Class FromAbstractTypeMethods
public class FromAbstractTypeMethods extends ClosureSignatureHint
- Since:
- 2.3.0
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Constructor Summary
Constructors Constructor Description FromAbstractTypeMethods()
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Method Summary
Modifier and Type Method Description java.util.List<ClassNode[]>
getClosureSignatures(MethodNode node, SourceUnit sourceUnit, CompilationUnit compilationUnit, java.lang.String[] options, ASTNode usage)
Subclasses should implement this method, which returns the list of accepted closure signatures.Methods inherited from class groovy.transform.stc.ClosureSignatureHint
findClassNode, pickGenericType, pickGenericType
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Constructor Details
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FromAbstractTypeMethods
public FromAbstractTypeMethods()
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Method Details
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getClosureSignatures
public java.util.List<ClassNode[]> getClosureSignatures(MethodNode node, SourceUnit sourceUnit, CompilationUnit compilationUnit, java.lang.String[] options, ASTNode usage)Description copied from class:ClosureSignatureHint
Subclasses should implement this method, which returns the list of accepted closure signatures.
The compiler will call this method each time, in a source file, a method call using a closure literal is encountered and that the target method has the corresponding
Closure
parameter annotated withClosureParams
. So imagine the following code needs to be compiled:@groovy.transform.TypeChecked void doSomething() { println ['a','b'].collect { it.toUpperCase() } }
The collect method accepts a closure, but normally, the type checker doesn't have enough type information in the sole
DefaultGroovyMethods.collect(java.lang.Iterable, groovy.lang.Closure)
method signature to infer the type of it. With the annotation, it will now try to find an annotation on the closure parameter. If it finds it, then an instance of the hint class is created and the type checker calls it with the following arguments:- the method node corresponding to the target method (here, the
DefaultGroovyMethods.collect(java.lang.Iterable, groovy.lang.Closure)
method - the (optional) list of options found in the annotation
Now, the hint instance can return the list of expected parameters. Here, it would have to say that the collect method accepts a closure for which the only argument is of the type of the first generic type of the first argument.
With that type information, the type checker can now infer that the type of it is String, because the first argument (here the receiver of the collect method) is a List<String>
Subclasses are therefore expected to return the signatures according to the available context, which is only the target method and the potential options.
- Specified by:
getClosureSignatures
in classClosureSignatureHint
- Parameters:
node
- the method node for which aClosure
parameter was annotated withClosureParams
sourceUnit
- the source unit of the file being compiledcompilationUnit
- the compilation unit of the file being compiledoptions
- the options, corresponding to theClosureParams.options()
found on the annotation @return a non-null list of signature, where a signature corresponds to an array of class nodes, each of them matching a parameter.usage
- the AST node, in the compiled file, which triggered a call to this method. Normally only used for logging/error handling
- the method node corresponding to the target method (here, the
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