Questions tagged [wrapper]
A wrapper is an OOP technique where an object encapsulates (wraps) another object, resource (dynamically allocated memory, OS file/widow handle, socket, thread mutex, etc) or a set of subroutines, hiding/protecting it and providing another (possibly easier to use) interface. When using this tag on implementation heavy questions - tag the code language the implementation is written in.
wrapper
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How to use C++ in Go
In the new Go language, how do I call C++ code? In other words, how can I wrap my C++ classes and use them in Go?
- 65.5k
201
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7
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Java: Integer equals vs. ==
As of Java 1.5, you can pretty much interchange Integer with int in many situations.
However, I found a potential defect in my code that surprised me a bit.
The following code:
Integer cdiCt = ...;
...
- 18.7k
148
votes
7
answers
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Cannot add task 'wrapper' as a task with that name already exists
When installing 'react-native init AwesomeProject' I get this error when I run react-native run-android:
Could not determine java version from '11.0.1'.
A quick google suggests I need to update the ...
- 1,511
120
votes
11
answers
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When to use wrapper class and primitive type
When I should go for wrapper class over primitive types? Or On what circumstance I should choose between wrapper / Primitive types?
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5
answers
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How to decorate all functions of a class without typing it over and over for each method? [duplicate]
Lets say my class has many methods, and I want to apply my decorator on each one of them, later when I add new methods, I want the same decorator to be applied, but I don't want to write @mydecorator ...
- 5,292
100
votes
6
answers
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Developing C wrapper API for Object-Oriented C++ code
I'm looking to develop a set of C APIs that will wrap around our existing C++ APIs to access our core logic (written in object-oriented C++). This will essentially be a glue API that allows our C++ ...
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92
votes
5
answers
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Vue - how to pass down slots inside wrapper component?
So I've created a simple wrapper component with template like:
<wrapper>
<b-table v-bind="$attrs" v-on="$listeners"></b-table>
</wrapper>
using $attrs and $listeners to ...
- 6,872
84
votes
11
answers
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Can you alter a Javascript function after declaring it?
Let's say I have var a = function() { return 1; }. Is it possible to alter a so that a() returns 2? Perhaps by editing a property of the a object, since every function is an object?
Update: Wow, ...
- 21.9k
78
votes
14
answers
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Making decorators with optional arguments [duplicate]
from functools import wraps
def foo_register(method_name=None):
"""Does stuff."""
def decorator(method):
if method_name is None:
method.gw_method = method.__name__
...
- 56.5k
77
votes
10
answers
80k
views
General decorator to wrap try except in python?
I'd interacting with a lot of deeply nested json I didn't write, and would like to make my python script more 'forgiving' to invalid input. I find myself writing involved try-except blocks, and would ...
- 19.4k
76
votes
3
answers
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How to test an internal class in a class library?
I would like to write a class library which creates for me a complex object but should only be exposed as little as possible. I want it to be included into other projects and there I only have one ...
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69
votes
8
answers
27k
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Using == operator in Java to compare wrapper objects
I'm reading SCJP Java 6 by Kathy Sierra and Bert Bates and this book is confusing me so much. On page 245 they state that the following code below.
Integer i1 = 1000;
Integer i2 = 1000;
if(i1 != i2)
...
- 3,377
59
votes
5
answers
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How many objects are created by using the Integer wrapper class?
Integer i = 3;
i = i + 1;
Integer j = i;
j = i + j;
How many objects are created as a result of the statements in the sample code above and why? Is there any IDE in which we can see how many ...
- 826
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votes
5
answers
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What is the meaning of a C++ Wrapper Class?
I have a little trouble in understanding a wrapper class. It would be great if some one could help providing apt examples.
What is a C++ Wrapper Class and what are the circumstances of writing it ?
...
- 34.4k
48
votes
5
answers
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How to convert Integer[] to int[] array in Java?
Is there a fancy way to cast an Integer array to an int array?
(I don't want to iterate over each element; I'm looking for an elegant and quick way to write it)
The other way around I'm using
...
- 3,938
48
votes
3
answers
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What's the relative order with which Windows search for executable files in PATH?
If I have a.com, a.cmd, a.bat, and a.exe files in my %PATH%, which one would Windows pick if I invoke just the command a? Is this officially spec-ed somewhere by Microsoft?
I just wanted to wrap my ...
- 2,189
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10
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How to safely wrap `console.log`?
Suppose I want to include some calls to console.log for some legitimate production reason, say for something like a unit test harness. Obviously I would not want this to throw a premature exception if ...
- 76.4k
48
votes
2
answers
98k
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Creating simple c++.net wrapper. Step-by-step
I've a c++ project. I admit that I'm a complete ZERO in c++. But still I need to write a c++.net wrapper so I could work with an unmanaged c++ library using it. So what I have:
1) unmanaged project's ...
- 642
43
votes
3
answers
8k
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Exposing `defaultdict` as a regular `dict`
I am using defaultdict(set) to populate an internal mapping in a very large data structure. After it's populated, the whole structure (including the mapping) is exposed to the client code. At that ...
- 51.2k
41
votes
6
answers
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How do I wrap a function in Javascript?
I'm writing a global error handling "module" for one of my applications.
One of the features I want to have is to be able to easily wrap a function with a try{} catch{} block, so that all calls to ...
- 31.9k
41
votes
3
answers
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Parent div is smaller than child div?
here's my question, i want to fill the content div with white. BUT when i do it , its not filling the whole div. The child div are more bigger and they go over the parent div (content). I want that ...
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2
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What is the difference between a wrapper, a binding, and a port?
In a software portability context, what is the difference between these three concepts?
For example, I want to use the ncurses library, the original ncurses library is written in C, but my ...
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votes
8
answers
29k
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Simple way to get wrapper class type in Java
I have a piece of code where I need to pass the class of a field in a method. Because of the mechanics of my code I can only handle reference objects and not primitives. I want an easy way of ...
- 11.5k
37
votes
2
answers
16k
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Java: Is there a difference between L and l (lowercase L) when specifying a long?
When I specify a number to be a long with a constant value 400, is there any difference between using 400L and 400l?
Does it have some relationship to the wrapper type? Is L used to get a wrapper ...
- 371
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votes
3
answers
13k
views
How to wrap a function using varargin and varargout?
mini-example:
function varargout = wrapper(varargin)
varargout = someFunction(varargin);
That's how I'd do it first. But for example if someFunction = ndgrid this yields a not defined for cell ...
- 26.8k
31
votes
3
answers
29k
views
How to wrap every method of a class? [duplicate]
I'd like to wrap every method of a particular class in python, and I'd like to do so by editing the code of the class minimally. How should I go about this?
- 3,368
30
votes
3
answers
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wrapper printf function that filters according to user preferences
My program writes to a log and to stdout. Every message, however, has a certain priority and the user specifies in Preferences which priorities go to which stream (log or stdout).
unsigned short ...
- 1,246
29
votes
6
answers
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What is the radix parameter in Java, and how does it work?
I understand that radix for the function Integer.parseInt() is the base to convert the string into. Shouldn't 11 base 10 converted with a radix/base 16 be a B instead of 17?
The following code prints ...
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votes
6
answers
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How to fake type with Python
I recently developed a class named DocumentWrapper around some ORM document object in Python to transparently add some features to it without changing its interface in any way.
I just have one issue ...
- 6,134
28
votes
2
answers
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Does C++11 have wrappers for dynamically-allocated arrays like Boost's scoped_array?
I often need to deal with dynamically-allocated arrays in C++, and hence rely on Boost for scoped_array, shared_array, and the like. After reading through Stroustrup's C++11 FAQ and the C++11 ...
- 14.6k
27
votes
1
answer
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BOOL wrapper? Make an object of `BOOL` value. (Objective-C)
How do I wrap a BOOL in an object type in Objective-C?
I want to store a BOOL in the userInfo object of an NSTimer. How do I wrap it?
- 9,971
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votes
3
answers
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Automatically generate C# wrapper class from dll in Visual Studio 2010 Express?
I was told by a colleague of mine that Visual Studio allows one to point to a .dll and auto-magically generate a C# wrapper class. Is this really possible? And if so, how does one go about achieving ...
- 44k
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votes
11
answers
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Java vs. C++ for building a GUI which has a C++ backend [closed]
I currently have a C++ backend that I need to connect with a GUI, and since I've never built a GUI before, I was confused on where to start.
I'm comfortable writing code in C++ and Java, so I'd ...
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votes
1
answer
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vue wrap another component, passing props and events
How can I write my component to wrap another vue component, while my wrapper component get some extra props? My wrapper template component should be:
<wrapper-component>
<v-table><...
- 6,872
25
votes
3
answers
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views
What is the best way to call into Swift from C?
Calling into C from Swift is pretty simple, however I'm looking into making a bi-directional wrapper in C, so my C has to call Swift functions.
Right now, I can do this by declaring function pointers ...
- 1,298
24
votes
2
answers
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views
How to implement a builder class using Generics, not annotations?
I want to write a generic builder class which wraps around any java class and providing setter functions of a specific style. I am not sure if this could be called "dynamically generated functions".
...
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23
votes
4
answers
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Are all primitive wrapper classes immutable objects?
Are all primitive wrapper classes in Java immutable objects? String is immutable. What are the other immutable objects?
- 15k
23
votes
5
answers
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Java Wrapper equality test
public class WrapperTest {
public static void main(String[] args) {
Integer i = 100;
Integer j = 100;
if(i == j)
System.out.println("same");
else
...
- 39.3k
23
votes
4
answers
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Rule of thumb for naming wrapper classes
I find myself creating a significant number of wrapper classes, purely because I want to mock out the behaviour of
Classes that don't lend themselves well to the RhinoMocks isolation model (for ...
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votes
1
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Why is this method overloading ambiguous?
public class Primitive {
void m(Number b, Number ... a) {} // widening, autoboxing->widening->varargs
void m(byte b, Number ... a) {} // unboxing, autoboxing->widening->varargs
...
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votes
5
answers
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Generate C wrapper from C++?
I want to generate C wrappers from C++ libraries.
There are tutorials on how to do it by hand:
http://dsc.sun.com/solaris/articles/mixing.html
http://www.parashift.com/c++-faq-lite/mixing-c-and-cpp....
- 475
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3
answers
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Is there a way to autogenerate wrappers in Eclipse?
I have to create several proxies, to add, for example, logging. Something like that:
interface IMath {
public int add(a, b);
}
class Math implements IMath {
public int add(a, b) { return a + ...
- 2,119
22
votes
3
answers
8k
views
Fast implement wrapping (delegate methods) in Eclipse?
Is there some template or something to implement iterface methods with accessing to wrapped member?
For example, suppose I have
public class MyClass implements List<Something> {
private ...
- 29.8k
22
votes
1
answer
15k
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Using Streams with primitives data types and corresponding wrappers
While playing around with Java8's Streams-API, I stumbled over the following:
To convert an array of primitive wrapper classe objects into a Stream I just have to call Stream.of(array). But to ...
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votes
3
answers
13k
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Fragments - Do you have to use an Activity Wrapper around a fragment which comprises the whole Activity?
Consider the sample app from developers.android.com
This describes using Fragments like so:
On a Phone you can use Fragment 1 on Activity A and fragment 2 on Activity B.
On a tablet you have more ...
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21
votes
8
answers
11k
views
Comparing wrapper class with primitive using equals() gives strange behavior
Consider below code snap.
we use equals() to compare objects are meaningfully equivalent or not ?
Here both value are meaningfully equal but why does longWrapper.equals(0) return false ?
And when I ...
- 1,310
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votes
4
answers
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Tesseract 3 (OCR) - .NET Wrapper
http://code.google.com/p/tesseractdotnet/
I am having a problem getting Tesseract to work in my Visual Studio 2010 projects. I have tried console and winforms and both have the same outcome. I have ...
- 1,537
20
votes
7
answers
8k
views
Why Java does not allow null while declaring primitive data types [duplicate]
This is in continuation to my previous question and accroding to answers of this question Declaration of wrapper classes
Java wraps primitive data type to wrapper classes then why
char c = null; // ...
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votes
6
answers
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Are Java wrapper classes really immutable?
Java Wrapper classes are supposed to be immutable. This means that once an object is being created, e.g.,
Integer i = new Integer(5);
its value cannot be changed. However, doing
i = 6;
is ...
- 4,144