Java tutorial
/** * The contents of this file are subject to the license and copyright * detailed in the LICENSE file at the root of the source * tree and available online at * * https://github.com/keeps/roda */ package org.roda.wui.client.browse; import org.apache.commons.httpclient.HttpStatus; import org.roda.core.data.v2.index.IsIndexed; import org.roda.core.data.v2.ip.IndexedDIP; import org.roda.core.data.v2.ip.metadata.FileFormat; import org.roda.wui.client.common.utils.JavascriptUtils; import org.roda.wui.client.common.utils.StringUtils; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.JavaScriptObject; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.logical.shared.AttachEvent; import com.google.gwt.event.logical.shared.AttachEvent.Handler; 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 com.google.gwt.media.client.Audio; import com.google.gwt.media.client.Video; import com.google.gwt.safehtml.shared.SafeHtmlBuilder; import com.google.gwt.safehtml.shared.SafeHtmlUtils; import com.google.gwt.safehtml.shared.SafeUri; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.Frame; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.SimplePanel; import com.google.gwt.user.client.ui.Widget; import config.i18n.client.ClientMessages; public class BitstreamPreview<T extends IsIndexed> extends Composite { private static final String VIEWER_TYPE_VIDEO = "video"; private static final String VIEWER_TYPE_AUDIO = "audio"; private static final String VIEWER_TYPE_TEXT = "text"; private static final String VIEWER_TYPE_PDF = "pdf"; private static final String VIEWER_TYPE_IMAGE = "image"; private static final ClientMessages messages = GWT.create(ClientMessages.class); // interface private final FlowPanel panel; // system properties private final Viewers viewers; // bitstream properties private final SafeUri bitstreamDownloadUri; private final FileFormat format; private final String filename; private final long size; private final boolean isDirectory; // other private final Command onPreviewFailure; private final T object; public BitstreamPreview(Viewers viewers, SafeUri bitstreamDownloadUri, FileFormat format, String filename, long size, boolean isDirectory, T object) { this(viewers, bitstreamDownloadUri, format, filename, size, isDirectory, new Command() { @Override public void execute() { // do nothing } }, object); } public BitstreamPreview(Viewers viewers, SafeUri bitstreamDownloadUri, FileFormat format, String filename, long size, boolean isDirectory, Command onPreviewFailure, T object) { super(); this.object = object; this.panel = new FlowPanel(); this.viewers = viewers; this.bitstreamDownloadUri = bitstreamDownloadUri; this.format = format; this.filename = filename; this.size = size; this.isDirectory = isDirectory; this.onPreviewFailure = onPreviewFailure; initWidget(panel); setStyleName("bitstreamPreview"); if (isDirectory) { addStyleDependentName("directory"); } init(); } public SafeUri getBitstreamDownloadUri() { return bitstreamDownloadUri; } public FileFormat getFormat() { return format; } public String getFilename() { return filename; } public long getSize() { return size; } public boolean isDirectory() { return isDirectory; } private void init() { if (!isDirectory) { String type = viewerType(); if (type != null) { if (type.equals(VIEWER_TYPE_IMAGE)) { imagePreview(); } else if (type.equals(VIEWER_TYPE_PDF)) { pdfPreview(); } else if (type.equals(VIEWER_TYPE_TEXT)) { textPreview(); } else if (type.equals(VIEWER_TYPE_AUDIO)) { audioPreview(); } else if (type.equals(VIEWER_TYPE_VIDEO)) { videoPreview(); } else { notSupportedPreview(); } } else if (object instanceof IndexedDIP) { IndexedDIP dip = (IndexedDIP) object; dipUrlPreview(dip); } else { notSupportedPreview(); } } else { panel.add(directoryPreview()); } } private String viewerType() { String type = null; if (format != null) { if (format.getPronom() != null) { type = viewers.getPronoms().get(format.getPronom()); } if (format.getMimeType() != null && type == null) { type = viewers.getMimetypes().get(format.getMimeType()); } } if (type == null && filename.lastIndexOf('.') != -1) { String extension = getFileNameExtension(); type = viewers.getExtensions().get(extension); } return type; } private String getFileNameExtension() { return filename.substring(filename.lastIndexOf('.')).toLowerCase(); } private void imagePreview() { final SimplePanel imageContainer = new SimplePanel(); panel.add(imageContainer); imageContainer.setStyleName("viewRepresentationImageFilePreview"); imageContainer.addAttachHandler(new Handler() { private JavaScriptObject imageViewer = null; @Override public void onAttachOrDetach(AttachEvent event) { if (event.isAttached()) { // load image imageViewer = JavascriptUtils.runImageViewerOn(imageContainer.getElement(), bitstreamDownloadUri.asString()); } else { // destroy if (imageViewer != null) { JavascriptUtils.stopImageViewer(imageViewer); } } } }); } private void pdfPreview() { String viewerHtml = GWT.getHostPageBaseURL() + "pdf/viewer.html?file=" + encode(GWT.getHostPageBaseURL() + bitstreamDownloadUri.asString()); Frame frame = new Frame(viewerHtml); panel.add(frame); frame.setStyleName("viewRepresentationPDFFilePreview"); } private void textPreview() { if (StringUtils.isBlank(viewers.getTextLimit()) || size <= Long.parseLong(viewers.getTextLimit())) { RequestBuilder request = new RequestBuilder(RequestBuilder.GET, bitstreamDownloadUri.asString()); try { request.sendRequest(null, new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { if (response.getStatusCode() == HttpStatus.SC_OK) { HTML html = new HTML( "<pre><code>" + SafeHtmlUtils.htmlEscape(response.getText()) + "</code></pre>"); FlowPanel frame = new FlowPanel(); frame.add(html); panel.add(frame); frame.setStyleName("viewRepresentationTextFilePreview"); JavascriptUtils.runHighlighter(html.getElement()); } else { errorPreview(); } } @Override public void onError(Request request, Throwable exception) { errorPreview(); } }); } catch (RequestException e) { errorPreview(); } } else { errorPreview(messages.viewRepresentationTooLargeErrorPreview()); } } private void audioPreview() { Audio audioPlayer = Audio.createIfSupported(); if (audioPlayer != null) { HTML html = new HTML(); SafeHtmlBuilder b = new SafeHtmlBuilder(); b.append(SafeHtmlUtils.fromSafeConstant("<i class='fa fa-headphones fa-5'></i>")); html.setHTML(b.toSafeHtml()); // TODO check if audio source type needs to be transformed // TODO check if audio player supports provided file format audioPlayer.addSource(bitstreamDownloadUri.asString(), getAudioSourceType()); audioPlayer.setControls(true); panel.add(html); panel.add(audioPlayer); audioPlayer.addStyleName("viewRepresentationAudioFilePreview"); html.addStyleName("viewRepresentationAudioFilePreviewHTML"); } else { notSupportedPreview(); } } private void videoPreview() { Video videoPlayer = Video.createIfSupported(); if (videoPlayer != null) { videoPlayer.addSource(bitstreamDownloadUri.asString(), getVideoSourceType()); videoPlayer.setControls(true); panel.add(videoPlayer); videoPlayer.addStyleName("viewRepresentationAudioFilePreview"); } else { notSupportedPreview(); } } private String getVideoSourceType() { String ret; if (format != null && StringUtils.isNotBlank(format.getMimeType())) { String mimetype = format.getMimeType(); if ("application/mp4".equals(mimetype)) { ret = "video/mp4"; } else if ("application/ogg".equals(mimetype)) { ret = "video/ogg"; } else { ret = mimetype; } } else { String extension = getFileNameExtension(); if (".ogg".equals(extension)) { ret = "video/ogg"; } else { ret = "video/mp4"; } } // TODO video player might not support provided file format return ret; } private String getAudioSourceType() { String ret; if (format != null && StringUtils.isNotBlank(format.getMimeType())) { String mimetype = format.getMimeType(); ret = mimetype; } else { String extension = getFileNameExtension(); if (".ogg".equals(extension)) { ret = "audio/ogg"; } else { ret = "audio/mpeg"; } } // TODO audio player might not support provided file format return ret; } private void dipUrlPreview(IndexedDIP dip) { Frame frame = new Frame(dip.getOpenExternalURL()); frame.setStyleName("viewDIPPreview"); frame.setTitle(dip.getTitle()); panel.add(frame); } private String encode(String string) { return string.replace("?", "%3F").replace("=", "%3D"); } private void errorPreview() { errorPreview(messages.viewRepresentationErrorPreview()); } private void errorPreview(String errorPreview) { HTML html = new HTML(); SafeHtmlBuilder b = new SafeHtmlBuilder(); b.append(SafeHtmlUtils.fromSafeConstant("<i class='fa fa-download fa-5'></i>")); b.append(SafeHtmlUtils.fromSafeConstant("<h4 class='errormessage'>")); b.append(SafeHtmlUtils.fromString(errorPreview)); b.append(SafeHtmlUtils.fromSafeConstant("</h4>")); Button downloadButton = new Button(messages.viewRepresentationDownloadFileButton()); downloadButton.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { downloadFile(); } }); html.setHTML(b.toSafeHtml()); panel.add(html); panel.add(downloadButton); html.setStyleName("viewRepresentationErrorPreview"); downloadButton.setStyleName("btn btn-donwload viewRepresentationNotSupportedDownloadButton"); onPreviewFailure.execute(); } private void notSupportedPreview() { HTML html = new HTML(); SafeHtmlBuilder b = new SafeHtmlBuilder(); b.append(SafeHtmlUtils.fromSafeConstant("<i class='fa fa-picture-o fa-5'></i>")); b.append(SafeHtmlUtils.fromSafeConstant("<h4 class='errormessage'>")); b.append(SafeHtmlUtils.fromString(messages.viewRepresentationNotSupportedPreview())); b.append(SafeHtmlUtils.fromSafeConstant("</h4>")); Button downloadButton = new Button(messages.viewRepresentationDownloadFileButton()); downloadButton.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { downloadFile(); } }); html.setHTML(b.toSafeHtml()); panel.add(html); panel.add(downloadButton); html.setStyleName("viewRepresentationNotSupportedPreview"); downloadButton.setStyleName("btn btn-download viewRepresentationNotSupportedDownloadButton"); onPreviewFailure.execute(); } protected Widget directoryPreview() { HTML html = new HTML(); SafeHtmlBuilder b = new SafeHtmlBuilder(); b.append(SafeHtmlUtils.fromSafeConstant("<i class='fa fa-folder-open fa-5'></i>")); b.append(SafeHtmlUtils.fromSafeConstant("<h4 class='emptymessage'>")); b.append(SafeHtmlUtils.fromString(filename + " /")); b.append(SafeHtmlUtils.fromSafeConstant("</h4>")); html.setHTML(b.toSafeHtml()); html.setStyleName("viewRepresentationEmptyPreview"); return html; } private void downloadFile() { if (bitstreamDownloadUri != null) { Window.Location.assign(bitstreamDownloadUri.asString()); } } public T getObject() { return object; } }