test/langtools/tools/javac/patterns/Annotations.java

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/*
 * @test
 * @bug 8256266 8281238
 * @summary Verify annotations work correctly on binding variables
 * @library /tools/javac/lib
 * @modules java.compiler
 *          jdk.compiler
 *          jdk.jdeps/com.sun.tools.classfile
 * @build JavacTestingAbstractProcessor
 * @compile Annotations.java
 * @compile -processor Annotations -proc:only Annotations.java
 * @run main Annotations
 */

import com.sun.source.tree.InstanceOfTree;
import com.sun.source.util.TreePath;
import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import java.util.Set;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.TypeMirror;

import com.sun.source.tree.BindingPatternTree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreePathScanner;
import com.sun.source.util.Trees;
import com.sun.tools.classfile.*;
import java.io.InputStream;
import java.util.Arrays;

public class Annotations extends JavacTestingAbstractProcessor {
    public static void main(String... args) throws Exception {
        new Annotations().run();
    }

    void run() throws Exception {
        InputStream annotationsClass =
                Annotations.class.getResourceAsStream("Annotations.class");
        ClassFile cf = ClassFile.read(annotationsClass);
        for (Method m : cf.methods) {
            if ("test".equals(cf.constant_pool.getUTF8Value(m.name_index))) {
                Code_attribute codeAttr =
                        (Code_attribute) m.attributes.map.get(Attribute.Code);
                Attribute annoAttr =
                        codeAttr.attributes.map.get(Attribute.RuntimeInvisibleTypeAnnotations);
                RuntimeInvisibleTypeAnnotations_attribute annotations =
                        (RuntimeInvisibleTypeAnnotations_attribute) annoAttr;
                String expected = "[@Annotations$DTA; pos: [LOCAL_VARIABLE, {start_pc = 31, length = 7, index = 1}, pos = -1], " +
                                  "@Annotations$TA; pos: [LOCAL_VARIABLE, {start_pc = 50, length = 7, index = 1}, pos = -1]]";
                String actual = Arrays.toString(annotations.annotations);
                if (!expected.equals(actual)) {
                    throw new AssertionError("Unexpected type annotations: " +
                                              actual);
                }
            }
        }
    }

    private static void test(Object o) {
        if (o instanceof @DA String da) {
            System.err.println(da);
        }
        if (o instanceof @DTA String dta) {
            System.err.println(dta);
        }
        if (o instanceof @TA String ta) {
            System.err.println(ta);
        }
    }

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        Trees trees = Trees.instance(processingEnv);

        for (Element root : roundEnv.getRootElements()) {
            TreePath tp = trees.getPath(root);
            new TreePathScanner<Void, Void>() {
                @Override
                public Void visitInstanceOf(InstanceOfTree node, Void p) {
                    BindingPatternTree bpt = (BindingPatternTree) node.getPattern();
                    VariableTree var = bpt.getVariable();
                    Element varEl = trees.getElement(new TreePath(getCurrentPath(), var));
                    String expectedDeclAnnos;
                    String expectedType;
                    switch (var.getName().toString()) {
                        case "da" -> {
                            expectedDeclAnnos = "@Annotations.DA";
                            expectedType = "java.lang.String";
                        }
                        case "dta" -> {
                            expectedDeclAnnos = "@Annotations.DTA";
                            expectedType = "java.lang.@Annotations.DTA String";
                        }
                        case "ta" -> {
                            expectedDeclAnnos = "";
                            expectedType = "java.lang.@Annotations.TA String";
                        }
                        default -> {
                            throw new AssertionError("Unexpected variable: " + var);
                        }
                    }
                    String declAnnos = varEl.getAnnotationMirrors().toString();
                    if (!expectedDeclAnnos.equals(declAnnos)) {
                        throw new AssertionError("Unexpected modifiers: " + declAnnos +
                                                  " for: " + var.getName());
                    }
                    TypeMirror varType = varEl.asType();
                    String type = varType.toString();
                    if (!expectedType.equals(type)) {
                        throw new AssertionError("Unexpected type: " + type +
                                                  " for: " + var.getName() + " expected " + expectedType);
                    }
                    return super.visitInstanceOf(node, p);
                }
            }.scan(tp.getCompilationUnit(), null);
        }
        return false;
    }

    @Target(ElementType.LOCAL_VARIABLE)
    @interface DA {}
    @Target({ElementType.TYPE_USE, ElementType.LOCAL_VARIABLE})
    @interface DTA {}
    @Target(ElementType.TYPE_USE)
    @interface TA {}
}