Hello,
Please explain what is the difference between Factory and Formatter function. Because as I see both can be used to format or manipulate the output results. How to choose between both of them ?
Regards,
Mayank
Factory functions allows you to create different types of controls in runtime. Let's assume that you have a list and you want to display different type of list items according to your list index for instance, or maybe to some value that you have in your model. Factory functions allows you to do it in the binding way.
Formatters are some kind of an helper functions which receive and input and return an output. The most popular examples are date and time that you receive date in form A and return date in form B. formatter functions are defined on a property level so if you have a field in your list item which display a date you can use formatter in order to do a very simple manipulation to this date
Related
I was looking inside the create_vlabel function and noted that to get the graph_name and label_name it is used graph_name = PG_GETARG_NAME(0) and label_name = PG_GETARG_NAME(1). Since these two variables are also passed as parameters, I was thinking that, if I wanted to add one more parameter to this function, then I would need to use PG_GETARG_NAME(2) to get this parameter and use it in the function's logic. Is my assumption correct or do I need to do more tweaks to do this?
You are correct, but you also need to change the function signature in the "age--1.2.0.sql" file, updating the arguments:
CREATE FUNCTION ag_catalog.create_vlabel(graph_name name, label_name name, type new_argument)
RETURNS void
LANGUAGE c
AS 'MODULE_PATHNAME';
Note that all arguments come as a "Datum" struct, and PG_GETARG_NAME automatically converts it to a "Name" struct. If you need an argument as int32, for example, you should use PG_GETARG_INT32(index_of_the_argument), for strings, PG_GETARG_CSTRING(n), and so on.
Yes, your assumption is correct. If you want to add an additional parameter to the create_vlabel function in PostgreSQL, you can retrieve the value of the third argument using PG_GETARG_NAME(2). Keep in mind that you may need to make additional modifications to the function's logic to handle the new parameter correctly.
The answers given by Fahad Zaheer and Marco Souza are correct, but you can also create a Variadic function, with which you could have n number of arguments but one drawback is that you would have to check the type yourself. You can find more information here. You can also check many Apache Age functions made this way e.g agtype_to_int2.
I do use NatTables with GlazedLists. I can not find in documentation, how default comparator compares values. According ASCII code values?
If you have not configured any other Comparator for a column, NatTable will use its DefaultComparator. The DefaultComparator checks if both objects are of type Comparable, if so it will use the compareTo(String) method of that type. If not it will try to get the String representation of the object and perform a comparison based on that. String itself is also a Comparable so you find the detailed information how Strings are compared in the Javadoc.
how can i subtract number of days (timestamp|date'z') from current day (date('z')) in latte? I've tryes to use var but that does not like the formating (z).
Latte filters, unlike function calls, are not something that can be applied to any part of an expression – they are only optional feature of the variable printing macro.
{expression_to_be_printed|filter1|filter2|filter3}
date filter mostly just calls format method so you can use it directly:
{(new DateTime())->format('z') - $timestamp->format('z')}
This, however, will not work if the $timestamp lies in a different year.
To fix this, you can use DateTime’s diff method. DateInterval, returned by the method, can then be formatted using format method which provides difference in the number of days through %a formatting string.
{$timestamp->diff(new DateTime())->format('%a')}
Fortunately, the date filter also allows formatting intervals.
{$timestamp->diff(new DateTime())|date:'%a'}
Admittedly, this looks kind of ugly. A better way would be to define a custom filter so you could just use {$post->timestamp|daysAgo}. See Latte docs about creating your own filters.
For example in the following article
http://www.artima.com/weblogs/viewpost.jsp?thread=179766
Two separate examples are given:
Automatic string conversion
Addition of append method
Suppose I want to have automatic string conversion AND a new append method. Is this possible? I have been trying to do both at the same time but I get compile errors. Does that mean the two implicits are conflicting?
You can have any number of implicit conversions from a class provided that each one can be unambiguously determined depending on usage. So the array to string and array to rich-array-class-containing-append is fine since String doesn't have an append method. But you can't convert to StringBuffer which has append methods which would interfere with your rich array append.
I need to fill a field in a report based on the end result of a complex branching statement. How do I do this in iReport? The report needs to show a different string depending on what is in different fields in the database. Do I make a really complex SQL statement? Do I use variables?
So, for instance,
If field x=1
IF y=1
IF z=1
Field should read A
If x=1
IF y=1
IF z=2
Field should read B
You could do something similar to the following:
( $F{staff_type} == null ? new String("") :
( $F{staff_type}.equalsIgnoreCase("Permanent") ? new String("1") :
( $F{staff_type}.equalsIgnoreCase("Non-permanent") ? new String("2") : new String("")
)))
Basically, you need to use nested condition expressions.
in the textfieldexpression write an expression like this
(($F{PAYMENTMODE}.equals("CS")) ? "Cash":($F{PAYMENTMODE}.equals("CQ"))? "Cheque":"Bank")e
I think the easiest way to do this would be to have the field(s) filled by a parameter passed from the backing bean. The jdbc connection is created in the bean and passed to the report, it should be relatively easy to access the field or fields you need and run the data through a method which determines the branching outcome. Assign the outcome to the parameter and pass it to the report in the jasperParameter variable of JasperFillManager.fillReport(file, parameters, jdbcConnection).
Usually, I handle all the programming logic before passing the data to the Jasper Report Engine, but in some cases, post-processing or post-checking is required. If it is that scenario and If I had MANY cases (strings) to check, I would code a 'Jasper Report Scriptlet' and handle that logic there (so that the code/report is readable and maintainable and also for code reuse). If it is just 2 or 3 strings to check, I would use the 'Ternary' operator.
If you want to use report scriptlet, create a scriptlet class (or use an existing one), code a method to handle this logic (Ex: 'checkString' method) and put $P{REPORT_SCRIPTLET}.checkString(someString) in the TextField's expression.