I need to generate a PDF417 barcode with error correction level of 5 using Barbecue api.
I generate a PDF417 by calling createPDF417(data) on the BarcodeFactory and this returns a barcode object which is passed to my print formatting class as a ByteArrayOutputStream, but I'm struggling to see how/if it implements any error correction level and if i can set this anywhere. I can see methods in the PDF417Module class (createCodeWords and generateEC) that look like what i'm expecting. I just cant see how the draw method in the PDF417Module class is actually called.
I apologise, I'm a relative novice.
I've had a weekend off and done some drinking and some sleeping and now I see the PDF417Module is instantiated and the method called. I now feel embarrassed for asking.
Related
Just something that has been playing on my mind recently. A java example of what I mean by an inbuilt method: System.out.println("hi");. How does this method actually make 'hi' appear on screen? I can imagine a long series of methods inside methods inside methods, but how would the 'base' method do what it is supposed to?
this is a good example for println. http://luckytoilet.wordpress.com/2010/05/21/how-system-out-println-really-works/
Essentially, the call gets processed through the call stack, until it reaches native code, then you're into OS specific code, i.e. the windows API.
I am brand new to Magento and the documentation, primarily the phpDocs, are difficult to navigate. For example,
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
In the php doc for Class Mage_Eav_Model_Entity_Attribute_Set there is no mention of the method getAttributeSetName() either in inherited methods or otherwise and yet this works.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
echo $attributeSet->getAttributeSetName();
So I suppose I have several questions.
Can someone explain to me why the documentation is this way?
Where I can find the mysterious getAttributeSetName() method in the phpDocs?
My theory is that there is some inheritance or a design pattern implementation going on that I'm not understanding, maybe someone can shed some light on this for me.
If you really want to fry your brain, take a look at the source code for Mage_Eav_Model_Entity_Attribute_Set and follow the inheritance chain all the way back. You won't find a getAttributeSetName method defined anywhere.
All Magento objects that inherit from Varien_Object can have arbitrary data members set on them. Try this.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
$attributeSet->setFooBazBar('Value');
var_dump($attributeSet->getFooBazBar());
var_dump($attributeSet->getData('foo_baz_bar'));
var_dump($attributeSet->setData('foo_baz_bar','New Value'));
var_dump($attributeSet->getFooBazBar());
You can also get all the data members by using
var_dump($attributeSet->getData());
but be careful dumping these, because if there's a data object that has a circular reference and you're not using something like xDebug, then PHP will have a fit trying to display the object.
Magento stores data properties in a special _data array property. You can get/set values in this array with getData and setData. Magento also has implemented magic getting and setter methods, so when you say something like
$object->getFooBazBar();
The method getFooBazBar is transformed into the data property foo_baz_bar. and then getData is called using this property. It's a little tricky to get your head around, but once you get it you'll start to see how much time you can save using this pattern.
One side effect of this is, of course, it's impossible to infer what data properties any object might have by looking at it's class file, so there's no phpDocs for these methods.
I have been trying to use BLToolkit to activate an Oracle stored procedure which takes a User Defined Type as an argument as an output parameter and changes it.
I have managed to do this on a primitive type, and and also by manually calling SetSpCommamd however I would like to use the abstract class generation method but can't seem to get it to work.
I'm pretty sure the code I wrote is correct (works for the primitive). When debugging I found the SetSpCommamd called by the generated code gets wierd parameters instead of the ones I provided as opposed to when I call the method manually (the it gets the exact parameters I'd like). I wish I could see the code generated by the reflection emit to see what's wrong there.
Can anyone please help me figure out why this is not working?
Found the problem (Potentially a bug in BLToolkit).
BLToolkit does not pass the UDT Class as is to the procedure (instead it tries to flatten it or something and pass the insides of the object). I Changed the object to a Struct instead of a Class and that fixed it.
Later on I also changed it back to class and made a patch in the 'IsScaler()' method in BLToolkits code.
I will report this as a Bug I hope they fix it.
I'm currently writing an application that plays podcasts. I'm representing all the feeds and the episodes within them as QStandardItem objects within a QStandardItemModel. Right now, I don't have a way to save this model--when the application closes, the feed model goes up in smoke. I looked at using QSettings, but that only works for datatypes that fall under QVariant.
Looking at this post gave me some hope, but I think I'm doing something wrong. I've got the following code in the constructor for my application.
//Expand QVatiant to use QStandardItemModel
qRegisterMetaType<QStandardItemModel>("QStandardItemModel");
That, however, gives me this error at compile time.
/ [...] QtSDK/Desktop/Qt/4.8.1/gcc/lib/QtGui.framework/Versions/4/Headers/qstandarditemmodel.h:424: error: 'QStandardItemModel::QStandardItemModel(const QStandardItemModel&)' is private
Ah. That reminds me of this caveat from the Qt documentation for QMetaType, here.
Any class or struct that has a public default constructor, a public copy constructor and a public destructor can be registered.
So, where do I go from here? Qt is behaving exactly as it should, so this approach won't work. I'm thinking of saving off the model as an xml file, but that seems like a ton of effort. This seems like a pretty common problem--I just don't know where to look for the answer.
Here's the best solution I could come up with: Create a method that saves the model into an XML document, and call it whenever I change the model (e.g. add or remove a podcast). I don't have the actual source code on hand, but since there's no real easy way to save the data structure wholesale, this is the best solution.
I'm looking at some code I've written and thinking "should I be passing that object into the method or just some of its properties?".
Let me explain:
This object has about 15 properties - user inputs. I then have about 10 methods that use upto 5 of these inputs. Now, the interface looks a lot cleaner, if each method has 1 parameter - the "user inputs object". But each method does not need all of these properties. I could just pass the properties that each method needs.
The fact I'm asking this question indicates I accept I may be doing things wrong.
Discuss......:)
EDIT: To add calrity:
From a web page a user enters details about their house and garden. Number of doors, number of rooms and other properties of this nature (15 in total).
These details are stored on a "HouseDetails" object as simple integer properties.
An instance of "HouseDetails" is passed into "HouseRequirementsCalculator". This class has 10 private methods like "calculate area of carpet", "caclulateExtensionPotential" etc.
For an example of my query, let's use "CalculateAreaOfCarpet" method.
should I pass the "HouseDetails" object
or should I pass "HouseDetails.MainRoomArea, HouseDetails.KitchenArea, HouseDetails.BathroomArea" etc
Based on my answer above and related to your edit:
a) You should pass the "HouseDetails"
object
Other thoughts:
Thinking more about your question and especially the added detail i'm left wondering why you would not just include those calculation methods as part of your HouseDetails object. After all, they are calculations that are specific to that object only. Why create an interface and another class to manage the calculations separately?
Older text:
Each method should and will know what part of the passed-in object it needs to reference to get its job done. You don't/shouldn't need to enforce this knowledge by creating fine-grained overloads in your interface. The passed-in object is your model and your contract.
Also, imagine how much code will be affected if you add and remove a property from this object. Keep it simple.
Passing individual properties - and different in each case - seems pretty messy. I'd rather pass whole objects.
Mind that you gave not enough insight into your situation. Perhaps try to describe the actual usage of this things? What is this object with 15 properties?, are those "10 methods that use upto 5 of these input" on the same object, or some other one?
After the question been edited
I should definitely go with passing the whole object and do the necessary calculations in the Calculator class.
On the other hand you may find Domain Driven Design an attractive alternative (http://en.wikipedia.org/wiki/Domain-driven_design). With regard to that principles you could add methods from calculator to the HouseDetails class. Domain Driven Design is quite nice style of writing apps, just depends how clean this way is for you.