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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/*
 * @test
 * @bug 8292275
 * @summary Verify specific executables in enums and records have mandated parameters
 * @library /tools/javac/lib
 * @modules java.compiler
 *          jdk.compiler
 * @build   JavacTestingAbstractProcessor ImplicitParametersProcessor
 * @compile -processor ImplicitParametersProcessor -proc:only ImplicitParametersProcessor.java
 */

import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.util.Elements;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

import static javax.lang.model.util.ElementFilter.constructorsIn;
import static javax.lang.model.util.ElementFilter.methodsIn;
import static javax.lang.model.util.ElementFilter.typesIn;

public class ImplicitParametersProcessor extends JavacTestingAbstractProcessor {

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        if (roundEnv.processingOver()) {
            return true;
        }
        boolean hasError = false;
        for (TypeElement typeElement : typesIn(roundEnv.getRootElements())) {
            for (TypeElement innerType : typesIn(typeElement.getEnclosedElements())) {
                System.out.println("Visiting " + innerType);
                ExpectedOrigin[] expectedOrigins = innerType.getAnnotationsByType(ExpectedOrigin.class);
                    hasError |= checkAllExecutables(innerType, Arrays.stream(expectedOrigins)
                            .collect(Collectors.toMap(ExpectedOrigin::method, ExpectedOrigin::origins)));
            }
        }
        if (hasError) {
            throw new IllegalStateException("Wrong element origins found");
        }
        return true;
    }

    boolean checkAllExecutables(TypeElement element, Map<String, Elements.Origin[]> expectations) {
        boolean hasError = false;
        for (ExecutableElement executable : constructorsIn(element.getEnclosedElements())) {
            hasError |= checkExecutable(expectations, executable);
        }
        for (ExecutableElement executable : methodsIn(element.getEnclosedElements())) {
            hasError |= checkExecutable(expectations, executable);
        }
        return hasError;
    }

    private boolean checkExecutable(Map<String, Elements.Origin[]> expectations, ExecutableElement executable) {
        System.out.println("Looking at executable " + executable);
        Elements.Origin[] origins = expectations.get(executable.getSimpleName().toString());
        if (origins == null) {
            System.out.println("ignoring this executable due to missing expectations");
            return false;
        }
        List<? extends VariableElement> parameters = executable.getParameters();
        boolean hasError = false;
        for (int i = 0; i < parameters.size(); i++) {
            VariableElement parameter = parameters.get(i);
            Elements.Origin origin = eltUtils.getOrigin(parameter);
            if (origin != origins[i]) {
                System.err.println("ERROR: Wrong origin for " + executable + ". Expected: " + origins[i] + " but got " + origin + " at index " + i);
                hasError = true;
            }
        }
        return hasError;
    }

    // the valueOf(String) method has one mandated parameter
    @ExpectedOrigin(method = "valueOf", origins = {Elements.Origin.MANDATED})
    enum MyEnum {}

    // the parameters of a compact record constructor are mandated
    @ExpectedOrigin(method = "<init>", origins = {Elements.Origin.MANDATED, Elements.Origin.MANDATED})
    record MyRecord(int a, Object b) {
        MyRecord {}
    }

    @interface ExpectedOrigin {
        String method();
        Elements.Origin[] origins();
    }
}