List<Attachment> attachments = new ArrayList<Attachment>(); for (String attachmentId : attachmentIds) { AttachmentImpl attachment = attachmentsInfo.get(attachmentId); if (attachment != null) { attachment.setStatus(Attachment.Status.FAILED_AND_NOT_RETRYABLE); attachments.add(attachment); } } return attachments; } }