Object Oriented Programming Traits in Groovy Scripting groovy training telugu 40

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//Bird.groovy

package com.theraldanvega.traits

class Bird implements FlyingAbility, SpeakingAbility{

}

//FlyingAbility.groovy

package com.theraldanvega.traits

trait FlyingAbility{

String fly(){

'I am Fly'

}

}

//SpeakingAbility.groovy

package com.therealdanvega.traits

trait SpeakingAbility

{

trait SpeakingAbility{

 String speak(){

"I am Speaking"

}

}

//App.groovy

package com.therealdanvega

import com.therealdanvega.traits.Bird

Bird b=new Bird()

assert b.fly()== "I am Flying"

assert b.speak() =="I am Speaking"

Object Oriented Programming Interface in Groovy Scripting groovy training telugu 39

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//Person.groovy

package com.therealdanvega.domain

@groovy.transform.ToString()

class Person{

String first, last

}

//IPersonService.groovy

package com.therealdanvega.service

import com.therealdanvega.domain.Person

interface IPersonService{

Person find()

List <People> findAll()

}

//PersonService.groovy

package com.therealdanvega.service

import com.therealdanvega.domain.Person

class PersonService implements IPersonService{

@Override

Person find(){

person p= new Person(first:"Dan",last:"vega")

return p

}

@Override

List <People> findAll(){

person p1= new Person(first:"Dan",last:"vega")

person p2= new Person(first:"jam",last:"vega")

[p1,p2]

}

}

//App.groovy

package com.therealdanvega

import com.therealdanvega.service.PersonService

PersonService ps=new PersonService()

println ps.find()

 

Object Oriented Programming Inheritance in Groovy Scripting groovy training telugu 38

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// Phone.groovy

package com.therealdanvega.domain

class Phone{

String name

String os

String appStore

def powerOn(){

}

def powerOff(){

}

def ring(){

}

}

//Iphone.groovy

package com.therealdanvega.domain

@groovy.transform.ToString

class Iphone extends Phone{

String iosVersion

def homeButtonPressed(){

}

def airplay(){

}

def powerOn()

{

}

}

//App.groovy

package com.therealdanvega

package com.therealdanvega.domain.Iphone

Iphone phone = new Iphone(name:"iphone",appStore:"Apple Store",os:"ios")

println phone

Object Oriented Programming Organizing Classes into Packages in Groovy Scripting training intelugu37

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Object Oriented Programming Constructors & Methods in Groovy Scripting training telugu 36

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@groovy.transform.ToString

class Person{

String first,last

//Constractor

Person(String fullName){

List parts =fullName.split(' ')

this.first=parts[0]

this.first=parts[1]

}

//methods

public void foo(String a, String b){

//do stuff

}

String getFullName(){

"$last $first"

}

def bar(){

}

ststic String doGoodWork(){

println "do some good work............"

}

List someMethod (List num=[1,,2,3] Boolean canAccessAll=false){

}

}

/*Person p= new Person ("Dan Vega")

println p */

Person.doGoodWork()

Object Oriented Programming Classes Fields Local Variables in groovy Scripting groovy training telugu 35

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class Person{

String firstName,lastName

def dob

//private |  protected |public

protected String f1,f2,f3

private Date createdOn= new Date()

static welcomeMsg="Hello"

public static final String WELCOME_MSG="HELLO"

}

//LOCAL VARIABLES

def foo(){

String msg ="Hello"

String firstName="Dan"

println"$msg, $firstName"

}

}

def Person =new Person()

println Person.foo()

 

Exercise UsingControl Structures Groovy Scripting in groovy traing telugu 34

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[Exercise] Control Structures

Control Structures

We used a class similar to this in a previous exercise but I think it's a short and sweet example of what we need to review in this exercise. 

Create An Account Class

create a property of type BigDecimal called balance with an initial value of 0.0

Create a method called deposit

use a conditional structure (if would work great here) to check if the amount being passed is less than zero. If it is we should catch this case because we don't want to deposit negative numbers. In this case, throw an exception.

Create another method called deposit that takes a list of amounts

use a for loop to loop over these amounts and call deposit

Now that we have our class let's test it out. You can do all of this in the same file (just don't create a file called Account.groovy) 

Create an instance of the account class

deposit a valid amount

deposit an invalid amount (what happens?)

try / catch on invalid amounts

deposit a list of amounts. 

//CODE

class Account {

BigDecimal balance=0.0

def deposit(BigDecimal amount)

{

if(amount <0){

throw new Exception("Deposit amoubt must be greater than 0")

}

balance += amount

}

def deposit(List amounts){

for (amount in amounts){

deposit(amount)

}

}

}

Account checking =new Account()

checking.deposit(10.00)

println checking.blance

try{

checking.deposit(-2)

}

catch(Exception e)

{

println "You entet invalid amount"

}

println checking.blance

ExceptionHandling in Groovy Scripting grrovy training in telugu 33

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def foo(){

//do stuff

throw new Exception("Foo Exception")

}

List log=[]

try{

foo()

}

catch(Exception e){

log <<e.message

}

finally{

log <<'finally'

}

println log

//Java 7 version multiple catch block

try{

//do something

}

catch (FileNotFoundException | NullPointerException)

{

println e.class.name

println e.message

}

Looping in Groovy Scripting groovy training telugu 32

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//Looping

//while

List numbers=[1,2,3]

while(numbers)

{

//do something

numbers.remove(0)

}

assert numbers ==[]

//for

List nums=[1,2,3,4]

for(Integer i in 1..10){

println i

}

for(j in 1..5)

{

println j

}

Conditional Structure in Groovy Scripting groovy training telugu 31

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// if boolean (expression) {// logic}

if (true){

println true

}

if (true)

println true

def age=35

if (age>=35){

println "can run president"

}

if (false){

println true

}

else {

println false

}

def yourage=18

if(yourage>=21){

println"eligible for Marriage"

}

else{

println "not eligible for Marriage"

}

def someage=37

if(someage>= 21 && someage <35){

println "eligible for Marriage"

}

else if(someage >= 35){

println "run for president"

}

else {

println "not eligible for Marriage"

}

// ternary operator

def name='Dan'

def isitdan=(name.toUpperCase()=='DAN')?'YES":'NO'

println isitdan

//switch

def num=5

switch(num){

case 1:

println "1"

case 2:

println "2"

default:

println "default value"

}

Groovy Truth in Groovy Scripting groovy training telugu 30

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// Boolean

assert true

assert !false

//matcher

assert ('a'=='a')

assert !('a'=='b')

//collection

assert [1]

assert ![]

//map

assert [1:'one']

assert ![:]

//String

assert "asd"

assert !""

//Number

assert 1

assert 3.5

assert !0

//None of the above

assert new Object()

assert null

Exercise Using Closure in Groovy Scripting groovy traing telugu 29

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[Exercise] Using Closures

Closure Basics

Locate the class groovy.lang.Closure and spend a few minutes looking through documentation.

Create a Method that accepts a closure as an argument

Create a closure that performs some action

Call the method and pass the closure to it.

Create a list and use them each to iterate over each item in the list and print it out

Hint - You can use the implicit it or use your own variable

Create a map of data and iterate over it using each method. 

This method can take a closure that accepts 1 or 2 arguments. 

Use 2 arguments and print out the key and value on each line.

Demonstrate the use of curry and try to come up with an example different from the one we used in the lecture. 

Explore the GDK

In the following exercises we are going to explore the GDK to find some methods that take closures and learn how to use them. Hint - I would narrow your search to java.util.Collection, java.lang.Iterable & java.util.List

Search for the find and findAll methods.

What is the difference between the two? 

Write some code to show how they both work.

Search for the any and every methods.

What is the difference between the two? 

Write some code to show how they both work. 

Search for the method groupBy that accepts a closure

What does this method do? 

Write an example of how to use this method.

def mymethod(Closure c){

c()

}

def foo={

println"foooo..............."

}

mymethod(foo)

List names=["Dan","Vega","Jhon","rashmi","rasi"]

names.each{name ->

 println name

}

Map teams=[baseball:"Cleveland Indians", basketball:"Cleveland Cavs", football:"Cleveland Browns"]

teams.each{k,v ->

println"$k=$v"

}

def greet ={ String greeting, String name ->

println "$greeting,$name"

}

greet ("HELLO","DAN")

def sayHello=greet.curry("HELLO")

List people=[

[name:"Jame", city:"New York City"]

[name:"Jhon", city:"Cleveland"]

[name:"Mary", city:"New York City"]

[name:"Dan", city:"Cleveland"]

[name:"Ton", city:"New York City"]

[name:"Frank", city:"New York City"]

[name:"Jason", city:"Cleveland"]

]

println people.find{person ->person.city=="Cleveland"}

println people.findAll{person ->person.city=="Cleveland"}

println people.any{person ->person.city=="Cleveland"}

println people.every{person ->person.city=="Cleveland"}

def peopleByCity =people.groupBy{person ->person.city}

println peopleByCity

Scope of Delegate in Groovy Scripting groovy trainig telugu 28

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class ScopeDemo{

def outerClosure ={

println this.class.name

println owner.class.name

println delegate.class.name

def innerClosure={

println this.class.name

println owner.class.name

println delegate.class.name

}

innerClosure()

}

}

def demo=new ScopeDemo()

//other Example

def writer={

append 'Dan'

append 'lives in USA'

}

def append(String s){

println "append() called with argument of $s"

}

StringBuffer sb= new StringBuffer()

writer.resolveStrategy=Closure.DELEGATE_FIRST

writer.delegate=sb

writer()

Curry Methods in Groovy Scripting groovy training telugu 27

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def log={String type,Date createdOn,String  msg ->

println"$createdOn [$type]-$mgs"

}

log("DEBUG", new Date(),"This is my first debug statement......")

def debuglog =log.curry("DEBUG")

debuglog(new Date(),"This is my first debug statement.........")

debuglog(new Date(),"This is onOther")

def todayDebugLog= log.curry("DEBUG",new Date())

todayDebugLog("This is today Bug")

//right curry

def crazyPersonLog =log.rcurry("Why i am logging this way")

crazyPersonLog("ERROR",new Date())

//index based Curring

def typeMsgLog=log.ncurry(1,new Date())

typeMsgLog("ERROR","This is using ncurry")

Collection Methods in Groovy Scripting groovy scripting training telugu 26

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//each &eachWithIndex

List nums =[2,21,44,35,8,4]

for (i in nums){

println i

}

nums.each{println it}

for (int j=0;j<nums.size();j++){

println "$j:${nums[j]}"

}

nums.eachWithIndex{num.idx ->

println "$idx:$num"

}

//findAll

List days=["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"]

List weekend=days.findAll{it.startsWith("S")}

println days

println weekend

//collect

List number=[3,6,7,9,8]

List numsTimesTen=[]

number.each{num ->

numsTimesTen << num*10

}

List newTimesTen = number.collect{ num -> num*10}

println number

println numsTimesTen

println newTimesTen

Closures Parameters in Groovy Scripting groovy training telugu 25

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//implict parameter

def foo={

println it

}

foo('don')

def noparass={->

println "no parss...."

}

noparass()

def sayHello ={String first, String last ->

println "Hello, $first $last"

}

sayHello("Dan","vega")

// Default values

def greet={String name, String greeting ="Howdy"->

println "$greeting,$name"

}

greet ("Dan","Hello")

greet("vega")

//var-arg

def concat={String...args->

agrs.join('')

}

println concat('abc','def')

println concat('abc','def','gfd')

Creating Closures in Groovy Scripting groovy training telugu 24

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def c ={}

println c.class.name

println c instanceof Closure

def sayHelo={ name ->

println "Hello $name"

}

sayHello('rashmi')

List num=[3,4,5,6,7]

num.each({ nums ->

println nums

})

//closures are object

def timesTen(num,closure){

 closure{num *10}

}

timesTen(10,{println it})

timesTen(2,{println it})

Clousers in Groovy Scripting groovy training telugu 23

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http://groovy-lang.org/closures.html

Closures:

This chapter covers Groovy Closures. A closure in Groovy is an open,

anonymous, block of code that can take arguments, return a value 

and be assigned to a variable. A closure may reference variables 

declared in its surrounding scope. In opposition to the formal 

definition of a closure, Closure in the Groovy language can also 

contain free variables which are defined outside of its surrounding scope.

While breaking the formal concept of a closure, it offers a variety of 

advantages which are described in this chapter.

Syntax:

{ [closureParameters -> ] statements }

Exercise Collections in Groovy Scripting groovy training telugu 22

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[Exercise] Using Collections

1)Ranges

If you are new to Java or Groovy the idea of an Enum might be new. An Enum is a collection of constant values. We can use this collection of constants to create ranges. I want you to do some reading up on enum's and create an enum for days of the week. ex Sunday, Monday, etc...

Create a range from that enum

Print the size of the Range

Use the contains method to see if Wednesday is in that Range

Print the from element of this range

Print the to element of this range

2)Lists

Create a list days (Sun - Sat)

Print out the list

Print the size of the list

Remove Saturday from the list

Add Saturday back by appending it to the list

Print out the Wednesday using its index

3)Maps

Create a map of days of the week

1: Sunday, 2:Monday, etc...

Print out the map

Print out the class name of the map

Print the size of the map

Is there a method that would easily print out all of the days (values)? 

Without closures you may have to look at the Java API for LinkedHashMap

//Range

enum Days{

SUNDAY,MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY

}

def dayRange=Days.SUNDAY..days.SATURDAY

//for in loop

for(day in dayRange){

println day

}

// using Closures

dayRange.each{day ->

println day

}

println dayRange.size()

println dayRange.contains(Days.WEDNESDAY)

println dayRange.from

println dayRange.to

//List

def days = ["SUNDAY","MONDAY","TUESDAY","WEDNESDAY","THURSDAY","FRIDAY","SATURDAY"]

println days

println days.size()

days.pop()

println days

days<<"Sunday"

println days

println days[2]

//Map

def days = [1:"SUNDAY",2:"MONDAY",3:"TUESDAY",4:"WEDNESDAY",5:"THURSDAY",6:"FRIDAY",7:"SATURDAY"]

println days

println days.getClass().getName()

println days.size()

println days.values()

Collections Map in GroovyScripting groovy training in telugu 21

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Map map=[:]

println map

println map.getClass().getName()

def person =[first:"ravi",email:"ravikuamr@email.com"]

println person

println person.first

person.twiter="qdfefefregre"

println person

def emailkey="emailadress"

def whatsapp=[name:"rashmi", (emailkey):"uiwhdiuhi@email.com"]

println(whatsapp)

println person.size()