Download Fuzzy Fault Management for Rotating Machinery

Software Development
prietary© 1997
Evolution of Programming Languages
• Basic cycle of improvement
– Experience software difficulties
– Theory - develop new concepts
– Evaluation - build new languages
• History
– Machine language
– Assembly language
– FORTRAN, COBOL
– Pascal, C, Smalltalk
– Ada, C++, Java
University of Houston-Clear Lake
Software Development
prietary© 1997
Java
•
•
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•
•
•
•
•
•
•
•
Simple
Object-oriented
Distributed
Interpreted
Robust
Secure
Architecture neutral
Portable
High performance
Multi-threaded
Dynamic language
University of Houston-Clear Lake
Software Development
prietary© 1997
Object-Oriented Languages
• Abstraction
• Encapsulation
• Inheritance
• Polymorphism
University of Houston-Clear Lake
Object-oriented
Software Development
prietary© 1997
Abstraction
Real World Object
Abstraction of the Object
Color
Price
Options
Position
Velocity
Forces
Width
Height
Weight
University of Houston-Clear Lake
Object-oriented
Software Development
prietary© 1997
Encapsulation
Data
and
Operations
Access to object’s data is controlled
University of Houston-Clear Lake
Object-oriented
Software Development
prietary© 1997
Inheritance
University of Houston-Clear Lake
Object-oriented
Software Development
prietary© 1997
Polymorphism
• Object-specific operations
• Overloading of method names
“abc”
“de”
“abcde”
String
String
3
4
7
float
float
float
String
University of Houston-Clear Lake
Distributed
Software Development
prietary© 1997
Distributed
• High-level support for networking
• URL and other classes from java.net package
• Easy to read a remote file or other resource
• Can invoke remote methods
• Can download and run code from across the Internet
University of Houston-Clear Lake
Interpreted
Software Development
prietary© 1997
Interpreted
• Java compiler generates byte-code for the JVM
– the Java Virtual Machine
Java byte code
Java Virtual Machine
Computer XYZ
University of Houston-Clear Lake
Portable
Software Development
prietary© 1997
Architecture-Neutral and Portable
• The Java byte-code is architecture neutral because
it can be executed on any machine that supports
the Java Virtual Machine
• No implementation-dependent aspects to the language
– size of each of the primitive data types is specified
• Few platform dependencies
• Write - Once - Run - Many
University of Houston-Clear Lake
Simple
Software Development
prietary© 1997
Simple
ABC
• Number of language constructs has been kept small
• Language is similar to C and C++
• No header files
• No preprocessor
• No struct statement
• No goto statement
• No pointers
• Automatic garbage collection
University of Houston-Clear Lake
Robust
Software Development
prietary© 1997
Robust
• Strongly-typed
• Better compile-time error checking
• No pointer-related bugs
• No memory leaks
• Support for exception handling
• Explicit method declarations are required
• Casts of objects are checked at compile time
University of Houston-Clear Lake
Secure
Software Development
prietary© 1997
Secure
• Several layers of security protection to protect
against malicious code
• Pointers cannot be forged
• Memory cannot be accessed beyond the limits of an
array or string’s dimensions
• Byte-code verification prevents stack overflows and
illegal byte-codes
• Sandbox model - applets cannot access local file
system
• Support for digital signatures for untrusted code
University of Houston-Clear Lake
High-Performance
Software Development
prietary© 1997
High-Performance
• Although about 10 times slower than C coded
applications, Java 1.1 is about twice as Java 1.0
• Common operations like string concatenation are in
native code
• Many interpreter systems include just-in-time compilers
to allow code to run faster on a particular CPU
• Faster than many other interpreted languages and than
most scripting languages like Tcl or Perl
University of Houston-Clear Lake
Multi-Threaded
Software Development
prietary© 1997
Multi-Threaded
• Multiple threads of execution are possible
• Could have audio file playing, image file downloading,
and graphical animation going on simultaneously
• Java syntax support threads directly with synchronized
keyword
• Can easily start threads, stop threads, and assign
priorities
University of Houston-Clear Lake