Software attributes including functional attributes and quality attributes, software architecture, but the focus is on quality attributes. The basic needs of architecture mainly in meeting the functional properties, focus software quality attributes. Quality attributes include a lot of software, there are a variety of different expressions and classification. The quality attributes generally divided into three categories:
● quality attributes of the system. Availability, modifiability, performance, security, testability, and ease of use.
● commercial property affected by the architecture (time to market).
● related to the architecture itself some quality attributes (such as the concept of integrity), they will indirectly affect other quality attributes, such as modifiability.
1. General quality property scene
How to describe the quality attributes demand? It is generally used as a quality attribute scene specification. The scene is a quality attribute for the needs of a specific quality attributes. It consists of six parts:
Stimuli: This is a stimulus that generates the entity (person, or any other computer system stimulators).
Stimulation: stimulation when the condition of the stimulation system reaches consideration.
Environment: The stimulus occurs within certain conditions. When stimulation occurs, the system may be overloaded, or run, it could be otherwise.
Products: a product is stimulated. This may be the whole system, it could be part of the system.
Response: The response is action taken after stimulation arrival.
Response Metrics: When the response occurs, should be able to measure it in some way, in order to test the demand.
2. The availability of general scene: aspects of interest including the frequency of system failure, what happens when a failure occurs, allow the system how long is a non-normal operation, when you can fail safely, and how to avoid trouble which requires notification when a failure occurs.
| Part of the scene |
Possible values |
| source |
Internal system, the external system |
| stimulate |
Negligence, collapse time, in response to |
| product |
A processor system, a communication channel, persistent memory, process |
| surroundings |
Normal operation, degraded mode |
| response |
The system should detect events, and one or more of the following activities: Its record notify the appropriate parties, including the event source users and other systems is prohibited according to the rules defined cause errors or failures Unavailable within a pre-specified time interval, which time interval depends on the criticality of the system operating in a normal or degraded mode |
| Response Metrics |
The system must be available in the time interval Available time The system may be spaced in time to run in a degraded mode Time to Repair |
3. modifiability general scenario.
| Part of the scene |
Possible values |
| source |
End-users, developers, system administrators, |
| stimulate |
I want to add, delete, modify, alter function, quality attributes, capacity |
| product |
System user interface, platform, environment or system that interacts with the target system |
| surroundings |
At run time, compile time, build, design |
| response |
Find architectures need to change the location to be modified without affecting the other functions of the changes made to test, deploy your changes |
| Response Metrics |
According to the cost impact of the number of elements of the measure, effort, money; the modification caused by other features or quality attributes The impact of |
4. The general performance scene.
| Part of the scene |
Possible values |
| source |
A large number of independent sources, may come from within the system |
| stimulate |
Regular event arrives; random events arrive; reach accident |
| product |
system |
| surroundings |
Normal mode; overload mode |
| response |
Processing stimuli; changes in service levels |
| Response Metrics |
Waiting for the event, duration, throughput, jitter, missing rate, data loss |
The general safety scenarios.
| Part of the scene |
Possible values |
| source |
Correct identification, identity unknown or incorrect identification of the person or system from its internal / external; through authorized / unauthorized It accesses the limited resources / significant resources |
| stimulate |
attempt Display data, change / delete data, access to system services, reduce the availability of system services |
| product |
Data system services, system |
| surroundings |
Online or offline, intranet or off network, is connected to a firewall or directly connected to the network |
| response |
The user identity authentication; hide the user's identity; to block access to data or services; allow access to data or services Service; grant or revoke permission to access data or services; access based on the identity of the recording / modify or attempt to access / modify the number of Data / service; stored in a format unreadable data; identifying unexplained high demand for services; or notify the user Another system, and limit the availability of services |
| Response Metrics |
With a probability of success, said safety precautions to avoid the time required / effort / resources; the possibility of an attack is detected; 确定攻击或访问/修改数据或服务的个人的可能性；在拒绝服务攻击的情况下仍然获得 服务的百分比；恢复数据/服务；被破坏的数据/服务和/或被拒绝的合法访问的范围 |
6. 可测试性一般场景。
| 场景的部分 |
可能的值 |
| 源 |
开发人员、增量开发人员、系统验证人员、客户验收测试人员、系统用户 |
| 刺激 |
已完成的分析、架构、设计、类和子系统集成；所交付的系统 |
| 制品 |
设计、代码段、完整的应用 |
| 环境 |
设计时、开发时、编译时、部署时 |
| 响应 |
提供对状态值的访问、提供所计算的值、准备测试环境 |
| 响应度量 |
已执行的可执行语句的百分比 如果存在缺陷出现故障的概率 执行测试的时间 测试中最长依赖的长度 准备测试环境的时间 |
7. 易用性一般场景
| 场景的部分 |
可能的值 |
| 源 |
最终用户 |
| 刺激 |
想要 学习系统特性、有效使用系统、使错误的影响最低、适配系统、对系统满意 |
| 制品 |
系统 |
| 环境 |
在运行时或配置时 |
| 响应 |
系统提供以下一个或多个响应来支持“学习系统特性” 帮助系统与环境联系紧密；界面为用户所熟悉；在不熟悉的环境中，界面是可以使用的 系统提供以下一个或多个响应来支持“有效 使用系统” 数据和/或命令的聚合；已输入的数据和/或命令的重用；支持在界面中的有效导航；具有一致操作的不同视图；全面搜索；多个同事进行的活动 系统提供以下一个或多个响应来“使错误的影响最低” 撤销；取消；从系统故障中恢复；识别并纠正用户错误；检索忘记的密码；验证系统资源 系统提供以下一个或多个响应来“适配系统” 定制能力；国际化 系统提供以下一个或多个响应来使客户“对系统的满意” 显示系统状态；与客户的节奏合拍 |
| 响应度量 |
任务时间、错误数量、解决问题的数量、用户满意度、用户知识的获得、成功操作在总 操作中所占的比例、损失的时间/丢失的数据量 |
8. 质量属性场景
| 质量属性 |
刺激 |
| 可用性 |
不期望的事件、期望的时间不发生 |
| 可修改性 |
请求添加删除改变功能、平台、质量属性或容量 |
| 性能 |
周期性的、随机的或偶然的 |
| 安全性 |
试图 显示、修改、改变/删除信息、访问或降低系统服务的可用性 |
| 可测试性 |
系统开发阶段的完成 |
| 易用性 |
想要 学习系统特性、有效使用系统、使错误的影响最低、适配系统、对系统满意 |