Java tutorial
package org.activityinfo.ui.client.component.form.field.image; /* * #%L * ActivityInfo Server * %% * Copyright (C) 2009 - 2013 UNICEF * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program. If not, see * <http://www.gnu.org/licenses/gpl-3.0.html>. * #L% */ import com.google.common.base.Strings; import com.google.common.collect.Lists; import com.google.gwt.core.client.GWT; import com.google.gwt.dom.client.ImageElement; import com.google.gwt.event.dom.client.ChangeEvent; import com.google.gwt.event.dom.client.ChangeHandler; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.shared.HandlerRegistration; 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.http.client.URL; import com.google.gwt.uibinder.client.UiBinder; import com.google.gwt.uibinder.client.UiField; 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.FileUpload; import com.google.gwt.user.client.ui.FormPanel; import com.google.gwt.user.client.ui.HTMLPanel; import com.google.gwt.user.client.ui.Hidden; import com.google.gwt.user.client.ui.Image; import com.google.gwt.user.client.ui.VerticalPanel; import com.google.gwt.user.client.ui.Widget; import org.activityinfo.core.shared.util.MimeTypeUtil; import org.activityinfo.legacy.shared.Log; import org.activityinfo.model.resource.Resource; import org.activityinfo.model.resource.ResourceId; import org.activityinfo.model.resource.Resources; import org.activityinfo.model.type.image.ImageRowValue; import org.activityinfo.service.blob.UploadCredentials; import java.util.List; import java.util.Map; /** * @author yuriyz on 8/12/14. */ public class ImageUploadRow extends Composite { private static final int THUMBNAIL_SIZE = 24; interface OurUiBinder extends UiBinder<FormPanel, ImageUploadRow> { } private static OurUiBinder ourUiBinder = GWT.create(OurUiBinder.class); private final ImageRowValue value; private final String fieldId; private final String resourceId; private boolean readOnly; private HandlerRegistration oldHandler; @UiField FileUpload fileUpload; @UiField HTMLPanel imageContainer; @UiField ImageElement loadingImage; @UiField Image thumbnail; @UiField Button downloadButton; @UiField Button removeButton; @UiField VerticalPanel formFieldsContainer; @UiField Button addButton; @UiField FormPanel formPanel; public ImageUploadRow(ImageRowValue value, String fieldId, String resourceId) { initWidget(ourUiBinder.createAndBindUi(this)); this.value = value; this.fieldId = fieldId; this.resourceId = resourceId; fileUpload.addChangeHandler(new ChangeHandler() { @Override public void onChange(ChangeEvent event) { requestUploadUrl(); } }); downloadButton.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { download(); } }); if (value.getBlobId() != null) { imageContainer.setVisible(false); downloadButton.setVisible(true); thumbnail.setVisible(true); thumbnail.setUrl(buildThumbnailUrl()); } } public boolean isReadOnly() { return readOnly; } public void setReadOnly(boolean readOnly) { this.readOnly = readOnly; fileUpload.setEnabled(!readOnly); downloadButton.setEnabled(!readOnly); removeButton.setEnabled(!readOnly); addButton.setEnabled(!readOnly); } private String createUploadUrl() { String blobId = ResourceId.generateId().asString(); String fileName = fileName(); String mimeType = MimeTypeUtil.mimeTypeFromFileExtension(fileExtension(fileName)); value.setMimeType(mimeType); value.setFilename(fileName); value.setBlobId(blobId); return "/service/blob/credentials/" + blobId; } public static String fileExtension(String filename) { int i = filename.lastIndexOf("."); if (i != -1) { return filename.substring(i + 1); } return filename; } private String fileName() { final String filename = fileUpload.getFilename(); if (Strings.isNullOrEmpty(filename)) { return "unknown"; } int i = filename.lastIndexOf("/"); if (i == -1) { i = filename.lastIndexOf("\\"); } if (i != -1 && (i + 1) < filename.length()) { return filename.substring(i + 1); } return filename; } private void requestUploadUrl() { try { RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.POST, URL.encode(createUploadUrl())); requestBuilder.sendRequest(null, new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { String json = response.getText(); Resource resource = Resources.fromJson(json); UploadCredentials uploadCredentials = UploadCredentials.fromRecord(resource); // Remove the old hidden fields before adding the new ones List<Hidden> hidden = Lists.newArrayListWithCapacity(formFieldsContainer.getWidgetCount()); for (int i = 0; i < formFieldsContainer.getWidgetCount(); i++) { Widget widget = formFieldsContainer.getWidget(i); if (widget instanceof Hidden) { hidden.add((Hidden) widget); } } // We can't just iterate once using the getWidget() method because removing a widget changes indexes for (Hidden old : hidden) { formFieldsContainer.remove(old); } Map<String, String> formFields = uploadCredentials.getFormFields(); for (Map.Entry<String, String> field : formFields.entrySet()) { formFieldsContainer.add(new Hidden(field.getKey(), field.getValue())); } formPanel.setAction(uploadCredentials.getUrl()); formPanel.setMethod(uploadCredentials.getMethod()); upload(); } @Override public void onError(Request request, Throwable exception) { Log.error("Failed to send request", exception); } }); } catch (RequestException e) { Log.error("Failed to send request", e); } } private void upload() { imageContainer.setVisible(true); downloadButton.setVisible(false); if (oldHandler != null) oldHandler.removeHandler(); oldHandler = formPanel.addSubmitCompleteHandler(new FormPanel.SubmitCompleteHandler() { @Override public void onSubmitComplete(FormPanel.SubmitCompleteEvent event) { String responseString = event.getResults(); // what about fail results? imageContainer.setVisible(false); downloadButton.setVisible(true); thumbnail.setVisible(true); thumbnail.setUrl(buildThumbnailUrl()); } }); formPanel.submit(); } private void download() { Window.open(buildImageUrl(), "_blank", null); } @Override public Widget asWidget() { return this; } public ImageRowValue getValue() { return value; } private StringBuilder buildBaseUrl() { StringBuilder stringBuilder = new StringBuilder("/service/blob/"); stringBuilder.append(resourceId); stringBuilder.append("/"); stringBuilder.append(fieldId); stringBuilder.append("/"); stringBuilder.append(value.getBlobId()); return stringBuilder; } private String buildThumbnailUrl() { StringBuilder stringBuilder = buildBaseUrl(); stringBuilder.append("/thumbnail?width="); stringBuilder.append(THUMBNAIL_SIZE); stringBuilder.append("&height="); stringBuilder.append(THUMBNAIL_SIZE); return stringBuilder.toString(); } private String buildImageUrl() { StringBuilder stringBuilder = buildBaseUrl(); stringBuilder.append("/image"); return stringBuilder.toString(); } }