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When should we use Observer and Observable?
...ause it separates the part where you say that the Observable has changed, from the part where you notify the changes. (E.g. Its useful if you have multiple changes happening and you only want to notify at the end of the process rather than at each small step). This is done through setChanged(). So ...
CSS: Truncate table cells, but fit as much as possible
...t;<!--Content here--></div>
<!--Keeps the container from collapsing without
having to specify a height-->
<span>&nbsp;</span>
</div>
</td>
.container {
position: relative;
}
.content {
position: absolute;
max...
How to create and handle composite primary key in JPA
I want to have versions from the same data entry. In other words, I want to duplicate the entry with another version number.
...
Benefits of header-only libraries
...tages of a header-only library:
Bigger object files. Every inline method from the library that is used in some source file will also get a weak symbol, out-of-line definition in the compiled object file for that source file. This slows down the compiler and also slows down the linker. The compiler...
What data type to use for hashed password field and what length?
...ion is not strong enough for storing passwords. You should read the answer from Gilles on this thread for a more detailed explanation.
For passwords, use a key-strengthening hash algorithm like Bcrypt or Argon2i. For example, in PHP, use the password_hash() function, which uses Bcrypt by default.
...
Which encoding opens CSV files correctly with Excel on both Mac and Windows?
...252 for some reason. Be advised that ISO-8859-1 is missing some characters from WINDOWS-1252 as shown here:
| Char | ANSI | Unicode | ANSI Hex | Unicode Hex | HTML entity | Unicode Name | Unicode Range |
| € | 128 | 8364 | 0x80 | U+20AC | &...
What's the difference between and
...lt;?> means anythings. So It can accept of Type which are not inherited from Object class.
<? extends Object>
<? extends Object> means you can pass an Object or a sub-class that extends Object class.
ArrayList<? extends Number> numberList = new ArrayList<Number>(); //...
Passing enum or object through an intent (the best solution)
... intent.putExtra(name, ordinal());
}
public static AwesomeEnum detachFrom(Intent intent) {
if(!intent.hasExtra(name)) throw new IllegalStateException();
return values()[intent.getIntExtra(name, -1)];
}
}
Usage:
// Sender usage
AwesomeEnum.SOMETHING.attachTo(intent);
// Receiver us...
How to equalize the scales of x-axis and y-axis in Python matplotlib?
...
You need to dig a bit deeper into the api to do this:
from matplotlib import pyplot as plt
plt.plot(range(5))
plt.xlim(-3, 3)
plt.ylim(-3, 3)
plt.gca().set_aspect('equal', adjustable='box')
plt.draw()
doc for set_aspect
...
Unsigned keyword in C++
...
From the link above:
Several of these types can be modified using the keywords signed, unsigned, short, and long. When one of these type modifiers is used by itself, a data type of int is assumed
This means that you can...