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Visual Studio: How do I show all classes inherited from a base class?
In Visual Studio, How do I show all classes inherited from a base class?
19 Answers
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How do I create an abstract base class in JavaScript?
Is it possible to simulate abstract base class in JavaScript? What is the most elegant way to do it?
16 Answers
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How do I initialize the base (super) class?
...asses are derived from object and are what you are using, and invoke their base class through super(), e.g.
class X(object):
def __init__(self, x):
pass
def doit(self, bar):
pass
class Y(X):
def __init__(self):
super(Y, self).__init__(123)
def doit(self, foo):
return supe...
JavaScript Chart Library
...s of JavaScript solutions for graphics that do not require Flash:
Canvas-based, rendered in IE using ExplorerCanvas that in turns relies on VML
SVG on standard-based browsers, rendered as VML in IE
There are pros and cons of both approaches but for a charting library I would recommend the later ...
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...