Vertical Scrolling in JSF Datatables

The vertical scrollbar on the ICEFaces ace:dataTable is flakey, though pagination works fine. This is apparently also true of PrimeFaces, and probably other JSF frameworks. To enable a scrollbar without pagination, a workaround is to set scrolling=false, and then wrap the datatable in a div:

    <div style="overflow:auto;width:100%;height:180px;">
        <ace:dataTable ...>
        </ace:dataTable>
    </div>

The simplest way to add tooltips to ICEFaces components:

As the first tag within the enclosing <h:form>, add
        <ace:tooltip id="tooltip" global="true" speechBubble="true"/>

For each component, add the attribute
        title="tooltip text"
Where, of course, "tooltip text" is the actual text you want displayed.


For <ace:menuItem> components, instead of title, use the attribute helpText.


The global attribute specifies that tooltips should be created for all elements that have a title or helpText attribute. The speechBubble attribute adds a directional indicator that seems useful to me. I assume this works similarly with other JSF libraries.


Styling for the tool tips is done via ui-tooltip. Example CSS:
        .ui-tooltip { font-size:12px; }


It looks like the RichFaces version may have more options, but more complexity. In fairness, I've
not dug deeply into RF, as I am implementing in IF.

Bang Important

When using a framework that in some cases does weirdly nested stuff that overrides your CSS (I'm looking at you, ICEFaces), the CSS directive !important can be your friend. But maybe it's the sort of friend you need to keep a close eye on.

This is something it took me days to find documentation for, and certainly could cause a maintenance headache, but it falls into the the good-to-know category.

Case in point: with an ICEFaces ace:dataTable, displaying multiple rows from a database query, the table would not display the full number of rows, even though it was sufficiently large to do so, because the <div> that contains all the rows, class name ui-datatable-scrollable-body, was getting its max-height set to 100px, no matter what I did. This was enough to show three of four rows. I was finally able to get it to work with this CSS entry:

.ui-datatable-scrollable-body { max-height:250px!important; }

I may have to do some further tweaking so as not to torch any other datatables I may use elsewhere in the application, but at least now I can move forward. And I'll keep glancing over my shoulder, making sure this helper doesn't try to stab me in the back.

Nobody is singing the Aria.

The lack of clear and readily available documentation for support of Section 508, WAI-ARIA, and other accessibility standards in the various JSF libraries, such as ICEfaces and PrimeFaces, is shocking, and really pretty shameful.

Given that the support of user with various disabilities is not only the morally and ethically right thing to do, but in many cases is actually required by law in the US and most other countries, it points to a lack of interest by those privileged to not have to deal with those disabilities.

I suppose that means me, too.

SOP

What do you call it when the person knowledgeable on an legacy technology retires, there is not a replacement hired yet, and then an internal customer requests enhancements involving that technology and some other legacy systems?

Oh, yea, and the development environment for that legacy system has gone AWOL? And then your manager's manager very publicly put you in charge of dealing with it?

Oh, yea, business as usual.

Viewing fake composites, or compositing fake views

Using Hibernate to retrieve data from a database view that contains a join can be tricky, as Hibernate expects there to be a unique primary key. The trick is to fake a composite key using the @Embeddable annotation in a PK model class that contains the properties/@Column references chosen for the composite key, and a the @EmbeddedId annotation in the main model class to include the PK class as the id property.

There's lots of documentation in cyberspace on the syntax for that, but there's one piece that almost all of them miss, and that is how you actually reference the properties that are defined in the @Embeddable compound key class.

First, do not duplicate the properties in both models; they should only occur in the PK model. The PK class is defined as a property of the main model class, so the reference is model.id.property for each element of the CK, instead of model.property.

I created accessors in the main model for the key properties that test that there is an instance of the PK model defined, primarily for testing. Example:

    public String getFirstName() {
        if ( null == this.id ) {
            return null;
        }
        return this.id.getFirstName();
    }

    public void setFirstName(String firstName) {
        if ( null == this.id ) {
            this.id = new ErmsDocOrgPrsnDetailPK();
        }
        this.id.setFirstName( firstName );
    }

It remains to be seen whether those will actually be needed.

Java object cloning

A note to myself from 15 August 2014:

To quickly clone an java object, including all the children and relationships, use SerializationUtils in Apache Commons Lang:

MyObject newObject = (MyObject) SerializationUtils.clone(objectToClone);

(http://www.kianworknotes.com/2014/08/how-to-quickily-clone-object-in-java.html)

Genesis

So, here I am at the genesis of a new blog, which I created on a whim as a way to share some of the developer notes I've been saving for a while, as well as new thoughts and ideas that apply to the use of analytical engines (which some call computers).

I recently found these 10 Rules to Be a Better Programmer, and thought the list to be a pretty good summation of some things I've learned, and am still learning. My comments are italicised (and use Java terminology, but are mostly generalisable).

1. Don't repeat yourself
   This takes some wisdom, but in general it's true. If you find yourself writing the same bit of code more than a handful of lines more than twice, it's time to encapsulate.
2. Name your variables to say what they are for, not what data type they are.
   Yes! Hungarian notation is anathema left over from the bad old days of using tonnes of global variables! If you can't remember the data types of your variables, your routines are too big! Variables (and packages, interfaces, classes, enumerations) should be nouns or noun phrases. A special exception applies to loop counter variables, where "i", "j", "k", and so forth may used by long-standing convention; even there, something like "nameCount" isn't always bad.
3. Give your methods a clear name for what they are going to do.
   See the previous item. Methods should be verbs or verb phrases. Names like "retrieveDocument()" or "isReady()" are good, while "documents()" or "ready()" are not so much.
4. Don't use magic numbers or string literals.
   There are exceptions, but yeah, in general.
5. Write your methods so they can be tested without having any dependencies on other parts of the application, where possible.
   A very good idea. And a good mocking package is a big help.
6. Don't be afraid to ask for help.
   Of these recommendations, I find this one of the most important, and yet I continually forget it. I do count searching via Google, and developer-specific sites like Stack overflow and Code Ranch to be a partial implementation, but I still need to learn to ask people directly.
7. Follow the boy scout rule; fix buggy or messy code; don't leave it for someone else. "Do a good turn daily." But don't fall into the trap of constantly refactoring, and never moving on.
8. Share knowledge with others.
   This is the reciprocation of asking for help. There are many ways to share knowledge, including, oh, I don't know, maybe writing a blog. We'll see how that goes.
9. Don't interrupt your colleagues whilst they are in flow.
   Yes! Working in a cubicle farm does not give you permission, either. Headphones can be a useful indicator.
10. Use criticism as a positive instead of a negative.
    The word "critic" comes to us from a Greek root that has to do with judging, and is related to "crisis". (Etymonline) It's better to mentor and teach via dialogue, I think.