com.github.javaparser.resolution.declarations.AssociableToAST Maven / Gradle / Ivy
/*
* Copyright (C) 2007-2010 Júlio Vilmar Gesser.
* Copyright (C) 2011, 2013-2023 The JavaParser Team.
*
* This file is part of JavaParser.
*
* JavaParser can be used either under the terms of
* a) the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* b) the terms of the Apache License
*
* You should have received a copy of both licenses in LICENCE.LGPL and
* LICENCE.APACHE. Please refer to those files for details.
*
* JavaParser is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
package com.github.javaparser.resolution.declarations;
import com.github.javaparser.ast.Node;
import java.util.Optional;
/**
* A declaration that can be potentially associated with an AST node.
*/
public interface AssociableToAST {
/**
* If the declaration is associated to an AST node return it, otherwise it return empty.
* Declaration based on source code have an AST node associated while others don't. Example
* of other declarations are declarations coming from reflection or JARs.
*
* You may wonder how this method is different from the various getWrappedNode.
* The difference is that toAst is present in all Resolved* declarations (such as
* ResolvedAnnotationDeclaration), while getWrappedNode is present
* only on the subclasses of the Resolved* declarations that derive from JP AST nodes (such as
* JavaParserClassDeclaration). Therefore one
* which has a Resolved* declaration need to do a downcast before being able to use getWrappedNode.
*
* Now, this means that toAst could potentially replace getWrappedNode (but not the other way around!).
* However toAst return an Optional, which is less convenient than getting the direct node. Also,
* toAst sometimes have to return a more generic node. This is the case for subclasses of
* ResolvedClassDeclaration. In those cases toAst return a Node. Why? Because both anonymous
* class declarations and standard class declarations are subclasses of that. In one case the
* underlying AST node is an ObjectCreationExpr, while in the other case it is ClassOrInterfaceDeclaration.
* In these cases getWrappedNode is particularly nice because it returns the right type of AST node,
* not just a Node.
*/
default Optional toAst() {
return Optional.empty();
}
/**
* If the declaration is associated to an AST node and the type matches the expected {@link Class} return it,
* otherwise it returns empty.
*
* @param clazz The expected class of the AST Node.
* @param The expected type of AST Node.
*
* @return The declaration with the expected {@link Class}.
*
* @see AssociableToAST#toAst()
*/
default Optional toAst(Class clazz) {
return toAst()
.filter(clazz::isInstance)
.map(clazz::cast);
}
}