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/*

 * @test

 * @bug 8007574

 * @summary Test Elements.isFunctionalInterface

 * @author  Joseph D. Darcy

 * @library /tools/javac/lib

 * @build   JavacTestingAbstractProcessor TestIsFunctionalInterface

 * @compile -processor TestIsFunctionalInterface TestIsFunctionalInterface.java

 */

import java.util.Set;

import javax.annotation.processing.*;

import javax.lang.model.SourceVersion;

import static javax.lang.model.SourceVersion.*;

import javax.lang.model.element.*;

import javax.lang.model.util.*;

import static javax.lang.model.util.ElementFilter.*;

import static javax.tools.Diagnostic.Kind.*;

import static javax.tools.StandardLocation.*;

import java.io.*;

/**

 * Test basic workings of Elements.isFunctionalInterface

 */

public class TestIsFunctionalInterface extends JavacTestingAbstractProcessor {

    private int count = 0;

    public boolean process(Set<? extends TypeElement> annotations,

                           RoundEnvironment roundEnv) {

        if (!roundEnv.processingOver()) {

            for(TypeElement type : typesIn(roundEnv.getElementsAnnotatedWith(ExpectedIsFunInt.class))) {

                count++;

                System.out.println(type);

                if (elements.isFunctionalInterface(type) !=

                    type.getAnnotation(ExpectedIsFunInt.class).value()) {

                    messager.printMessage(ERROR,

                                          "Mismatch between expected and computed isFunctionalInterface",

                                          type);

                }

            }

        } else {

            if (count <= 0)

                messager.printMessage(ERROR, "No types with ExpectedIsFunInt processed.");

            }

    return true;

    }

}

@interface ExpectedIsFunInt {

    boolean value();

}

// Examples below from the lambda specification documents.

@ExpectedIsFunInt(false) // Equals is already an implicit member

interface Foo1 { boolean equals(Object obj); }

@ExpectedIsFunInt(true) // Bar has one abstract non-Object method

interface Bar1 extends Foo1 { int compare(String o1, String o2); }

@ExpectedIsFunInt(true) // Comparator has one abstract non-Object method

interface LocalComparator<T> {

 boolean equals(Object obj);

 int compare(T o1, T o2);

}

@ExpectedIsFunInt(false) // Method Object.clone is not public

interface Foo2 {

  int m();

  Object clone();

}

interface X1 { int m(Iterable<String> arg); }

interface Y1 { int m(Iterable<String> arg); }

@ExpectedIsFunInt(true) // Two methods, but they have the same signature

interface Z1 extends X1, Y1 {}

interface X2 { Iterable m(Iterable<String> arg); }

interface Y2 { Iterable<String> m(Iterable arg); }

@ExpectedIsFunInt(true) // Y.m is a subsignature & return-type-substitutable

interface Z2 extends X2, Y2 {}

interface Action<T> {

    T doit();

}

@ExpectedIsFunInt(true)

interface LocalExecutor { <T> T execute(Action<T> a); }

interface X5 { <T> T execute(Action<T> a); }

interface Y5 { <S> S execute(Action<S> a); }

@ExpectedIsFunInt(true) // Functional: signatures are "the same"

interface Exec5 extends X5, Y5 {}