| /* |
| * Copyright 2016 Federico Tomassetti |
| * |
| * Licensed 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 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.github.javaparser.symbolsolver.logic; |
| |
| import com.github.javaparser.symbolsolver.model.declarations.ReferenceTypeDeclaration; |
| import com.github.javaparser.symbolsolver.model.methods.MethodUsage; |
| import com.github.javaparser.symbolsolver.model.typesystem.Type; |
| |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Parameter; |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.Optional; |
| import java.util.Set; |
| import java.util.stream.Collectors; |
| |
| /** |
| * @author Federico Tomassetti |
| */ |
| public final class FunctionalInterfaceLogic { |
| |
| private FunctionalInterfaceLogic() { |
| // prevent instantiation |
| } |
| |
| /** |
| * Get the functional method defined by the type, if any. |
| */ |
| public static Optional<MethodUsage> getFunctionalMethod(Type type) { |
| if (type.isReferenceType() && type.asReferenceType().getTypeDeclaration().isInterface()) { |
| return getFunctionalMethod(type.asReferenceType().getTypeDeclaration()); |
| } else { |
| return Optional.empty(); |
| } |
| } |
| |
| /** |
| * Get the functional method defined by the type, if any. |
| */ |
| public static Optional<MethodUsage> getFunctionalMethod(ReferenceTypeDeclaration typeDeclaration) { |
| //We need to find all abstract methods |
| Set<MethodUsage> methods = typeDeclaration.getAllMethods().stream() |
| .filter(m -> m.getDeclaration().isAbstract()) |
| // Remove methods inherited by Object: |
| // Consider the case of Comparator which define equals. It would be considered a functional method. |
| .filter(m -> !declaredOnObject(m)) |
| .collect(Collectors.toSet()); |
| |
| if (methods.size() == 1) { |
| return Optional.of(methods.iterator().next()); |
| } else { |
| return Optional.empty(); |
| } |
| } |
| |
| private static String getSignature(Method m) { |
| return String.format("%s(%s)", m.getName(), String.join(", ", Arrays.stream(m.getParameters()).map(p -> toSignature(p)).collect(Collectors.toList()))); |
| } |
| |
| private static String toSignature(Parameter p) { |
| return p.getType().getCanonicalName(); |
| } |
| |
| private static List<String> OBJECT_METHODS_SIGNATURES = Arrays.stream(Object.class.getDeclaredMethods()) |
| .map(method -> getSignature(method)) |
| .collect(Collectors.toList()); |
| |
| private static boolean declaredOnObject(MethodUsage m) { |
| return OBJECT_METHODS_SIGNATURES.contains(m.getDeclaration().getSignature()); |
| } |
| } |