Warn when certain constructor is used (original) (raw)

Eddie Aftandilian eaftan at google.com
Thu May 31 16:59:03 UTC 2018

Forgive the self promotion, but you could use Error Prone ( github.com/google/error-prone). Just write a BugChecker that implements NewClassTreeMatcher, match on the constructor you want, and emit a warning when it matches. Here's an example similar to what you want to do: https://github.com/google/error-prone/blob/d6574253e5cff136662c4fd2ace6ba1c5ae831fa/core/src/main/java/com/google/errorprone/bugpatterns/StringBuilderInitWithChar.java

On Thu, May 31, 2018 at 7:45 AM Maurizio Cimadamore < maurizio.cimadamore at oracle.com> wrote:

Try to call

https://docs.oracle.com/javase/7/docs/jdk/api/javac/tree/com/sun/source/util/Trees.html#getElement(com.sun.source.util.TreePath) This should trigger attribution of the tree and give you the 'symbol' associated with the constructor. From there you can access the symbol signature using https://docs.oracle.com/javase/7/docs/api/javax/lang/model/element/Element.html#asType() And downcasting to this: https://docs.oracle.com/javase/7/docs/api/javax/lang/model/type/ExecutableType.html If this works, good, otherwise the solution would be more cumbersome - and it will involve setting up a task listener. But try this first. Maurizio On 31/05/18 13:19, Pietro Paolini wrote: > Hi Maurizio, > > Thanks a lot. I would have an additional, and hopefully last, question. > > I am getting the NewClassTree which seems to provide me access to the - forgive me the coarse wording of it - the "token", namely the textual representation > of it, while I am mainly interested in the type. > > I am getting around it by comparing strings but I wonder if there is any way to get to the type of the expression : > > := new identifier ( arguments ) > > What I have in my mind is to detect all instances in which the identifier has type A and the argument's list is composed by a single type , let say B. That allows me to > print something: > > "Hey, constructor new A(B) has been detected" > > Thanks a lot for your help so far, really. > > Thanks, > P. > > > > > >> -----Original Message----- >> From: Maurizio Cimadamore [mailto:maurizio.cimadamore at oracle.com] >> Sent: 31 May 2018 12:45 >> To: Pietro Paolini >> Cc: compiler-dev at openjdk.java.net >> Subject: Re: Warn when certain constructor is used >> >> >> >> On 31/05/18 12:21, Pietro Paolini wrote: >>> JCTree tree = (JCTree) trees.getTree(element); >>> tree.accept(new LocalDateUtilDate()); >> There re two visitor methods in JCTree, one internal (used by javac), >> one external (used by the API). I don't think you need to cast down to >> JCTree (yet, at least). Just keep it as a com.sun.source.tree.Tree, and >> you will see that the only 'accept' method there takes two arguments: a >> visitor (which you have) and a visitor parameter; since you don't seem >> to need a visitor parameter, you can just pass 'null' as second parameter. >> >> Maurizio -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.openjdk.java.net/pipermail/compiler-dev/attachments/20180531/062d418c/attachment.html>

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