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Explore the historical progression of programming language generations, translation software function, and integrated application development tools. Understand the role of compilers, interpreters, and link editing in software development processes. Delve into the significance of methodological approaches in building the next generation of software applications.
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Chapter 10Application Development Chapter Outline The Application Development Process Programming Languages Compilation Link Editing Interpreters Focus - Java Symbolic Debugging Integrated Application Development Tools Focus – Oracle JDeveloper Focus - Building the Next Generation of Application Software
Chapter Goals • Describe the application development process and the role of methodologies, models, and tools • Compare and contrast programming language generations • Explain the function and operation of program translation software, including assemblers, compilers, and interpreters • Describe link editing, and contrast static and dynamic linking • Describe integrated application development software, including programmer’s workbenches and CASE tools
The Application Development Process • Follows a development methodology • Develops a set of models • Uses automated tools
Systems Development Life Cycle (SDLC) • Follow disciplines and iterations of the Unified Process (UP) • Usually includes two sets of models • System requirements model • Design model
Methodologies and Models • Methodology • Integrated collection of models, tools, and techniques • UP employs object-oriented analysis, design, and deployment models • Class diagrams document user and system requirements
Tools • Wide array to support or completely automate software development tasks • Proper tool selection is a critical and difficult undertaking
This Material Continued In CIS 242Introduction to Systems Analysis and Design4 hours, 4 credits Study of a computer system life cyclevia a structured approach:problem definition, feasibility study,cost estimation, analysis, design,implementation, testing and maintenance.Hardware and software organization.Several case studies will be considered.PREREQ: CIS 211.
Programming Languages • Instruct computer to perform a task • Sometimes called code • Programmer goals • Make language easier for people to understand • Develop languages and development approaches that require people to write fewer instructions to accomplish a task
Programming Languages • Summary of capabilities of recent generations • Instruction explosion • Database access • Support for GUIs • Nonprocedural programming • All but 1GL must be translated into CPU instructions prior to execution (compilers and interpreters)
First-Generation Languages • Required programmers to remember binary codes that represented each CPU instruction and to specify all operands as binary numbers • Tedious to program; error-prone
Second-Generation Languages • Use mnemonics to represent variables (program instruction memory address) and labels (data item memory address) • Easier to manipulate than binary numbers; assembler translates program into binary CPU instructions • Common in 1950s
Third-Generation Languages • Use mnemonics to represent instructions, variables, and labels • Have degree of instruction explosion greater than 1:1 • Translated with compilers, link editors, and interpreters • Machine independent • Developed before GUIs, database managers, and Internet
Fourth-Generation Languages • Majority were proprietary • many were optional components of database management systems • Most support mixture of procedural and nonprocedural instructions
Fifth-Generation Languages • Nonprocedural language suitable for developing software that mimics human intelligence • Rule processor accepts a starting state as input and iteratively applies rules to achieve a solution • First appeared in 1960s; not widely used until 1980s
Object-Oriented Programming (OOP) Languages • View data and programs as two parts of integrated whole (object) • Promote reusability and portability of source code • Uniquely suited to developing real-time programs • Not clear successors to 5GLs; neither nonprocedural nor exclusively used for developing artificial intelligence
OOP Languages Objects reside in a specific location, wait for messages to arrive, and return a response.
Scripting Languages • Enable programmers to develop applications that do most of their work by calling other applications and system software • Enable rapid assembly of application software by “gluing” together capabilities of other programs • Evolved from 4GLs, though most now incorporate OOP concepts
Programming Language Standards • Set by ANSI and ISO • Include definitions of: • Language syntax and grammar • Machine behavior for each instruction or statement • Test programs with expected warnings, errors, and execution behavior • Guarantee program portability among operating systems and application programs
Compilation • Translates an entire source code file, building a symbol table and object code file as output
Compiler 1. Checks for errors in syntax 2. Issues warnings and/or error messages 3. Builds and uses a Symbol Table as it works • stores information about data items and program components 4. Generates CPU instructions and library calls to carry out the source code instructions 5. Creates an object code file as output
Source Code Instruction Types Data declarations A data declaration creates an entry in the symbol table Data operations A data operation becomes a series of data transformation instructions Control structures A control structure becomes a series of control flow instructions Subprogram calls
Data Declarations • Define name and data type of program variables • Stored in memory allocated by compiler
Symbol Table The compiler updates a symbol table to keep track of data names, types, and assigned memory addresses.
Data Operations • Instructions that update or compute a data value • Translated by compiler into equivalent sequence of data movement and data transformation instructions for target CPU • Compiler refers to entries in symbol table to determine source and destination memory addresses for data movement instructions
Control Structures • Source code instructions that control the execution of other source code instructions • Common thread is transfer of control among CPU instructions
Function Calls • Named instruction sequences executed by call instructions • Transfer control to the instruction following the call by executing a return instruction
Implementing Call and Return Instructions • Compiler generates CPU instructions to: • Pass input parameters to the function • Save the value of the IP as a Return Address • Load the IP with the address of the subprogram • Transfer control to the function • Execute CPU instructions within the function • Pass output parameters back to the caller • Load the IP with the saved Return Address • Transfer control back to the caller
CompilationJust The First Step source code translated by compiler into object code linked with library routines to make load module loaded into memory by operating system as runnable machine instructions
Link Editing • Statically links external reference calls in object code to library functions; combines them into a single file containing executable code • Can dynamically link external calls by statically linking them to an OS service function that loads and executes dynamic-link library (DLL) functions at run time • Always used by interpreters
Key Benefits of Link Editors in Program Translation • A single executable program can be constructed from multiple object code files compiled at different times • A single compiler can generate executable programs that run under multiple operating systems
Dynamic and Static Linking • Static linking • Library and other subroutines cannot be changed once inserted into executable code • Dynamic linking • Performed during program loading or execution
Advantages of Dynamicand Static Linking • Dynamic • Smaller application program executable files • Flexibility • Static • Execution speed • Improves reliability and predictability of executable programs
Interpreters • Interleave source code translation, link editing, and execution, one source code instruction at a time • Advantage (vs. compilation) • Provide flexibility to incorporate new or updated code into an application program (dynamic linking) • Disadvantage (vs. compilation) • Increase memory and CPU requirements during program execution
Java • Object-oriented programming language and program execution environment • Maximizes reliability of applications and reusability of existing code • Has a standardized target machine language for Java interpreters and compilers • Drawback: Reduced execution speed due to use of interpreted byte codes and OS translation
JavaHow Java and the JVMrelate to the CPU and the OS
Features of Java • Provision of compilers and virtual machines at little or no cost • Incorporation of JVMs into Web browsers • Increasing development of application software that uses a Web browser as primary I/O device • Ability of Java programs to execute on any combination of computer hardware and OS
Symbolic Debugging • Use of an automated tool for testing executable programs; able to: • Trace calls to specific source code statements or subroutines • Trace changes to variable contents • Execute source code instructions one at a time • Detect and report run-time errors to programmer
Symbolic Debugger • Uses symbol table, memory map, and source code files to trace memory addresses to specific source code statements and variables • Inserts debugging checkpoints after each source code instruction; program execution can be paused • Debugging vs. production/distribution version • Incorporated directly in most interpreters