I have the following code:
private void Example(Func<string,int> myDelegate)
{
int length = myDelegate(RECEIVEDSTRING).; //How to access received string??
}
When I execute the method : Example(x=>"Hello".Length); How can I access to the string "Hello" inside the method Example?
Thanks.
Regards.
Jose.
That is not how you should be processing this delegate. It takes an input parameter and Example needs to know some details about the input parameter in order to execute the delegate. Here Example "acts" as an interface to external code and that external code MUST provide their own implementation.
If Example needs to execute the delegate then it needs to provide the REQUIRED string parameter. IMHO, Example needs to provide a second parameter in its signature as below...
private void Example(string s, Func<string,int> myDelegate)
{
int length = myDelegate(s);
}
Then external code can provide is own implementation and parameter...
Example("Hello", x => { return x.Length; });
What you are trying to do is not possible in C#, the delegate needs to an explicit context to run, that context is the string input parameter.
Hope it makes sense
Related
I have a rule that looks like this:
INTEGER : [0-9]+;
myFields : uno=INTEGER COMMA dos=INTEGER
Right now to access uno I need to code:
Integer i = Integer.parseInt(myFields.uno.getText())
It would be much cleaner if I could tell antler to do that conversion for me; then I would just need to code:
Integer i = myFields.uno
What are my options?
You could write the code as action, but it would still be explicit conversion (eventually). The parser (like every parser) parses the text and then it's up to "parsing events" (achieved by listener or visitor or actions in ANTLR4) to create meaningful structures/objects.
Of course you could extend some of the generated or built-in classes and then get the type directly, but as mentioned before, at some point you'll always need to convert text to some type needed.
A standard way of handling custom operations on tokens is to embed them in a custom token class:
public class MyToken extends CommonToken {
....
public Integer getInt() {
return Integer.parseInt(getText()); // TODO: error handling
}
}
Also create
public class MyTokenFactory extends TokenFactory { .... }
to source the custom tokens. Add the factory to the lexer using Lexer#setTokenFactory().
Within the custom TokenFactory, override the method
Symbol create(int type, String text); // (typically override both factory methods)
to construct and return a new MyToken.
Given that the signature includes the target token type type, custom type-specific token subclasses could be returned, each with their own custom methods.
Couple of issues with this, though. First, in practice, it is not typically needed: the assignment var is statically typed, so as in the the OP example,
options { TokenLabelType = "MyToken"; }
Integer i = myFields.uno.getInt(); // no cast required
If Integer is desired & expected, use getInt(). If Boolean ....
Second, ANTLR options allows setting a TokenLabelType to preclude the requirement to manually cast custom tokens. Use of only one token label type is supported. So, to use multiple token types, manual casting is required.
hi does anyone encountered this error? everytime I use PXSelect on a foreach loop in which on the other source code does but on my code does not, could anyone identify the cause? the code below is also the the original source code from Acumatica but I only changed the Datamember from PaymentCharges to OtherCharges
[PXOverride]
public void VoidCheckProc(ARPayment doc)
{
foreach (PXResult<ARPaymentChargeTran> paycharge in PXSelect<ARPaymentChargeTran, Where<ARPaymentChargeTran.docType, Equal<Required<ARPayment.docType>>, And<ARPaymentChargeTran.refNbr, Equal<Required<ARPayment.refNbr>>>>>.
Select(this, doc.DocType, doc.RefNbr))
{
ARPaymentChargeTran charge = PXCache<ARPaymentChargeTran>.CreateCopy((ARPaymentChargeTran)paycharge);
charge.DocType = Document.Current.DocType;
charge.CuryTranAmt = -1 * charge.CuryTranAmt;
charge.Released = false;
charge.CuryInfoID = Document.Current.CuryInfoID;
charge.CashTranID = null;
//PaymentCharges.Insert(charge);
OtherCharges.Insert(charge);
}
}
I believe, you are writing this method in an extension for the base BLC
So instead of using 'this', use 'this.Base'
The Select method is non-static, as the error message says, but you call it on the PXSelect<...>-type. You need to have an instance of that type.
Based on Hybridzz answer, I assume you used the wrong overload of the Select-method. Probably your arguments do not have the correct type, so the compiler selects the best fitting overload of the method. In this case, it selects the one accepting only the argument params object[] o, which is non-static. A bit misleasing design of the API you use.
For a parameter class
class Criteria {
private Map params;
public getMap(){ return params; }
}
and a service method accept this criteria
class Service{
public List<Person> query(Criteria criteria){ ... }
}
A custom featureMatcher is used to match the criteria key
private Matcher<Criteria> hasCriteria(final String key, final Matcher<?> valueMatcher){
return new FeatureMatcher<Criteria, Object>((Matcher<? super Object>)valueMatcher, key, key){
#Override protected Object featureValueOf(Criteria actual){
return actual.getMap().get(key);
}
}
}
when using mockito to veryify the arguments:
verify(Service).query((Criteria) argThat("id", hasCriteria("id", equalTo(new Long(12)))));
The error message shows that:
Argument(s) are different! Wanted:
Service.query(
id <12L>
);
-> at app.TestTarget.test_id (TestTarget.java:134)
Actual invocation has different arguments:
Service.query(
app.Criteria#509f5011
);
If I use ArugmentCaptor,
ArgumentCaptor<Criteria> argument = ArgumentCaptor.forClass(Criteria.class);
verify(Service).query(argument.capture());
assertThat(argument.getValue(), hasCriteria("id", equalTo(new Long(12))));
The message is much better:
Expected: id <12L> but id was <2L>
How can I get such message, without using ArgumentCaptor?
The short answer is to adjust the Criteria code, if it's under your control, to write a better toString method. Otherwise, you may be better off using the ArgumentCaptor method.
Why is it hard to do without ArgumentCaptor? You know you're expecting one call, but Mockito was designed to handle it even if you have a dozen similar calls to evaluate. Even though you're using the same matcher implementation, with the same helpful describeMismatch implementation, assertThat inherently tries once to match where verify sees a mismatch and keeps trying to match any other call.
Consider this:
// in code:
dependency.call(true, false);
dependency.call(false, true);
dependency.call(false, false);
// in test:
verify(mockDependency).call(
argThat(is(equalTo(true))),
argThat(is(equalTo(true))));
Here, Mockito wouldn't know which of the calls was supposed to be call(true, true); any of the three might have been it. Instead, it only knows that there was a verification you were expecting that was never satisfied, and that one of three related calls might have been close. In your code with ArgumentCaptor, you can use your knowledge that there's only one call, and provide a more-sane error message; for Mockito, the best it can do is to output all the calls it DID receive, and without a helpful toString output for your Criteria, that's not very helpful at all.
I have the current method example:
public void MethodName(string param1,int param2)
{
object[] obj = new object[] { (object) param1, (object) param2 };
//Code to that uses this array to invoke dynamic methods
}
Is there a dynamic way (I am guessing using reflection) that will get the current executing method parameter values and place them in a object array? I have read that you can get parameter information using MethodBase and MethodInfo but those only have information about the parameter and not the value it self which is what I need.
So for example if I pass "test" and 1 as method parameters without coding for the specific parameters can I get a object array with two indexes { "test", 1 }?
I would really like to not have to use a third party API, but if it has source code for that API then I will accept that as an answer as long as its not a huge API and there is no simple way to do it without this API.
I am sure there must be a way, maybe using the stack, who knows. You guys are the experts and that is why I come here.
Thank you in advance, I can't wait to see how this is done.
EDIT
It may not be clear so here some extra information. This code example is just that, an example to show what I want. It would be to bloated and big to show the actual code where it is needed but the question is how to get the array without manually creating one. I need to some how get the values and place them in a array without coding the specific parameters.
Using reflection you can extract the parameters name and metadata but not the actual values :
class Program
{
static void Main(string[] args)
{
Program p = new Program();
p.testMethod("abcd", 1);
Console.ReadLine();
}
public void testMethod(string a, int b)
{
System.Diagnostics.StackTrace st = new System.Diagnostics.StackTrace();
StackFrame sf = st.GetFrame(0);
ParameterInfo[] pis = sf.GetMethod().GetParameters();
foreach (ParameterInfo pi in pis)
{
Console.Out.WriteLine(pi.Name);
}
}
}
Using C# 4.0 features I want a generic wrapper for encapsulating functions and add a TimeOut parameter to them.
For example we have a function like:
T DoLengthyOperation()
Using Func we have:
Func<T>
This is good and call the function even Sync (Invloke) or Async(BeginInvoke).
Now think of a TimeOut to be added to this behavior and if DoLengthyOperation() returns in specified time we have true returned, otherwise false.
Something like:
FuncTimeOut<in T1, in T2, ..., out TResult, int timeOut, bool result>
Implement C# Generic Timeout
Don't return true/false for complete. Throw an exception.
I don't have time to implement it, but it should be possible and your basic signature would look like this:
T DoLengthyOperation<T>(int TimeoutInMilliseconds, Func<T> operation)
And you could call this method either by passing in the name of any Func<T> as an argument or define it place as a lambda expression. Unfortunately, you'll also need to provide an overload for different kind of function you want, as there's currently no way to specify a variable number a generic type arguments.
Instead of mixing out and bool I would instead construct a separate type to capture the return. For example
struct Result<T> {
private bool _isSuccess;
private T _value;
public bool IsSucces { get { return _success; } }
public T Value { get { return _value; } }
public Result(T value) {
_value = value;
_isSuccess = true;
}
}
This is definitely possible to write. The only problem is that in order to implement a timeout, it's necessary to do one of the following
Move the long running operation onto another thread.
Add cancellation support to the long running operation and signal cancellation from another thread.
Ingrain the notion of timeout into the operation itself and have it check for the time being expired at many points in the operation.
Which is best for you is hard to determine because we don't know enough about your scenario. My instinct though would be to go for #2 or #3. Having the primary code not have to switch threads is likely the least impactful change to your code.