AppDev-Prelim 1.pdf

BACKGROUND TO AND PURPOSE OF SOFTWARE ENGINEERING Applying software engineering technology to successfully develop software that becomes more multifunctional and bigger in scale, which provides technologies that support systematic management to resolve the expected difficulties throughout the...

BACKGROUND TO AND PURPOSE OF SOFTWARE ENGINEERING Applying software engineering technology to successfully develop software that becomes more multifunctional and bigger in scale, which provides technologies that support systematic management to resolve the expected difficulties throughout the entire process, ranging from equipment analysis to maintenance. 3 key elements of a successful Software 1. Process - Process of applying definition of systematic business methods and flow 2. People - Organization and people equipped with specialized knowledge 3. Technology - Infrastructure and technology required for efficient operation of the defined work method s and organizational personnel 1950s - concept of software engineering like hardware engineering began to be introduced to implement software development projects 1960s - software engineering was introduced because of “software crisis” due to the lack of experience, competence, and skilled engineers 1970s- software devs became scarce and demand for software increased,, adopted “coding first correction later” approach to solve this problem, FOUR KEY ELEMENTS OF SOFTWARE ENGINEERING A discipline that studies the overall life cycle of software - such as development, operation, and maintenance - systematically, descriptively and quantitatively. These elements make it possible to produce top quality software and deliver it according to a given cost and schedule. 1. Method - project planning and estimation, system and software analysis, data structure, program structure, algorithm, coding, testing, and maintenance tasks - Centered on a specific language (OOP), or graphical notation, are introduced from time to time. - A series of evaluation standards for software quality 2. Tool - Automated or semi-automated method used to improve productivity/consistency when doing a task - Example tools are: requirements management tools, modeling tools, configuration management tools, change management tools - If these are integrated in such a way that the information created by one tool can be used by other tools then it is set as a system that supports software dev. 3. Procedure - Combines method and tools to develop software in a rational and timely manner - Defines the applied method, required deliverables, controls to guarantee quality and assist coordinate adjustment, and the sequence of milestones that enable software managers to evaluate progress 4. People - performed by employees,, depends more heavily on people - Practically impossible to summarize software dez w/out people LIFECYCLE OF SOFTWARE DEVELOPMENT - The entire process from understanding the user environment and problems to operation and maintenance. - Composed of: Feasibility Review->Development Planning->Requirement Analysis->Design->Implementation->Test->Operation->Maintenance Purpose Calculate the project costs and draw up a development plan, and to configure the basic framework Standardize the terms Manage a project Selecting a software lifecycle Important activity for corporations to tailor the development process of a project Based on risk and uncertainty of system development and understanding it Selected model should be able to minimize the risks and uncertainties Waterfall, prototype, evolutionary, and incremental are the most represented life cycle models Types of software lifecycle models V Model - clearly shows the activities that should be performed while implementing the project to project managers and developers - Helps customers who do not know much about this area to understand the principles of software dev - Ideal lifecycle model identifies and clarifies all system reqs - Can be used even when the reqs aren't clear. - Estimation, planning, and confirmation of a project are limited to only requirement analysis and identification phase - If reqs not clear then initial proj plan should specify the start/end dates expected by the customers  - Example: The implementation of a standard communication protocol Characteristic: - Easy to apply; emphasizes project verification and validation (model explains very well) - Effectively manage the start/end of dev activities and the project can be clearly defined Prototyping - Developing a system or part of a system to understand a system or to solve such issues as risks or uncertainties - Make them understand what is needed and what should be developed - Independent lifecycle model or can be applied to the dev phase of waterfall or v model 1. Throw away - rejected which means ilisan throw dat shit away 2. Revolutionary - guds and magamit na siya(feasible and usable) Types of Software development Methodologies Incremental - mura siyag i++ - Useful when the system dev time needs to be reduced - Useful when most of the reqs are defined, but improvements can be made as time goes by - Reduce risk of external interfaces in the early phase Evolutionary model - same with incremental but the dev phase for the entire system is reiterated several times. Each system provides all of the functions to the user - Changes are identified when a system is developed and used.(Kung mag change kay machange sad tanan functions etc) - Suitable when overall system specification is not certain or product should be continually improved Spiral - done together with incremental(iterative process; loop kunohay) Agile - Scrum and xp are generally used together; Xp used in early days; Lean is mainly used with scrum - comprehensively adopted to effectively respond to such rapid changes Types of Agile Methodologies Scrum , Ken Schwaber/ Jeff Sutherland ○ Designed for project management ○ A representative type of empirical management technique based on estimation and adjustment ○ Modelled after “the new Product development Game” by hirotaka Takeuch and Ikunjuro Nonaka published in the Harvard Business Review in 1986 ○ Scrum consist of Three fundamental units: Product Owner - manages the creation product backlog Scrum Master - removes any factors that disturb the team’s work Scrum Team - identifies functions during a sprint using user stories (Composed of 5-9 members) ○ Scrum Process Sprint: refers to repetitive development in units of 1-4 weeks Three meetings: Daily Scrum, Sprint Plan, Sprint Review Three deliverables: Product backlog, Sprint backlog Burndown Chart  ○ Characteristics of Scrum: Transparency -enables the user to effectively understand the status of a project Timeboxing - time is limited i.e daily scrum is limited to 15 mins each day Communication - makes comms among team members smooth EXtreme Programming(XP), Kent Bech/ Erich Gamma ○ A lightweight development method for small/medium-sized dev orgs ○ Related to dev techniques such as Test-Driven Development(TTD) ○ Applied together with diff agile dev methods such as scrum, rather than a standalone methodology ○ Composed of value and the practice of achieving the value when it is applied, a principle is needed to balance the two  ○ Iterative development methodology Lean software development, Mary Popendic Tom Poppendieck Agile Unified Process(AUP), Scott Ambler Waterfall ○ Proceed With analysis design and implementation sequentially ○ Expensive and slow to implement ○ Less usable for general software developers ○ 1980s - methods of boosting software dev were studied to efficiently develop software with increasing reusability SOFTWARE DEVELOPMENT METHODOLOGY - Defines each dev phase, the activities to perform in each phase, deliverables, verification procedure and completion criteria - Defines standardized method and procedure and support tool Necessity of SDM Improved dev productivity Effective proj management Providing a means of communication Assuring quality at a certain level Software Development Phases Requirement Analysis - hardest thing in software dev is deciding exactly what to develop - The first step and the phase of understanding what the user needs - Critical phase that can reduce the dev costs - Conceptual Step Design - the first step in physical realization - Directly affects quality - Stability deteriorates if not designed properly Implementation - The goal is to program it in a way that the requirements can be satisfied based on the design specification (program should be written according to the description in the detailed design and user’s guide) - One of the most important task is to decide on a coding standard and write the code clearly based on that standard Testing - refers to a series of processes to inspect and evaluate whether the system satisfies the prescribed reqs, etc, using manual or automated method -the final step in assuring software qual; includes a quality eval SCT Constraints S - Scope C - Cost T - Time SMART Criteria S -Specific M - Measurable A - Attainable R - Realistic T - time bounded Software Quality: Usability ○ Uses can learn it fast and get their job done easily Efficiency ○ Does not waste resource such as CPU time and memory Reliability ○ It does what is required to do without failing Maintainability ○ It can be easily changed Reusability ○ Its parts can be used in other projects,, so reprogramming Is not needed CRUD - (HTTP) Post, Get ,Put ,Delete API - Application Programming interface Entity - a package that contains classes(defines all packages) -Student entity -Course Entity Repository - a package that contains interfaces -StudentRepo -CourseRepo Service- Package that contains CRUD ,business rules, and logics -StudentService -CourseService Controller - specific endpoints -StudentController -CourseController