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Evaluate empty or null JSTL c tags
...c:choose>
Or if you don't need to conditionally render a bunch of tags and thus you could only check it inside a tag attribute, then you can use the EL conditional operator ${condition? valueIfTrue : valueIfFalse}:
<c:out value="${empty var1 ? 'var1 is empty or null' : 'var1 is NOT empty or n...
A Java API to generate Java source files [closed]
... an API. It's not the easiest thing to get information on, but it's there and it works extremely well.
The easiest way to get hold of it is as part of the JAXB 2 RI - the XJC schema-to-java generator uses CodeModel to generate its java source, and it's part of the XJC jars. You can use it just fo...
To draw an Underline below the TextView in Android
...returns Spannable with underline spans, but if you use getString() it will convert the Spannable to String resulting spans being removed.
– Yaroslav Mytkalyk
Nov 10 '14 at 10:01
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Android AsyncTask threads limits?
...e in the phone. For all those operations (updates, retrieving data from db and etc.) I use async tasks. As up till now I didn't see why I shouldn't use them, but recently I experienced that if I do some operations some of my async tasks simply stop on pre-execute and don't jump to doInBackground. Th...
Rails 2.3-style plugins and deprecation warnings running task in Heroku
...eare gives you a nice walkthrough link (found in the page @yuri linked) to convert my simple rails 2.3 plugins to 3.2. I liked this solution because it didn't just silence the warnings, it actually fixes them.
– Jeremiah
Oct 8 '13 at 17:24
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Postgres NOT in array
I'm using Postgres' native array type, and trying to find the records where the ID is not in the array recipient IDs.
7 An...
Concurrent HashSet in .NET Framework?
...t; _data;
This is the recommended option because the type is thread-safe and provide you the same advantages than a HashSet<T> except key and value are different objects.
Source: Social MSDN
ConcurrentBag
If you don't mind about the duplicate entries, you can use the class ConcurrentBag&l...
Drop unused factor levels in a subsetted data frame
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As a side-effect the function converts the data frame to a list, so the mydf <- droplevels(mydf) solution suggested by Roman Luštrik and Tommy O'Dell below is preferable.
– Johan
May 9 '14 at 10:41
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What's the scope of a variable initialized in an if statement?
...nction, class, or module in which they're assigned. Control blocks like if and while blocks don't count, so a variable assigned inside an if is still scoped to a function, class, or module.
(Implicit functions defined by a generator expression or list/set/dict comprehension do count, as do lambda e...
What is the Java equivalent for LINQ? [closed]
... JDK8 called The Power of the Arrow, also NetBeans 8 has great support for converting constructs to JDK8 which I've also blogged about Migrating to JDK 8 with NetBeans.
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