I'm trying to write a upnp/dlna client for videos and I would like to allow the option to sort by title and date.
With Windows7/wmp as the server, I can use "dc:title" or "dc:date" for sorting and it seems to work but testers have told me it doesn't work on other servers. Is there a universal way to know if sorting is allowed and what the sorting criteria should be?
Thanks.
There is a way to query this (but be prepared for broken implementations that lie about their abilities as well). Quoting ContentDirectory service spec (v3):
2.3.3
SortCapabilities
This state variable is a CSV list of property names that the ContentDirectory service can use to sort
Search() or Browse() action results. An empty string indicates that the device does not support any kind of
sorting. A wildcard (“*”) indicates that the device supports sorting using all property names supported by
the ContentDirectory service. The property names returned MUST include the appropriate namespace
prefixes, except for the DIDL-Lite namespace. Properties in the DIDL-Lite namespace MUST always be
returned without the prefix. All property names MUST be fully qualified using the double colon (“::”)
syntax as defined in Section 2.2.20, “property”. For example,
“upnp:foreignMetadata::fmBody::fmURI”
Related
In my current project in Access VBA, I created a window which works like a console and now I am trying to add a possibility to display any public variable. It should work like:
Show_var [variable_name]
So it should be like in the direct window where i can type:
? pVar.variable_A
I found out that using
Application.VBE.ActiveVBProject.VBComponents(11).CodeModule.CountOfLines
I can display the number of lines within a module or form so I thought perhaps I could somehow find the variables there, cycle through them and when the correct one is found, its value can be shown. OFC I could make a Select Case Statement where all variables are included but that is not the way I want to do it because it is complicated and must be changed every time update my public variable list.
There are so many problems that I think you are out of luck. Let me just list some of them:
There is no way to get a list of all variables - that would mean you would need access to the internal symbol table.
As a consequence, you would have to read the code (CodeModule lets you read the code of a module), and write an own parser to fetch all declarations (hopefully you use Option Explicit)
AFAIK, the is no method that can access the content of a variable via it's name.
Even if there would be any such method: What would you do with different data types, arrays and especially with objects.
If a user runs into problems, often it is a runtime error. If you don't handle that errors with some kind of error handler, the only option if a user cannot enter the debugger is to press "End" - which would destroy the content of all variables.
You have to deal with scope of variables, you can have several variables with the same name and you will likely have lots of variables that are out of scope in the moment you want to dump them.
I am trying to create a custom inspection in IntelliJ using structural search. The idea is to find all methods that have one or more parameters, of which at least one is not annotated. Bonus: Only hit non-primitive types of parameters.
So far, I have created the following Search Template:
$MethodType$ $Method$(#$ParamAnnotation$ $ParameterType$ $Parameter$);
using these filters and the search target "complete match":
$Parameters$: count[1,∞]
$ParamAnnotation$: count[0,0]
However, this only hits methods without any parameters annotated. I want it to also match methods where only some parameters have an annotation but others don't.
Is it possible to reference the count of one variable in the filter of another, e.g. by using script filters? If so, how?
You can do this by creating a Search Template like this:
$MethodType$ $Method$($TypeBefore$ $before$,
#$ParamAnnotation$ $ParameterType$ $Parameter$,
$TypeAfter$ $after$);
Filters:
$Parameters$: count=[1,1] // i.e. no filter
$ParamAnnotation$: count=[0,0]
$before$: count=[0,∞]
$after$: count=[0,∞]
This will find all method with at least one parameter without annotation.
I have a question about preferences.
I have used and seen used both of these examples and was wondering if one is better/faster/preferred over the other...
Using SQL Server 2008
(RS = RecordSet)
RS!field
vs
RS.Fields("Field")
The first is shorter, quicker to type, but is there any advantage to one or the other?
No, they are equivalent in VB. From the documentation:
Use the ! operator only on a class or interface as a dictionary access operator. The class or interface must have a default property that accepts a single String argument. The identifier immediately following the ! operator becomes the argument value passed to the default property as a string.
Since Fields is the "default" property for Recordset and Item is the default property for Fields,
RS!field
is compiled to
RS.Fields("field")
which is technically
RS.Fields.Item("field")
Note that you can also do
RS("field")
is one better/faster/preferred over the other?
Faster? No. Preferred? Well the latter usage is more consistent with other .NET languages, so it may be preferred in larger circles because of that.
I have been using different forms of Mule's Expression language.
I couldn't figure out the difference between
#[flowVars.myVariable]
and
#[flowVars['myVariable']]
They both give the result when there is a variable. But why do they behave differently when the variable is not present?
Like if the variable being called is not available, then the first expression would result in a exception. Whereas the second expression just gives out a warning or prints out as is, if in a logger message.
Why is this difference?
Also when going through the documentation for Mule 3.6 I found that the second expression is not longer shown in the documentation.
Is the expression #[flowVars['myVariable']] being deprecated?
The difference comes from the way MVEL deals with these two different ways of accessing map entries.
#[flowVars['myVariable']] is equivalent to flowVars.get('myVariable'), which does not fail if the flowVars map does not contain the 'myVariable' entry,
#[flowVars.myVariable] treats the flowVars map as a virtual object, leading to an exception if the 'myVariable' entry is missing because in this case it doesn't resolve to a map get but instead to directly using an object member (either a field or a method), which must exist before being accessed.
I don't think #[flowVars['myVariable']] could be deprecated since it's a core feature provided by MVEL.
Reference: http://mvel.codehaus.org/MVEL+2.0+Property+Navigation#MVEL2.0PropertyNavigation-MapAccess
David has given a nice explanation around your question. To extend that explanation I would just like to add that you can use #[flowVars.?myVariable] to make your code null safe. This is equivalent to #[flowVars['myVariable']].
Regarding #[header:originalFilename], as David said this is not MEL. You can get a list of non-mel expressions which are commonly used in Mule applications in the following link.
http://www.mulesoft.org/documentation/display/current/Non-MEL+Expressions+Configuration+Reference
Inside an Objective-C method, it is possible to get the selector of the method with the keyword _cmd. Does such a thing exist for the names of arguments?
For example, if I have a method declared as such:
- (void)methodWithAnArgument:(id)foo {
...
}
Is there some sort of construct that would allow me to get access to some sort of string-like representation of the variable name? That is, not the value of foo, but something that actually reflects the variable name "foo" in a local variable inside the method.
This information doesn't appear to be stored in NSInvocation or any of its related classes (NSMethodSignature, etc), so I'm not optimistic this can be done using Apple's frameworks or the runtime. I suspect it might be possible with some sort of compile-time macro, but I'm unfamiliar with C macros so I wouldn't know where to begin.
Edit to contain more information about what I'm actually trying to do.
I'm building a tool to help make working with third-party URL schemes easier. There are two sides to how I want my API to look:
As a consumer of a URL scheme, I can call a method like [twitterHandler showUserWithScreenName:#"someTwitterHandle"];
As a creator of an app with a URL scheme, I can define my URLs in a plist dictionary, whose key-value pairs look something like #"showUserWithScreenName": #"twitter://user?screenName={screenName}".
What I'm working on now is finding the best way to glue these together. The current fully-functioning implementation of showUserWithScreenName: looks something like this:
- (void)showUserWithScreenName:(NSString *)screenName {
[self performCommand:NSStringFromSelector(_cmd) withArguments:#{#"screenName": screenName}];
}
Where performCommand:withArguments: is a method that (besides some other logic) looks up the command key in the plist (in this case "showUserWithScreenName:") and evaluates the value as a template using the passed dictionary as the values to bind.
The problem I'm trying to solve: there are dozens of methods like this that look exactly the same, but just swap out the dictionary definition to contain the correct template params. In every case, the desired dictionary key is the name of the parameter. I'm trying to find a way to minimize my boilerplate.
In practice, I assume I'm going to accept that there will be some boilerplate needed, but I can probably make it ever-so-slightly cleaner thanks to NSDictionaryOfVariableBindings (thanks #CodaFi — I wasn't familiar with that macro!). For the sake of argument, I'm curious if it would be possible to completely metaprogram this using something like forwardInvocation:, which as far as I can tell would require some way to access parameter names.
You can use componentsSeparatedByString: with a : after you get the string from NSStringFromSelector(_cmd) and use your #selector's argument names to put the arguments in the correct order.
You can also take a look at this post, which is describing the method naming conventions in Objective C