Introducing OpenLaszlo 4
Although of interest, this list would be made more useful if a single click on the client name produced another window within the browser containing the rest of the client's data. Arranging for this behaviour is not difficult. The first thing we need to do is provide some visual feedback to our users as they select a client name from the first window. Add this code to the window's <text> element:
<handler name="onclick"> client_info.datapath.setFromPointer( this.datapath ); </handler> <handler name="onmouseover"> this.setBGColor( 0xBBBBFF ); </handler> <handler name="onmouseout"> this.setBGColor( null ); </handler>
<window name="client_info" x="300" y="100" width="300" height="200" title="Client Specifics"> <datapath/> <text datapath="../address/text()" width="100%" multiline="true" /> <text datapath="../contact_tel_no/text()" fontsize="16"/> <text datapath="../email_address/text()" fontsize="14"/> <simplelayout/> </window>
This window has its own name and title values, as well as x, y, width and height values that position it initially to the right of the client listing window. It also has a datapath tag, together with three text elements that reference (using an appropriate XPath specification) the other data elements within our database table. We've specified that the address uses the entire width of the client_info window and can word wrap, while the other two pieces of data are displayed in differently set font sizes. When this LZX application (called clients2.lzx) is loaded into the browser, the client list appears in the original window, and as each client name is clicked, the second window refreshes to display the address, telephone number and e-mail address of the currently selected client. If you are following along, note how the user receives visual feedback as each client name is clicked. Figure 4 shows an example, with one client name highlighted (clicked) and the associated details appearing in the second window.
Let's finish this example with a bit of fun by adding some LZX animation effects to our OpenLaszlo application. Specifically, whenever users click on a client name in the first window, in addition to refreshing the data, we want the second window to roll up (shrink), pause, and then roll back down again (grow). To make this work, we need to wrap the onclick handler code with calls to our animators:
<handler name="onclick"> client_info.winShrink.doStart(); client_info.datapath.setFromPointer( this.datapath ); client_info.winGrow.doStart(); </handler>
Specifying animation with LZX involves writing XML. Here's the shrinking and growing LZX code for this application (which I've called client3.lzx). This code is added to the second window's XML:
<animatorgroup name="winShrink" start="false" duration="0"> <animator attribute="height" to="50"/> <animator attribute="height" to="50"/> </animatorgroup> <animatorgroup name="winGrow" start="false" duration="200"> <animator attribute="height" to="200"/> <animator attribute="height" to="200"/> </animatorgroup>
I define two animatorgroups and give each of them a name. Note how the animatorgroup name is referenced within the onclick handler, above. Within each animatorgroup, I provide some timing data (duration) and new attribute values for the height of the window. When the window shrinks, the height drops to 50 pixels. When the window grows, the height rises to 200 pixels. When combined, the visual effect is that of the window rolling up, pausing, then rolling back down to display the updated client details. Unfortunately, I can't show this in a screenshot, so you'll have to try it to see the effect in action (or take my word for it). The main point, of course, is that the visual effect has been realised without writing code, per se. All I did was define the behaviour I wanted in LZX.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide