I have just started working with GWT. I was wondering how I can dynamically move widgets on fly (at web page on client browser) for example to move a row of table up and down, or upload a excel file and display its content right away....something like a dashboard I am talking about. Are there any comprehensive tutorial to refer.
Have a look at the gwt-dnd lib:
http://code.google.com/p/gwt-dnd/
GWT is made for doing the kind of things you are describing. To move widgets you can either set their position or dynamically modify their css. To move rows around in a table look at the api of whatever table class you are using. To upload an excel file do a google search for 'gwt upload' and there will be some instructions - but to display the file you will need to convert it (probably to xml). Converting the file on the server will depend on which server you are using - I also have seen a 3rd party widget that will do that for you.
If youre looking for transition effects or animations , than check out gwtquery. Its really similar to jquery and has pretty simple good examples to start with.
Related
We are trying to develop a website for tracking the progress of pipeline and assets. I want to link progress data entered from forms developed in Java to GIS. We will be capturing all the lat and longs of pipeline stretch and lat and log of progress of work.
I need help in developing shapefile dynamically based on the progress and also to view that shape file in my webpage
The javascript API does have functionality for uploading shapefiles form your desktop into the browser, but you will need another tool to create those shapefiles based on the progress.
For uploading the shapefiles, see the example here: https://developers.arcgis.com/javascript/3/jssamples/portal_addshapefile.html
There may be more examples available at https://developers.arcgis.com/javascript/3/.
For creating the shapefiles dynamically, you could use ArcMap or ArcPro if you have those, or one of many python libraries to help write shapefiles. There may even be some Java libraries to help with this as well but I only work on the front end so I cannot help you there.
For something simple in context, the complexity of what kind of workflow to best suite your needs can range depending on these questions (and probably others I'm not thinking of):
Do you absolutely need to create a shapefile for this? Why can't you just push the form to a spatial database (e.g. PostGIS) and then return the XYs of the points or the string of XYs for line features, etc.?
Where is the source of the data & what is the format? Is it a PDF, text on an HTML page, a .csv file downloadable from a page, etc.? You may need to implement scraping (from a site) or download and update, or your data could be live streaming - these are all different workflows and you need to establish these boundaries before setting up your workflow.
If your end game are points, all you need is XYs in a table format to display in GIS software. If they are lines or polygons, it'd be a little different. Again - what output type are they and what are you trying to do with it (e.g. import into QGIS)?
Without these answers, it doesn't make sense for anyone to suggest something to you that could be totally impossible for you to execute. Please answer these and think through your workflow from beginning to end and/or visa versa.
Cheers,
Shawn
I want to represent a business process that I will have from an XML file and represent it in a JPanel, and I need also to visualize its evolution in time by changing colors (for example).
Do you know from where I should start, or if jBPMN can be connected to java and represented in my interface.
Any help will be appreciated.
The jBPM web designer can generate a PNG or SVG from an XML file (either by exporting as PNG or you can automatically save the SVG next to the process in the workbench repository when you save the process in designer. Your JPanel could retrieve this process PNG or SVG, and annotate it by first querying the current state of your process (from the engine or the audit tables directly) and using that to highlight certain nodes for example.
For the next version of jBPM we're working on a REST call that would automate all of that for you.
I think I am going to use JGraphix to draw my bpm, because as I saw, it give the possibility to draw shapes like bpmn ones.
I didn't see if it allows to change the color of the task case after x minut, but I guess it's going to be possible, and it's going to be the way to represent the evolution of the process at run time.
Do you think it's an Ok idea ?
I'm pretty new to Java web application and I just started a sample project in order to get some experience in this area.
Here's the matter on which I am currently working : let's assume that my web application will display a bunch of items with a grid containing a small picture (thumbnail) for each of them. What are the best or common practices to implement such an application, with consideration for performance issues (here, I'm mainly thinking about the payload size every time a user would load the list of items)?
Do we usually create a smaller size copy of the uploaded image files, or do we use some Javascript, CSS transformation, you name it, to reduce the images to display?
FYI, I'm using Spring MVC for my sample project.
Hope my question was clear enough. Thx in advance.
The best way is to create a separate thumbnail file for each picture when uploaded. When your client will display your gallery, he will only get reduced picture, and then save a lot of download and presentation time
I am using a java applet in my web project and some images are shown in this java applet.
I want to limit users to pull images from the web page. What are possible techniques for a client user to save images used in a java applet which is used in a browser session, except "print screen"?
Any ideas are welcome.
Thanks.
..What are possible techniques for a client user to save images used in a java applet
I don't know about typical end-users, but I'd do these things to circumvent several security strategies:
1. Hide them in the archives
Look at the source of the page
Discover the location of the Jars
Download each one by direct fetch
Rename them to .zip and expand them (quick & dirty), then..
Sell your images for causing me that much inconvenience to get them in the form I want.
That last part was sarcasm (mostly), but just wanted to make the point that if you put something in a Jar, people can get it out.
2. Hide them on the server
Use a packet sniffer to discover the image locations by URL.
Pull each image directly (etc.)
3. Encrypt the images
You might use techniques to encrypt the images, then obfuscate the code that decrypts them, but that would also fail against a determined hacker.
4. Screen grab
As mentioned already. 'Last resort' - crude, but effective.
..Any ideas are welcome.
Don't pursue such strategies. You won't achieve any form of security worth having, it will just irritate the user.
If the image is a bitmap inside of a jframe it'll be hard to capture it without resorting to a screen grab. Just like using it in flash the image file itself won't actually exist anywhere on the client.
After scouring the web I have edited my question from the one below to what it is now.
Ok I seem to understand that I don't need all the capabilities of excel right now. I think i am satisfied having a data grid to display data. Basically i am working on Struts 2 and I wat my jsp page to have an excel like feel and hence looks like even a datagrid is sufficient. I came across This Technology
I am not sure whether I must go ahead and use it. Any other suggestions, alternatives are welcome
The older version of the question
"I have a java web application running on windows currently. I may host it in future in a Linux Server.
My application allows people to upload data. I want to display the data they have uploaded in an excel file and render it in a portion of my webpage.
How do I go about this ?"
Basically you would need to read the excel files, get the data in some kind of java objects, and then show it back to user as a normal HTML page with tables etc..
If you want to show the excel files in such a way that your users are also able to edit these then you need to look into javascript / ajax to make a UI as per your needs.
An easy and open source way of reading the uploaded excel files in java is via Apache POI. It is capable of reading .xls files as well as the newer OOXML .xlsx files.
http://poi.apache.org/spreadsheet/
They have very helpful examples which can get you started within 10 minutes..
http://poi.apache.org/spreadsheet/quick-guide.html
If you can allow data to go to another site, then you can use ZOHO. Their online Excel Editing is reasonably good and you don't really have to do anything much.
Maybe you can try http://www.jxcell.net:
It is a java spreadsheet component which allow you to edit your Excel via web page.