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How to inherit constructors?
Imagine a base class with many constructors and a virtual method
14 Answers
14
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Is it unnecessary to put super() in constructor?
...) is a compiler error so it must be specified.
For example:
public class Base { }
public class Derived extends Base { }
This is fine because if you add no constructor explicitly Java puts in a public default constructor for you.
public class Base { }
public class Derived extends Base { public D...
Check if a table exists in Rails
...tables/views, collectively data sources.
# Tables and views
ActiveRecord::Base.connection.data_sources
ActiveRecord::Base.connection.data_source_exists? 'kittens'
# Tables
ActiveRecord::Base.connection.tables
ActiveRecord::Base.connection.table_exists? 'kittens'
# Views
ActiveRecord::Base.connect...
How to execute a raw update sql with dynamic binding in rails
...ing connection and using it's methods, e.g. for MySQL:
st = ActiveRecord::Base.connection.raw_connection.prepare("update table set f1=? where f2=? and f3=?")
st.execute(f1, f2, f3)
st.close
I'm not sure if there are other ramifications to doing this (connections left open, etc). I would trace the...
What are metaclasses in Python?
...tributes of the class-to-be. The metaclass is determined by looking at the baseclasses of the class-to-be (metaclasses are inherited), at the __metaclass__ attribute of the class-to-be (if any) or the __metaclass__ global variable. The metaclass is then called with the name, bases and attributes of ...
multiple packages in context:component-scan, spring config
...
The following approach is correct:
<context:component-scan base-package="x.y.z.service, x.y.z.controller" />
Note that the error complains about x.y.z.dao.daoservice.LoginDAO, which is not in the packages mentioned above, perhaps you forgot to add it:
<context:component-sca...
nginx: send all requests to a single html page
...
I think this will do it for you:
location / {
try_files /base.html =404;
}
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How do I work around JavaScript's parseInt octal behavior?
...is is a common Javascript gotcha with a simple solution:
Just specify the base, or 'radix', like so:
parseInt('08',10); // 8
You could also use Number:
Number('08'); // 8
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Json.net serialize/deserialize derived types?
... JsonSerializerSettings.
See: how to deserialize JSON into IEnumerable<BaseType> with Newtonsoft JSON.NET
Be careful, though. Using anything other than TypeNameHandling = TypeNameHandling.None could open yourself up to a security vulnerability.
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Cannot hide status bar in iOS7
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in your apps plist file add a row call it "View controller-based status bar appearance" and set it to NO
Note that this simply does not work, if you are using UIImagePickerController in the app.
from http://www.openfl.org/developer/forums/general-discussion/iphone-5ios-7-cant-hide-...