clone

Duplicating a record in Rails 3

由 瘦欲@ 提交于 2019-11-28 03:12:19
问题 I have a prescription model in my Rails 3 application. I am trying to work out the best method of allowing records to be duplicated, but allowing the user to "review" the duplicate before it's saved. I have read a number of questions/answers on SO (such as this one) which explain how to duplicate/clone the record and then save it - but none which explain how to show the form before save. Reading the Rails API is appears the clone method is available. Reading other questions and answers shows

Does C++11's decltype make clone unnecessary?

由 こ雲淡風輕ζ 提交于 2019-11-28 03:03:13
问题 The clone paradigm is used to make a copy of a derived class without casting down to the base class type. Unfortunately, clone must be implemented in each subclass (or with a mixin with CRTP). Is there any chance that C++11's decltype makes this unnecessary? I don't think the code below actually copies original , but simply points a reference to it. When I tried to use new decltype(*original) , I get an error: error: new cannot be applied to a reference type . Is clone still the way to go in

What happens when an Arc is cloned?

由 ▼魔方 西西 提交于 2019-11-28 02:30:06
问题 I am learning concurrency and want to clarify my understanding on the following code example from the Rust book. Please correct me if I am wrong. use std::sync::{Arc, Mutex}; use std::thread; use std::time::Duration; fn main() { let data = Arc::new(Mutex::new(vec![1, 2, 3])); for i in 0..3 { let data = data.clone(); thread::spawn(move || { let mut data = data.lock().unwrap(); data[0] += i; }); } thread::sleep(Duration::from_millis(50)); } What is happening on the line let data = data.clone()

How to clone element with given class name

由 六眼飞鱼酱① 提交于 2019-11-28 02:05:30
I am using getElementById when I need to clone the div element. Code: printHTML( document.getElementById("div_name").cloneNode(true)); Now I need to use getElementsByClassName CloneNode is not working when using getElementsByClassName . How can I put class name in here? Thank's EDIT: When I try to use this: printHTML( $('.dataTables_scroll').clone(true) ); You can see my function: function printHTML(clonedDive){ var iframe = document.createElement("iframe"); document.body.appendChild(iframe); iframe.contentWindow.onunload = function(){ $(".DTTT_container").show("fast"); $("#header_outer").show

How to clone a structure with unexported field?

由 ◇◆丶佛笑我妖孽 提交于 2019-11-28 01:20:59
If I have a type defined as: type T struct { S string is []int } then how can I go about cloning an object of this type? If I do a simple assignment: p := T{"some string", []int{10, 20}} q := p Then any changes made to the []int affect both objects. Since T.is is not exported, it cannot be copied over explicitly, even if extracted using reflect. I'm currently supplying a Clone method in the package of the type itself. But that doesn't help with similar types in other packages. Is there another way to do this? You can't. That's the point of unexported fields: only the declaring package can

What is the use of cloneable interface in java?

由 落爺英雄遲暮 提交于 2019-11-28 01:09:13
What is the use of implementing a cloneable interface as it is a marker interface? I can always make a public Object clone() method in my class. What is the actual purpose of cloneable interface? Bhesh Gurung That's because the clone() method throws CloneNotSupportedException if your object is not Cloneable . You should take a look at the documentation for clone() method. Following is how clone() method is declared in the class Object : protected Object clone() throws CloneNotSupportedException Note: Also, it's been realized that Clone is broken. This answer here in SO explains why and how you

Is there a generic method for cloning CLOS objects?

由 旧街凉风 提交于 2019-11-28 00:46:14
问题 I'm looking for a way to clone CLOS objects in a shallow manner, so the created object would be of the same type with the same values in each slot, but a new instance. The closest thing I found is a standard function copy-structure which does this for structures. 回答1: There is no standard predefined way to copy CLOS objects in general. It is not trivial, if possible at all, to provide a reasonable default copy operation that does the right thing (at least) most of the time for arbitrary

Is there a simple way to “git describe” a remote repository?

由 独自空忆成欢 提交于 2019-11-28 00:27:43
问题 I want to execute the following command on a remote server: git archive --prefix="$tag/" --remote="ssh://$gitserver/var/git/$repo" "$tag" | tar -xvf- The problem is I don't know what $tag is. It should be the output of git describe --abbrev=0 on an up-to-date clone, but I don't know how to get that information without making a local clone of the repository. Is it possible to do this without making a local clone? 回答1: The only way you could start parsing for your tag, without adding too much

Cloning Objects in VBA?

由 99封情书 提交于 2019-11-28 00:27:31
问题 Is there a generic way to clone objects in VBA? So that i could copy x to y instead of copying just the pointer? Dim x As New Class1 Dim y As Class1 x.Color = 1 x.Height = 1 Set y = x y.Color = 2 Debug.Print "x.Color=" & x.Color & ", x.Height=" & x.Height By generic i mean something like Set y = CloneObject(x) rather than having to create my own method for the class copying its properties one by one. 回答1: OK, here's the beginning of something that illustrates it: Create a class, call it, oh,

Why to override clone method in Java

由 倾然丶 夕夏残阳落幕 提交于 2019-11-27 23:35:28
问题 I am confused regarding overriding clone method in the class for which I want cloned object. Object class has protected object method and as per the protected behavior which is When a method is protected, it can only be accessed by the class itself, subclasses of the class, or classes in the same package as the class . As every class in Java extends from Object, so it should have clone method but still we are forced to override clone. Why is it required? Also, I have read at some places to
订阅 clone