Java Code Examples for javassist.bytecode.ClassFile#addAttribute()

Class<? extends T> generate(Class<? extends Repository> baseImpl) {
    try {
        CtClass cc = createClass(
                getClassName(baseImpl, getCounter(repositoryInterface).incrementAndGet()),
                baseImpl
        );
        ClassFile cf = cc.getClassFile();
        ConstPool constPool = cf.getConstPool();

        cc.setModifiers(Modifier.PUBLIC);

        cc.setInterfaces(new CtClass[]{classPool.getCtClass(repositoryInterface.getName())});

        if (hasGenericConstructor(baseImpl)) {
            cc.addConstructor(createConstructor(constPool, cc));
        } else {
            cc.addConstructor(createDefaultConstructor(cc));
        }

        cf.addAttribute(createQualifierAttribute(constPool, getQualifier(baseImpl)
                .orElseThrow(() -> new NotFoundException("Qualifier annotation not found"))));

        return cast(cc.toClass(
                classLoader,
                DefaultRepositoryCollector.class.getProtectionDomain())
        );
    } catch (CannotCompileException | NotFoundException e) {
        throw BusinessException.wrap(e, BusinessErrorCode.UNABLE_TO_CREATE_DEFAULT_IMPLEMENTATION)
                .put("interface", repositoryInterface)
                .put("base", baseImpl);
    }
}
 

/**
 * 自动生成Repository接口的实现类并以字节的形式返回.
 * 
 * @param repositoryClazz repository class
 * @return 生成的类字节码
 */
public static byte[] generateBytes(Class<?> repositoryClazz) {

	// 生成类
	ClassPool pool = ClassPool.getDefault();
	// web容器中的repository 需要增加classPath
	ClassClassPath classClassPath = new ClassClassPath(repositoryClazz);
	pool.removeClassPath(classClassPath);
	pool.insertClassPath(classClassPath);
	String className = repositoryClazz.getName() + Placeholder.REST_SUF;
	CtClass ctClass = pool.makeClass(className);

	ClassFile ccFile = ctClass.getClassFile();
	ConstPool constpool = ccFile.getConstPool();

	try {
		// 增加接口
		ctClass.setInterfaces(new CtClass[] { pool.get(repositoryClazz.getName()) });

		// 增加字段
		CtClass executor = pool.get(repositoryClazz.getName());
		CtField field = new CtField(executor, "d", ctClass);
		field.setModifiers(Modifier.PRIVATE);
		FieldInfo fieldInfo = field.getFieldInfo();
		// 标识属性注解
		AnnotationsAttribute fieldAttr = new AnnotationsAttribute(constpool, AnnotationsAttribute.visibleTag);
		javassist.bytecode.annotation.Annotation autowired = new javassist.bytecode.annotation.Annotation(
				"javax.inject.Inject", constpool);
		fieldAttr.addAnnotation(autowired);
		fieldInfo.addAttribute(fieldAttr);
		ctClass.addField(field);
		
		AsmRepository.addGetInterfaceClassMethod(repositoryClazz, ctClass);
		
		// 标识类注解
		AnnotationsAttribute classAttr = new AnnotationsAttribute(constpool, AnnotationsAttribute.visibleTag);
		javassist.bytecode.annotation.Annotation singAnn = new javassist.bytecode.annotation.Annotation(
				"javax.inject.Singleton", constpool);
		classAttr.addAnnotation(singAnn);
		ccFile.addAttribute(classAttr);

		// 实现抽象方法
		Method[] methods = repositoryClazz.getMethods();
		for (Method method : methods) {
			if (!method.isDefault()) {
				CtMethod cm = CtMethod.make(AsmRepository.getMethodDef(method) + "{return d."+method.getName()+"($$);}", ctClass);
				// 标识方法注解
				AnnotationsAttribute methodAttr = new AnnotationsAttribute(constpool,
						AnnotationsAttribute.visibleTag);
				javassist.bytecode.annotation.Annotation extendsAnn = new javassist.bytecode.annotation.Annotation(
						"org.fastquery.core.Extends", constpool);
				ArrayMemberValue arrayMemberValue = new ArrayMemberValue(constpool);
				Annotation[] mas = method.getAnnotations();
				ClassMemberValue[] cmvs = new ClassMemberValue[mas.length];
				for (int i = 0; i < mas.length; i++) {
					cmvs[i] = new ClassMemberValue(mas[i].annotationType().getName(), constpool);
				}
				arrayMemberValue.setValue(cmvs);
				extendsAnn.addMemberValue("value", arrayMemberValue);
				methodAttr.addAnnotation(extendsAnn);
				MethodInfo info = cm.getMethodInfo();
				info.addAttribute(methodAttr);
				ctClass.addMethod(cm);
			}
		}
		
		return ctClass.toBytecode();

	} catch (Exception e) {
		throw new ExceptionInInitializerError(e);
	}
}