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/*
* Copyright (C) 2015-2021 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.javac.handlers;
import static lombok.core.handlers.HandlerUtil.handleExperimentalFlagUsage;
import static lombok.javac.handlers.JavacHandlerUtil.*;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCModifiers;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCTypeParameter;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.Name;
import lombok.ConfigurationKeys;
import lombok.core.AST.Kind;
import lombok.core.AnnotationValues;
import lombok.core.HandlerPriority;
import lombok.experimental.UtilityClass;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
import lombok.javac.JavacTreeMaker;
import lombok.spi.Provides;
/**
* Handles the {@code @UtilityClass} annotation for javac.
*/
@HandlerPriority(-4096) //-2^12; to ensure @FieldDefaults picks up on the 'static' we set here.
@Provides
public class HandleUtilityClass extends JavacAnnotationHandler<UtilityClass> {
@Override public void handle(AnnotationValues<UtilityClass> annotation, JCAnnotation ast, JavacNode annotationNode) {
handleExperimentalFlagUsage(annotationNode, ConfigurationKeys.UTILITY_CLASS_FLAG_USAGE, "@UtilityClass");
deleteAnnotationIfNeccessary(annotationNode, UtilityClass.class);
JavacNode typeNode = annotationNode.up();
if (!checkLegality(typeNode, annotationNode)) return;
changeModifiersAndGenerateConstructor(annotationNode.up(), annotationNode);
}
private static boolean checkLegality(JavacNode typeNode, JavacNode errorNode) {
if (!isClass(typeNode)) {
errorNode.addError("@UtilityClass is only supported on a class.");
return false;
}
// It might be an inner class. This is okay, but only if it is / can be a static inner class. Thus, all of its parents have to be static inner classes until the top-level.
JavacNode typeWalk = typeNode;
while (true) {
typeWalk = typeWalk.up();
switch (typeWalk.getKind()) {
case TYPE:
JCClassDecl typeDef = (JCClassDecl) typeWalk.get();
if ((typeDef.mods.flags & (Flags.STATIC | Flags.ANNOTATION | Flags.ENUM | Flags.INTERFACE)) != 0) continue;
if (typeWalk.up().getKind() == Kind.COMPILATION_UNIT) return true;
errorNode.addError("@UtilityClass automatically makes the class static, however, this class cannot be made static.");
return false;
case COMPILATION_UNIT:
return true;
default:
errorNode.addError("@UtilityClass cannot be placed on a method local or anonymous inner class, or any class nested in such a class.");
return false;
}
}
}
private void changeModifiersAndGenerateConstructor(JavacNode typeNode, JavacNode errorNode) {
JCClassDecl classDecl = (JCClassDecl) typeNode.get();
boolean makeConstructor = true;
classDecl.mods.flags |= Flags.FINAL;
boolean markStatic = true;
if (typeNode.up().getKind() == Kind.COMPILATION_UNIT) markStatic = false;
if (markStatic && typeNode.up().getKind() == Kind.TYPE) {
JCClassDecl typeDecl = (JCClassDecl) typeNode.up().get();
if ((typeDecl.mods.flags & (Flags.INTERFACE | Flags.ANNOTATION)) != 0) markStatic = false;
}
if (markStatic) classDecl.mods.flags |= Flags.STATIC;
for (JavacNode element : typeNode.down()) {
if (element.getKind() == Kind.FIELD) {
JCVariableDecl fieldDecl = (JCVariableDecl) element.get();
fieldDecl.mods.flags |= Flags.STATIC;
} else if (element.getKind() == Kind.METHOD) {
JCMethodDecl methodDecl = (JCMethodDecl) element.get();
if (methodDecl.name.contentEquals("<init>")) {
if (getGeneratedBy(methodDecl) == null && (methodDecl.mods.flags & Flags.GENERATEDCONSTR) == 0) {
element.addError("@UtilityClasses cannot have declared constructors.");
makeConstructor = false;
continue;
}
}
methodDecl.mods.flags |= Flags.STATIC;
} else if (element.getKind() == Kind.TYPE) {
JCClassDecl innerClassDecl = (JCClassDecl) element.get();
innerClassDecl.mods.flags |= Flags.STATIC;
}
}
if (makeConstructor) createPrivateDefaultConstructor(typeNode);
}
private void createPrivateDefaultConstructor(JavacNode typeNode) {
JavacTreeMaker maker = typeNode.getTreeMaker();
JCModifiers mods = maker.Modifiers(Flags.PRIVATE, List.<JCAnnotation>nil());
Name name = typeNode.toName("<init>");
JCBlock block = maker.Block(0L, createThrowStatement(typeNode, maker));
JCMethodDecl methodDef = maker.MethodDef(mods, name, null, List.<JCTypeParameter>nil(), List.<JCVariableDecl>nil(), List.<JCExpression>nil(), block, null);
JCMethodDecl constructor = recursiveSetGeneratedBy(methodDef, typeNode);
JavacHandlerUtil.injectMethod(typeNode, constructor);
}
private List<JCStatement> createThrowStatement(JavacNode typeNode, JavacTreeMaker maker) {
JCExpression exceptionType = genJavaLangTypeRef(typeNode, "UnsupportedOperationException");
List<JCExpression> jceBlank = List.nil();
JCExpression message = maker.Literal("This is a utility class and cannot be instantiated");
JCExpression exceptionInstance = maker.NewClass(null, jceBlank, exceptionType, List.of(message), null);
JCStatement throwStatement = maker.Throw(exceptionInstance);
return List.of(throwStatement);
}
}
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