Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.codehaus.groovy.classgen; import org.codehaus.groovy.ast.AnnotatedNode; import org.codehaus.groovy.ast.AnnotationNode; import org.codehaus.groovy.ast.ClassCodeVisitorSupport; import org.codehaus.groovy.ast.ClassHelper; import org.codehaus.groovy.ast.ClassNode; import org.codehaus.groovy.ast.ConstructorNode; import org.codehaus.groovy.ast.FieldNode; import org.codehaus.groovy.ast.MethodNode; import org.codehaus.groovy.ast.PackageNode; import org.codehaus.groovy.ast.Parameter; import org.codehaus.groovy.ast.PropertyNode; import org.codehaus.groovy.ast.expr.AnnotationConstantExpression; import org.codehaus.groovy.ast.expr.ClassExpression; import org.codehaus.groovy.ast.expr.DeclarationExpression; import org.codehaus.groovy.ast.expr.Expression; import org.codehaus.groovy.ast.expr.ListExpression; import org.codehaus.groovy.ast.stmt.ReturnStatement; import org.codehaus.groovy.ast.stmt.Statement; import org.codehaus.groovy.ast.tools.ParameterUtils; import org.codehaus.groovy.control.AnnotationConstantsVisitor; import org.codehaus.groovy.control.CompilerConfiguration; import org.codehaus.groovy.control.ErrorCollector; import org.codehaus.groovy.control.SourceUnit; import org.objectweb.asm.Opcodes; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.stream.Collectors; import static org.codehaus.groovy.ast.tools.GenericsUtils.correctToGenericsSpec; import static org.codehaus.groovy.ast.tools.GenericsUtils.correctToGenericsSpecRecurse; import static org.codehaus.groovy.ast.tools.GenericsUtils.createGenericsSpec; import static org.codehaus.groovy.transform.stc.StaticTypeCheckingSupport.evaluateExpression; /** * A specialized Groovy AST visitor meant to perform additional verifications upon the * current AST. Currently it does checks on annotated nodes and annotations itself. * <p> * Current limitations: * - annotations on local variables are not supported */ public class ExtendedVerifier extends ClassCodeVisitorSupport { public static final String JVM_ERROR_MESSAGE = "Please make sure you are running on a JVM >= 1.5"; private final SourceUnit source; private ClassNode currentClass; public ExtendedVerifier(SourceUnit sourceUnit) { this.source = sourceUnit; } @Override protected SourceUnit getSourceUnit() { return this.source; } @Override public void visitClass(ClassNode node) { AnnotationConstantsVisitor acv = new AnnotationConstantsVisitor(); acv.visitClass(node, this.source); this.currentClass = node; if (node.isAnnotationDefinition()) { visitAnnotations(node, AnnotationNode.ANNOTATION_TARGET); } else { visitAnnotations(node, AnnotationNode.TYPE_TARGET); } PackageNode packageNode = node.getPackage(); if (packageNode != null) { visitAnnotations(packageNode, AnnotationNode.PACKAGE_TARGET); } node.visitContents(this); } @Override public void visitField(FieldNode node) { visitAnnotations(node, AnnotationNode.FIELD_TARGET); } @Override public void visitDeclarationExpression(DeclarationExpression expression) { visitAnnotations(expression, AnnotationNode.LOCAL_VARIABLE_TARGET); } @Override public void visitConstructor(ConstructorNode node) { visitConstructorOrMethod(node, AnnotationNode.CONSTRUCTOR_TARGET); } @Override public void visitMethod(MethodNode node) { visitConstructorOrMethod(node, AnnotationNode.METHOD_TARGET); } private void visitConstructorOrMethod(MethodNode node, int methodTarget) { visitAnnotations(node, methodTarget); for (Parameter parameter : node.getParameters()) { visitAnnotations(parameter, AnnotationNode.PARAMETER_TARGET); } if (this.currentClass.isAnnotationDefinition() && !node.isStaticConstructor()) { ErrorCollector errorCollector = new ErrorCollector(this.source.getConfiguration()); AnnotationVisitor visitor = new AnnotationVisitor(this.source, errorCollector); visitor.setReportClass(this.currentClass); visitor.checkReturnType(node.getReturnType(), node); if (node.getParameters().length > 0) { addError("Annotation members may not have parameters.", node.getParameters()[0]); } if (node.getExceptions().length > 0) { addError("Annotation members may not have a throws clause.", node.getExceptions()[0]); } ReturnStatement code = (ReturnStatement) node.getCode(); if (code != null) { visitor.visitExpression(node.getName(), code.getExpression(), node.getReturnType()); visitor.checkCircularReference(this.currentClass, node.getReturnType(), code.getExpression()); } this.source.getErrorCollector().addCollectorContents(errorCollector); } Statement code = node.getCode(); if (code != null) { code.visit(this); } } @Override public void visitProperty(PropertyNode node) { } protected void visitAnnotations(AnnotatedNode node, int target) { if (node.getAnnotations().isEmpty()) { return; } this.currentClass.setAnnotated(true); if (!isAnnotationCompatible()) { addError("Annotations are not supported in the current runtime. " + JVM_ERROR_MESSAGE, node); return; } Map<String, List<AnnotationNode>> nonSourceAnnotations = new LinkedHashMap<>(); for (AnnotationNode unvisited : node.getAnnotations()) { AnnotationNode visited; { ErrorCollector errorCollector = new ErrorCollector(source.getConfiguration()); AnnotationVisitor visitor = new AnnotationVisitor(source, errorCollector); visited = visitor.visit(unvisited); source.getErrorCollector().addCollectorContents(errorCollector); } String name = visited.getClassNode().getName(); if (!visited.hasSourceRetention()) { List<AnnotationNode> seen = nonSourceAnnotations.get(name); if (seen == null) { seen = new ArrayList<>(); } seen.add(visited); nonSourceAnnotations.put(name, seen); } // Check if the annotation target is correct, unless it's the target annotating an annotation definition // defining on which target elements the annotation applies boolean isTargetAnnotation = name.equals("java.lang.annotation.Target"); if (!isTargetAnnotation && !visited.isTargetAllowed(target)) { addError( "Annotation @" + name + " is not allowed on element " + AnnotationNode.targetToName(target), visited); } visitDeprecation(node, visited); visitOverride(node, visited); } checkForDuplicateAnnotations(node, nonSourceAnnotations); } private void checkForDuplicateAnnotations(AnnotatedNode node, Map<String, List<AnnotationNode>> nonSourceAnnotations) { for (Map.Entry<String, List<AnnotationNode>> next : nonSourceAnnotations.entrySet()) { if (next.getValue().size() > 1) { ClassNode repeatable = null; AnnotationNode repeatee = next.getValue().get(0); for (AnnotationNode anno : repeatee.getClassNode().getAnnotations()) { if (anno.getClassNode().getName().equals("java.lang.annotation.Repeatable")) { Expression value = anno.getMember("value"); if (value instanceof ClassExpression && value.getType().isAnnotationDefinition()) { repeatable = value.getType(); break; } } } if (repeatable != null) { AnnotationNode collector = new AnnotationNode(repeatable); if (repeatee.hasRuntimeRetention()) { collector.setRuntimeRetention(true); } else if (repeatable.isResolved()) { Class<?> repeatableType = repeatable.getTypeClass(); Retention retention = repeatableType.getAnnotation(Retention.class); collector.setRuntimeRetention( retention != null && retention.value().equals(RetentionPolicy.RUNTIME)); } else { for (AnnotationNode annotation : repeatable.getAnnotations()) { if (annotation.getClassNode().getName().equals("java.lang.annotation.Retention")) { Expression value = annotation.getMember("value"); assert value != null; Object retention = evaluateExpression(value, source.getConfiguration()); collector.setRuntimeRetention( retention != null && retention.toString().equals("RUNTIME")); break; } } } collector.addMember("value", new ListExpression(next.getValue().stream() .map(AnnotationConstantExpression::new).collect(Collectors.toList()))); node.getAnnotations().removeAll(next.getValue()); node.addAnnotation(collector); } } } } private static void visitDeprecation(AnnotatedNode node, AnnotationNode visited) { if (visited.getClassNode().isResolved() && visited.getClassNode().getName().equals("java.lang.Deprecated")) { if (node instanceof MethodNode) { MethodNode mn = (MethodNode) node; mn.setModifiers(mn.getModifiers() | Opcodes.ACC_DEPRECATED); } else if (node instanceof FieldNode) { FieldNode fn = (FieldNode) node; fn.setModifiers(fn.getModifiers() | Opcodes.ACC_DEPRECATED); } else if (node instanceof ClassNode) { ClassNode cn = (ClassNode) node; cn.setModifiers(cn.getModifiers() | Opcodes.ACC_DEPRECATED); } } } // TODO GROOVY-5011 handle case of @Override on a property private void visitOverride(AnnotatedNode node, AnnotationNode visited) { ClassNode annotationType = visited.getClassNode(); if (annotationType.isResolved() && annotationType.getName().equals("java.lang.Override")) { if (node instanceof MethodNode && !Boolean.TRUE.equals(node.getNodeMetaData(Verifier.DEFAULT_PARAMETER_GENERATED))) { boolean override = false; MethodNode origMethod = (MethodNode) node; ClassNode cNode = origMethod.getDeclaringClass(); if (origMethod.hasDefaultValue()) { List<MethodNode> variants = cNode.getDeclaredMethods(origMethod.getName()); for (MethodNode m : variants) { if (m.getAnnotations().contains(visited) && isOverrideMethod(m)) { override = true; break; } } } else { override = isOverrideMethod(origMethod); } if (!override) { addError( "Method '" + origMethod.getName() + "' from class '" + cNode.getName() + "' does not override " + "method from its superclass or interfaces but is annotated with @Override.", visited); } } } } private static boolean isOverrideMethod(MethodNode method) { ClassNode cNode = method.getDeclaringClass(); ClassNode next = cNode; outer: while (next != null) { Map<String, ClassNode> genericsSpec = createGenericsSpec(next); MethodNode mn = correctToGenericsSpec(genericsSpec, method); if (next != cNode) { ClassNode correctedNext = correctToGenericsSpecRecurse(genericsSpec, next); MethodNode found = getDeclaredMethodCorrected(genericsSpec, mn, correctedNext); if (found != null) break; } List<ClassNode> ifaces = new ArrayList<>(Arrays.asList(next.getInterfaces())); while (!ifaces.isEmpty()) { ClassNode origInterface = ifaces.remove(0); if (!origInterface.equals(ClassHelper.OBJECT_TYPE)) { genericsSpec = createGenericsSpec(origInterface, genericsSpec); ClassNode iNode = correctToGenericsSpecRecurse(genericsSpec, origInterface); MethodNode found2 = getDeclaredMethodCorrected(genericsSpec, mn, iNode); if (found2 != null) break outer; Collections.addAll(ifaces, iNode.getInterfaces()); } } ClassNode superClass = next.getUnresolvedSuperClass(); if (superClass != null) { next = correctToGenericsSpecRecurse(genericsSpec, superClass); } else { next = null; } } return next != null; } private static MethodNode getDeclaredMethodCorrected(Map genericsSpec, MethodNode mn, ClassNode correctedNext) { for (MethodNode declared : correctedNext.getDeclaredMethods(mn.getName())) { MethodNode corrected = correctToGenericsSpec(genericsSpec, declared); if (ParameterUtils.parametersEqual(corrected.getParameters(), mn.getParameters())) { return corrected; } } return null; } /** * Check if the current runtime allows Annotation usage. * * @return true if running on a 1.5+ runtime */ protected boolean isAnnotationCompatible() { return CompilerConfiguration.isPostJDK5(this.source.getConfiguration().getTargetBytecode()); } }