I recently switched to Java 11 for a rather big project, and would like to switch to using var class = new Class() instead of Class class = new CLass().
I tried using Intellij Structural Search (and replace) for this, but its turning out to be more complex than expected.
My first attempt was $Type$ $Inst$ = new $Constructor$($Argument$);, which also matches global variables (which don't allow var).
My second attempt is:
class $Class$ {
$ReturnType$ $Method$ ($ParameterType$ $Parameter$) throws $ExceptionType$ {
$Statements$;
final $Type$ $Inst$ = new $Constructor$($Argument$);
$Statements2$;
}
}
Which misses all calls inside e.g. try blocks (since they get matched by the expressions)
Any help would be greatly appreciated!
Use your first template
$Type$ $Inst$ = new $Constructor$($Argument$);
But add a Script modifier on the $Inst$ variable with the following text:
Inst instanceof com.intellij.psi.PsiLocalVariable
Alternatively you may want to try the Local variable type can be omitted inspection that is available in IntelliJ IDEA.
Related
Is there a way to set the context of the expression in Dynamic Expresso library, so that we can do something like the following:
interpreter.Eval("FirstName", new Parameter("person", new { FirstName="Homer", LastName="Simpson"}));
rather than
interpreter.Eval("person.FirstName", new Parameter("person", new { FirstName="Homer", LastName="Simpson"}));
Maybe we could have a another option that would say that the first parameter is to be used as the context for the expression.
I guess there could also be another version of Parse and Eval methods that simply takes the expression text and a simple object value that will serve as the expression context.
Other than that and the lack of support for dynamic types, I am really liking this library. I had worked on something similar, but had not added support for extension methods and generic method calls.
Thanks for the great library,
Neal
There isn't a built-in solution but you can simulate it in many ways:
Option 1: Inject an expression
var workingContext = new { FirstName = "homer" };
var workingContextExpression = Expression.Constant(workingContext);
var firstNameExpression = Expression.Property(workingContextExpression, "FirstName");
var interpreter = new Interpreter();
interpreter.SetExpression("FirstName", firstNameExpression);
Assert.AreEqual(workingContext.FirstName, interpreter.Eval("FirstName"));
Basically I inject an expression using SetExpression method. The injected expression is the property that you want to be available.
Option 2: Use this/me/it variable
You can inject a variable that will contain your working object. I usually call it this (or me or it depending on the application).
var workingContext = new { FirstName = "homer" };
var interpreter = new Interpreter();
interpreter.SetVariable("this", workingContext);
Assert.AreEqual(workingContext.FirstName, interpreter.Eval("this.FirstName"));
Option 3: A combination of the previous solutions
var workingContext = new { FirstName = "homer" };
var interpreter = new Interpreter();
interpreter.SetVariable("this", workingContext);
var firstNameExpression = interpreter.Parse("this.FirstName").LambdaExpression.Body;
interpreter.SetExpression("FirstName", firstNameExpression);
Assert.AreEqual(workingContext.FirstName, interpreter.Eval("FirstName"));
Equal to the first solution but I generate the expression using the parser itself.
Consider that all solutions assume that you must have an Interpreter instance for each context.
Disclaimer: I'm the author of Dynamic Expresso library.
Starting with DynamicExpresso v2.13.0, it's possible to define a variable named "this", that will be used for implicit resolution:
var target = new Interpreter();
target.SetVariable("this", new { FirstName="Homer", LastName="Simpson"});
// 'this' variable is used implicitly
Assert.AreEqual("Homer", target.Eval("FirstName"));
// 'this' variable can also be used explicitly
Assert.AreEqual("Homer", target.Eval("this.FirstName"));
Problem
I am facing a problem using dynamically created list of items when Add method is called on dynamicvariable. Consider following code.
IEnumerable<dynamic> plugins = (IEnumerable<dynamic>)field.GetValue(instance);
if (plugins == null)
continue;
dynamic filteredPlugins = null;
foreach (var plugin in plugins)
{
if (filteredPlugins == null)
filteredPlugins = Activator
.CreateInstance(typeof(List<>)
.MakeGenericType(plugin.GetType()));
if (/* this condition does not matter*/)
//filteredPlugins.Add(plugin);
filteredPlugins.GetType().GetMethod("Add")
.Invoke(filteredPlugins, new object[] { plugin });
}
And now, the commented line filteredPlugins.Add(plugin) will throw System.Reflection.TargetInvocationException with the message 'object' does not contain a definition for 'Add' when plugin is of type
System.ComponentModel.Composition.ExportServices.DisposableLazy<IPlugin,IMetadata>
but it works completely perfect when pluginis of type
System.Lazy<IPlugin, IMetadata>
When the reflection is used to call Add method on the instance filteredPlugins instance as is done on the next line - everything works fine for any type.
My question is WHY is not Add method found in case of DisposableLazy type.
Background
This code is part of the method that I use in OnImportsSatisfied() method. I am using two kinds of import - which differs only in RequiredCreationPolicy - on has CreationPolicy.NonShared and the other default value of CreationPolicy.Any.
[ImportMany(RequiredCreationPolicy = CreationPolicy.NonShared)]
private IEnumerable<Lazy<IPlugin, IMetadata>> plugins = null;
For CreationPolicy.NonShared fields the underlaying type in the plugins is DisposableLazy and for CreationPolicy.Any the underlaying type in the plugins is Lazy.
Edit: As asked in the answer - I am using dynamic variable because IPlugin interface can change everytime this method is called and they do not have to have anything in common.
Edit2: I just found similar question C# dynamic type gotcha, so this can be probably closed as duplicite.
Because System.ComponentModel.Composition.ExportServices.DisposableLazy is a private class, the runtime binder is having trouble believing you have permission to use type, where reflection doesn't care.
Which begs the question why are you using dynamics at all in this case. Since DisposableLazy<IPlugin,IMetadata> public interface is it's subclass Lazy<IPlugin, IMetadata> & IDisposable, shouldn't you just be using a List<Lazy<IPlugin, IMetadata>> for either case?
var plugins = (IEnumerable<Lazy<IPlugin, IMetadata>>)field.GetValue(instance);
if (plugins == null)
continue;
var filteredPlugins = new List<Lazy<IPlugin, IMetadata>>();
foreach (var plugin in plugins)
{
if (/* this condition does not matter*/)
filteredPlugins.Add(plugin);
}
}
when using a cellbrowser and adding that widget to a flowpanel (to be placed wherever, downstream), for some reason the end result is dead (a blank screen)...vs if I add directly to the rootpanel (or layout panel)
Also had the same problem. I had to use a <g:HTMLPanel> as the parent of the CellBrowser (as seen in the GWT Showcase).
Do you have some sample code that will reproduce this?
below is the code for the composite...essentially, what I'd like to do is in another class, attached this composite to a flowpanel and do whatever with it...but, the reality is, I have to attach is directly to the RootPanel (or RootLayoutPanel)...any other abstraction causes it to bail
for example
FlowPanel fp = new FlowPanel();
V2_M76Rolodex v = new V2_M76Rolodex();
fp.add(v); // not going to work
RootPanel.get.add(v) works
public class V2_M76Rolodex extends Composite {
/*
a bunch of code here for getting data and
populating the tree - works, not at issue or relevant
*/
public V2_M76Rolodex() {
TreeViewModel model = new CustomTreeModel();
CellBrowser browser = new CellBrowser(model, null);
browser.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);
browser.addStyleName("rolodex_cell_browser");
initWidget(browser);
}
}
In my app, I use Groovy as a scripting language. To make things easier for my customers, I have a global scope where I define helper classes and constants.
Currently, I need to run the script (which builds the global scope) every time a user script is executed:
context = setupGroovy();
runScript( context, "global.groovy" ); // Can I avoid doing this step every time?
runScript( context, "user.groovy" );
Is there a way to setup this global scope once and just tell the embedded script interpreter: "Look here if you can't find a variable"? That way, I could run the global script once.
Note: Security is not an issue here but if you know a way to make sure the user can't modify the global scope, that's an additional plus.
Shamelessly stolen from groovy.codehaus :
The most complete solution for people
who want to embed groovy scripts into
their servers and have them reloaded
on modification is the
GroovyScriptEngine. You initialize the
GroovyScriptEngine with a set of
CLASSPATH like roots that can be URLs
or directory names. You can then
execute any Groovy script within those
roots. The GSE will also track
dependencies between scripts so that
if any dependent script is modified
the whole tree will be recompiled and
reloaded.
Additionally, each time you run a
script you can pass in a Binding that
contains properties that the script
can access. Any properties set in the
script will also be available in that
binding after the script has run. Here
is a simple example:
/my/groovy/script/path/hello.groovy:
output = "Hello, ${input}!"
import groovy.lang.Binding;
import groovy.util.GroovyScriptEngine;
String[] roots = new String[] { "/my/groovy/script/path" };
GroovyScriptEngine gse = new GroovyScriptEngine(roots);
Binding binding = new Binding();
binding.setVariable("input", "world");
gse.run("hello.groovy", binding);
System.out.println(binding.getVariable("output"));
This will print "Hello, world!".
Found: here
Would something like that work for you?
A simple solution is to use the code from groovy.lang.GroovyShell: You can precompile the script like so:
GroovyCodeSource gcs = AccessController.doPrivileged( new PrivilegedAction<GroovyCodeSource>() {
public GroovyCodeSource run() {
return new GroovyCodeSource( scriptCode, fileName, GroovyShell.DEFAULT_CODE_BASE );
}
} );
GroovyClassLoader loader = AccessController.doPrivileged( new PrivilegedAction<GroovyClassLoader>() {
public GroovyClassLoader run() {
return new GroovyClassLoader( parentLoader, CompilerConfiguration.DEFAULT );
}
} );
Class<?> scriptClass = loader.parseClass( gcs, false );
That's was the expensive part. Now use InvokeHelper to bind the compiled code to a context (with global variables) and run it:
Binding context = new javax.script.Binding();
Script script = InvokerHelper.createScript(scriptClass, context);
script.run();
I am new Web App development using Flex Builder 3 and currently I am facing the following problem:
Attached is a code snippet from the mxml file:
<mx:Script>
<![CDATA[
import com.bx.Char10;
import com.bx.A;
[Bindable] private var inputParam:A = new A()
inputParam.CustNumber.char10 = '0123456789'
}
]]>
</mx:Script>
This Gives a compile error
1120 Access of undefined property inputParam
However if I replace
inputParam.CustNumber.char10 = '0123456789'
with
private function set():void
{
inputParam.CustNumber.char10 = '0123456789'
}
The compile error goes away.
My Question is :
How can I remove this Compilation Error without using the workaround I did?
Hmm, I don't believe that one can execute arbitrary statements directly inside a class body. (The "Script" tag's contents are treated as if they were directly inside the class body).
Only function definitions or variable property definitions are allowed.
A different work-around to use is to pass the information through the constructor of the variable property you're interested in.
[Bindable] private var inputParam:A = new A('0123456789')