Java development environment and Review of Java

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Java development environment and Review of Java
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EclipseTM Intergrated Development Environment
(IDE)

• Running Eclipse

Warning Never check the Use this as the default
and do not ask again box.
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The importance of workspace

• This is where you will find all your java files.
• You can switch from one workspace to another.
• You need to define the workspace first (where you
  want to put your files) before click on OK

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EclipseTM tutorial
Perspective is a set of related Views (windows)
that enable a development specialist to perform
specific tasks
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Setting up preferences in Eclipse
If you did not download the JDK earlier in this
tutorial, and your existing JRE does not appear
in the Installed JREs preference, you must
add it yourself.
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Setting up preferences in Eclipse
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Setting up preferences in Eclipse
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Create an Eclipse project
From the Eclipse menu bar select File, New,
Project to start the New Project wizard. Select
Java Project and click Next.
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Create an Eclipse project
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Create a Java package

• Structure in dot format
• for example com.tm.tutorial.main

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Create Java classes
Create Application class under com.tm.tutorial.mai
n package
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Create Java classes
Create Application class under com.tm.tutorial.mai
n package
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Implementation of Java class
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Implementation of Java class
Generating setters and getters for attributes
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Implementation of Java class
Generating constructors
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Implementation of Java class
Generating constructors
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Compile Java Application
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Compile Java Application
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Run the application
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Run the application
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Run the application
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Run the application
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Run Application (Shorter way)
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Project 1 discussion
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Algorithm for Main class
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Structure of Report class
-inFile -currentBook, nextBook .
Data members
FileInput
Book
Report object
printReport -processBook -processGenre -columnHea
dings -padL -padR
Methods
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Algorithm for printing a report (Report.java)
Open file
Print footer of the report
processing genre
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Algorithm for process a book and a genre
currentBook record just read Current genre
genre of the current book
Start a new genre and go back to processing a new
genre
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Class exercise

• Class
• Object
• Primitive Data Type
• If, Switch
• While, Do-While

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Review of Java fundamentals
Template for Class Definition
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Review of Java fundamentals
Template for Class Definition
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Numeric data

• Variable declaration
• ltdata typegt ltvariable_namegt
• If more than one variable has the same data type
• ltdata typegt ltname1gt, ltname2gt..

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Six numerical data types

• byte -128 to 127
• short-32768 to 32767 (-215 to 215-1)
• int -231 to 231-1
• long -263 to 263-1
• float -3.4E38 to 3.4E38
• double-1.797E308 to 1.797E308

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Assignment statement

• ltvariable namegt ltexpressiongt
• Example
• x 256-1

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Variable names

• It must be a legal identifier which is an
  unlimited series of characters that begins with a
  letter.
• It must not be a keyword, a boolean literal (true
  or false), or the reserved word null.
• It must be unique within its scope.

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Variable name (cont.)

• Legal identifierbe composed of letters, numbers,
  _ and . Identifiers may only begin with a
  letter, _, or .
• Keyword
• http//java.sun.com/docs/books/tutorial/java/nuts
  andbolts/_keywords.html
• Variable names begin with a lowercase letter
• Class names begin with an uppercase letter

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Constant and variables

• Constant
• Value it contains doesnt change
• final int MONTHS_IN_YEAR 12
• Variables
• Value it contains may vary
• double loanAmount
• loanAmount 0
• loanAmount 1000.99

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Integer division and type casting

• Integer division
• Integer/integer integer, 7/2 3
• Integer/double double, 7/2.0 3.5
• Double/integer double, 7.0/2 3.5
• Type casting a process that converts a value of
  one data type to another data type. Implicit
  casting
• Explicit casting

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Type casting (cont.)

• Implicit casting
• Operand is converted from a lower to a higher
  precision
• Higher precision a data type with a larger range
  of values
• Double has a higher precision than float
• Int has a higher precision than short
• Operand can be a constant, variable, method call
  or another arithmetic expression

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Type casting (cont.)

• Explicit casting
• (ltdata typegt) ltexpressiongt
• Example
• float result
• result (float) ((35)/6)
• and
• result ((float) (53))/6

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Simple Choice Statement
if (ltboolean expressiongt) ltblockgt else
ltblockgt
if (ltboolean expressiongt) single
statement else single statement
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Boolean expression

• Boolean expression is a conditional expression
  that is evaluated to either true or false.
• Conditional expression is a three part
  expression
• ltexp.gt ltrelational operatorsgt ltexp.gt
• Boolean expressions can be combined by boolean
  operators

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Relational Operators
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• Boolean operators
• means AND
• means OR
• ! means NOT

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The While Loop
while(ltboolean expressiongt) // Repeat
multiple statements. statement 1
statement 2 statement 3 ...
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The Do Loop
do // Repeat multiple statements.
statement 1 statement 2 statement 3
... while(ltboolean expression)

• Note that the statements in the body of the loop
  are always executed at least one.
• Note the final semicolon, which is required.

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The For-Loop Outline
// Repeat multiple statements. for(initialization
condition post-body update) // Statements
to be repeated. statement 1 statement 2
statement 3 ...

• Commonly used with increment
• and decrement operators.

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Increment and Decrement

• Used as a shorthand for add-one-to and
  subtract-one-from
• value value1
• value 1
• value
• Prefix and postfix forms
• value
• --value
• value--

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Attributes (Data Member) Declaration
Modifiers
Data Type
Name
private String ownerName
Note Theres only one modifier in this example.
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Method Declaration
Modifier
Return Type
Method Name
Parameter
public void setOwnerName ( String name
) ownerName name
Statements
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Constructor

• A constructor is a special method that is
  executed when a new instance of the class is
  created.

Modifier
Class Name
Parameter
public Bicycle ( ) ownerName
Unassigned
Statements
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Arguments and Parameters

• An argument is a value we pass to a method.
• A parameter is a placeholder in the called method
  to hold the value of the passed argument.

class Account . . . public void
add(double amt) balance balance
amt . . .
class Sample public static void
main(String arg) Account acct
new Account() . . .
acct.add(400) . . . . . .
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Arguments and Parameters

• An argument is a value we pass to a method.
• A parameter is a placeholder in the called method
  to hold the value of the passed argument.

class Account . . . public void
add(double amt) balance balance
amt . . .
class Sample public static void
main(String arg) Account acct
new Account() . . .
acct.add(400) . . . . . .
parameter
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Algorithm for Main class
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Algorithm for printing a report (Report.java)
Open file
Print footer of the report
processing a movie
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Algorithm for process a movie and a genre
currentMovie record just read Current genre
genre of the current movie
Start a new genre and go back to processing a new
genre