I wanted to check Java 8 integration with Eclipse Luna so I downloaded the M7 Luna from eclipse.org.
After configuring the JDK to jdk8u5, I started some tests.
Let's say you have a nice Runnable like
Runnable r = new Runnable() {
#Override
public void run() {
System.out.println("foo");
}
};
If you select the
new Runnable() {
#Override
public void run() {
System.out.println("foo");
}
}
block and press Ctrl-1 (Quick Fix), you get the suggestion to change it to a lambda, resulting in Runnable r = () -> System.out.println("foo");, which is pretty cool.
But a nicer thing whould be to actually help creating lambda expression.
For instance, if you type Runnable r = | (with | being the cursor location) and press ctrl+Space (content-assist), I would have expected to find a "create a lambda expression from this functional interface" option in the displayed popup. But nothing new is available.
Do you know if this will be implemented in the future ?
I think it might have something to do with the templates (Java/Editor/Templates in preferences) but I actually never experimented with them.
Providing good proposal right after the = is rather tricky as almost everything could be placed on the right hand side of an assignment.
Even the old way of implementing a function using an anonymous inner class was not proposed right after the equal sign. You had to type the four characters new␣ before the suggestion came up. And four characters is exactly what you have to type to create a lambda, ()->, but at this place proposing the creation of a lambda makes no sense anymore as you have already created it.
So proposing a lambda would require lifting its priority compared to other proposals to appear right after the equal sign but it would still have rather limited benefit. You had to press crtl+space unless you use automatic menu popup, then select “create lambda” to just get either the four characters ()-> or something like name-> inserted whereas the parameter name(s) are likely to be changed after the proposal is inserted.
For an inner class, read method overriding, it makes sense to propose parameters as you have to repeat all parameter types exactly, but for a lambda where you can omit all the bulk the saving is very limited.
So I don’t expect a proposal of lambda creation to ever appear in the list.
Related
In Spring Tool Suite
(Version: 3.7.0.RELEASE
Build Id: 201506290649
Platform: Eclipse Luna SR2 (4.4.2))
Is there a shortcut to go from something like:
Function<String, Integer> func = str -> Integer.valueOf(str);
to something like this:
Function<String, Integer> func = Integer::valueOf;
(and backwards) via a keyboard shortcut?
I am aware of Ctrl+1 key combo, but it doesn't seem to offer the method reference conversion, hence this inquiry:
First, you need Eclipse 4.5 or greater, because that's when this particular assist was first published.
Next you should avoid the "unused" warning on the variable, because otherwise content assist will jump to the nearest warning / error rather than proposing a change unrelated to any problem in the current code (this is not strictly necessary, but makes the next step easier).
Finally, you need to position the cursor on the ->, because that's the only piece of syntax definitely identifying the lambda.
See also the first item in the 4.5 "New-&-Noteworthy", Section on JDT.
Select the lambda expression "str -> Integer.valueOf(str)" and press Ctrl-1. The first entry in the quick-fix list should be something like "convert to method reference".
Eclipse (any version AFAIK) has some weird behavior related to folding in Java code. Suppose I’m editing this class:
class A {
String field;
#Nonnull
Object method(){
// whatever
}
}
If folding is enabled and I tell it to collapse everything (it’s Control-NumSlash in mine, but that might be customized), the method is correctly folded, i.e. it shows only Object method()... for the method. All good ’till now.
The part that bothers me is that if I move the cursor right after field;, press Enter, and type something like “public”, and then stop for a second, Eclipse automatically folds that word into the method below.
That might seem reasonable (presumably it assumes I wanted to add that qualifier to the method); but in practice what I’m actually doing is trying to add a new method, and paused for a moment to think about its return type or maybe its name. (If I wanted to modify the method I’d unfold it first, since it might already have that qualifier, folded.)
I hate this “feature” with passion, but I can’t for the life of me find out how to disable it, nor even which of the damned mess of plugins (that Eclipse keeps insisting I should not be allowed to remove) is responsible for it so I can file a bug report.
So, does anyone know (1) where does that behavior come from, and hopefully (2) how can I get rid of it but keep manual folding? Thanks!
(For the record, I’m using Kepler SR1, but this behavior goes back a really long time, at least five years or so.)
I don't believe there's any way to prevent it from doing that unless you just make a habit of putting a semicolon ; or closing curly brace } after public which prevents the Object method(){.. from 'folding' it up. I believe it's written to fold everything up until the closest semicolon which is why #Nonnull is also included.
The only options for folding I can find are located in Window > Preferences > Java > Editor > folding
I would consider this to be a bug, or just a feature that had unintended side effects.
Funny enough, if you put almost any symbol or misspell public it wont fold it.
Currently I get this result with Eclipse auto completion.
System.console().printf(format, args)
Of course, Eclipse shows the parameter types as popup, but I want the types to be displayed in front of parameter names too. Like this.
System.console().printf(String format, Object ... args) // `String`, `Object` inserted automatically.
Can I configure Eclipse to show the parameter types too?
Of course not. Eclipse auto completion only suggests valid syntax, while your demand is not valid java code.
An alternative for you might be to open the "Declaration" view or the "JavaDoc" view. Both will always show the declaration/JavaDoc of the currently selected element while you are typing. Therefore you could see the method declaration/javadoc when writing that method call.
Update
Whoever came across this old question. You can use eclipse code mining now:
parameter name hint for Eclipse
At work we're currently using an IDE called PHPEdit, however we're looking to move to another primary IDE, we've been looking at Aptana Studio 3 based off eclipse.
A very nice feature of PHPedit was you could create new methods by clicking a little tool tip under new methods.
For example you could type
$data = $this->model->getData();
and if the function getData() didn't exist you could click the word "getData" and get a little option to create the method, then it would automatically create it in the relevant model and if you passed any params through it like $var, $var, then it would auto set them up as well.
I was wondering if such feature is available or if anybody knows of one as I'm not overly sure what to be searching for in any documentation as I don't know what this is actually called.
Many thanks!
AFAIK eclipse PDT does not have exactly what you want.
You can have a look at Linux programming editors and meybe even checkout Jetbrains
While you are at it, have a look at this question
Eclipse already does that.
I just typed following code in my open editor.
Intent intent = new Intent()
// some code to init intent
String data = getData(intent);
And of course it cried that getData() does not exist. When hovered with mouse, it gives options to create getData(Intent). And when I choose to create this method, it gives following:
protected String getData(Intent intent) {
// TODO Auto-generated method stub
return null;
}
While typing in Eclipse (Java) I often have the problem that when I begin to type accessors, the caret jumps down to the beginning of the constructor definition. So in a document like this:
private int mSomeInt;
public
in|public MyClass(){
}
I would like to manually type out the accessor (getter/setter) for mSomeInt, but when I press space after 'public' above, the caret jumps to the beginning of 'public MyClass'.
I often type complete lines to look up and find my methods jumbled with the constructor (like above).
Any help would be appreciated.
Note - this isn't only with accessors but rather any access modifiers that I define before the constructor or another method.
Edit
After unsuccessfully trying Deco's solution below, I've managed to narrow it down a little further.
The problem only happens if I have all the blocks in the file in a collapsed state (ctrl+shift+numPadDivide). I can see the problem is now that the new access modifier I type is then (quickly) collapsed into the below method. i.e. Eclipse is actually taking the first accessor modifier and collapsing everything from there, even though my intention is actually to write a new method.
The only solution I've been able to find is to only edit the source with all the 'fold' elements unfolded.
Under Window -> Preferences -> <Language> (e.g. Java) -> Editor there is a Content Assist menu item where you can configure auto completion and caret placement as well as auto-activation of it and the delay it uses.
Edit:
After your update to the original question I was able to successfully replicate this in Eclipse Indigo. When you have all of the code blocks collapsed it looks like Eclipse assumes that the code you are writing needs to be in that block (rather than as a variable declaration). I'm not sure if this is expected behaviour or not - but the only way around it I've found is to edit the code with the main block open, and then close it after the fact - or turn folding off altogether.
From what I can tell there are various folding plugins/addons that you can get for Eclipse which override the default behaviour and might function better? A quick Google search will be able to get you a list of them quickly.
I'd probably also suggest posting this as an issue on the Eclipse support site for their official answer.
Unfortunately this issue still exists for me in the latest Elcipse version (Kepler).
As the issue only occurs when the document is 'folded', the work around this is to either disable folding in the editor - or disable folding on 'Members' from the :
Preferences -> Java -> Editor -> Folding