groovy.transform.stc.PickAnyArgumentHint Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
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package groovy.transform.stc;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.control.CompilationUnit;
import org.codehaus.groovy.control.SourceUnit;
/**
* Base class for hints which use the type of a parameter of the annotated method as the signature.
* This can optionally use a generic type of the selected parameter as the hint. For example, imagine the following
* method:
* void foo(A firstArg, B secondArg, Closure c) {...}
* If the c closure should be { B it -> ...}, then we can see that the parameter type
* should be picked from the second parameter of the foo method, which is what {@link groovy.transform.stc.PickAnyArgumentHint}
* lets you do.
* Alternatively, the method may look like this:
* void <T> foo(A<T> firstArg, B secondArg, Closure c) {...}
* in which case if you want to express the fact that c should accept a <T> then you can use the
* {@link #genericTypeIndex} value.
*
* This class is extended by several hint providers that make it easier to use as annotation values.
*
* @author Cédric Champeau
* @since 2.3.0
*/
public class PickAnyArgumentHint extends SingleSignatureClosureHint {
private final int parameterIndex;
private final int genericTypeIndex;
/**
* Creates the an argument picker which extracts the type of the first parameter.
*/
public PickAnyArgumentHint() {
this(0,-1);
}
/**
* Creates a picker which will extract the parameterIndex-th parameter type, or its
* genericTypeIndex-th generic type genericTypeIndex is >=0.
* @param parameterIndex the index of the parameter from which to extract the type
* @param genericTypeIndex if >=0, then returns the corresponding generic type instead of the parameter type.
*/
public PickAnyArgumentHint(final int parameterIndex, final int genericTypeIndex) {
this.parameterIndex = parameterIndex;
this.genericTypeIndex = genericTypeIndex;
}
@Override
public ClassNode[] getParameterTypes(final MethodNode node, final String[] options, final SourceUnit sourceUnit, final CompilationUnit unit, final ASTNode usage) {
ClassNode type = node.getParameters()[parameterIndex].getOriginType();
if (genericTypeIndex>=0) {
type = pickGenericType(type, genericTypeIndex);
}
return new ClassNode[]{type};
}
}