com.siderakis.upload4gwt.client.UploadFormPanel.java Source code

Introduction

Here is the source code for com.siderakis.upload4gwt.client.UploadFormPanel.java

Source

/*
 * Copyright 2010 Nick Siderakis.
 * 
 * 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.siderakis.upload4gwt.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.FormPanel;

/**
 * 
 * Adds functionality to support a StatusDisplay (progress bar) to the GWT
 * FormPanel. Uses an uploadId to support multiple uploads.
 * 
 * */
public class UploadFormPanel extends FormPanel {
    private String uploadId = null;
    private HasProgress statusDisplay = null;
    final ProgressSyncer progressSyncer = ProgressSyncer.getInstance();

    private String actionBase;

    public UploadFormPanel() {
        this(false);
    }

    public UploadFormPanel(final Boolean prefetchId) {
        super();

        if (prefetchId) {
            progressSyncer.getNextId(new AsyncCallback<String>() {

                @Override
                public void onFailure(final Throwable caught) {
                }

                @Override
                public void onSuccess(final String result) {
                    uploadId = result;
                    setAction(actionBase);
                }
            });
        }
        // Because we're going to add a FileUpload widget, we'll need to set the
        // form to use the POST method, and multipart MIME encoding.
        setEncoding(FormPanel.ENCODING_MULTIPART);
        setMethod(FormPanel.METHOD_POST);

        addSubmitHandler(new FormPanel.SubmitHandler() {
            @Override
            public void onSubmit(final SubmitEvent event) {
                // This event is fired just before the form is submitted. We can
                // take this opportunity to perform validation.
                if (uploadId == null) {
                    event.cancel();
                    GWT.log("UploadId is null");
                    // try to get an id
                    progressSyncer.getNextId(new AsyncCallback<String>() {

                        @Override
                        public void onFailure(final Throwable caught) {
                        }

                        @Override
                        public void onSuccess(final String result) {
                            // after id is received set it on form
                            uploadId = result;
                            setAction(actionBase);
                            // then resubmit
                            submit();
                        }
                    });
                } else {
                    progressSyncer.addStatusDisplay(uploadId, statusDisplay);
                    progressSyncer.start(uploadId);
                }
            }
        });
        addSubmitCompleteHandler(new FormPanel.SubmitCompleteHandler() {
            @Override
            public void onSubmitComplete(final SubmitCompleteEvent event) {
                // When the form submission is successfully completed, this
                // event is fired. Assuming the service returned a response of
                // type
                // text/html, we can get the result text here (see the FormPanel
                // documentation for further explanation).
                // Window.alert(event.getResults());

                // progressSyncer.stop();
            }
        });

    }

    @Override
    public void setAction(final String url) {
        actionBase = url;
        super.setAction(url + (url.contains("?") ? "&" : "?") + "uploadId=" + uploadId);
    }

    public void setStatusDisplay(final HasProgress statusDisplay) {
        this.statusDisplay = statusDisplay;
        progressSyncer.addStatusDisplay(uploadId, statusDisplay);

    }

}