Java : Collection Framework : Hashtable (default Constructor CountryCode)

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HashtableExample.java

import java.util.Hashtable;

/*
 * Example of default Hashtable() Constructor.
 */
public class HashtableExample
{
    public static void main( String[] args )
    {

        /*
         * Constructs a new, empty hashtable with a default initial capacity
         * (11) and load factor (0.75).
         */
        Hashtable<String, String> hashtable = new Hashtable<String, String>();

        System.out.println("hashtable : " + hashtable + "\n");

        /*
         * Key = CountryCode,Value = CountryName
         */
        hashtable.put("AF", "AFGHANISTAN");
        hashtable.put("BE", "BELGIUM");
        hashtable.put("US", "UNITED STATES");
        hashtable.put("IN", "INDIA");

        System.out.println("hashtable : " + hashtable);
    }
}

Output

hashtable : {}

hashtable : {IN=INDIA, AF=AFGHANISTAN, BE=BELGIUM, US=UNITED STATES}

To Download HashtableDemoDefaultConsCountryCode Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/HashtableDemoDefaultConsCountryCode.zip?attredirects=0&d=1

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Java : Collection Framework : Hashtable (default Constructor)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=Eg7sbK5WgzY&list=UUhwKlOVR041tngjerWxVccw

HashtableExample.java

import java.util.Hashtable;

/*
 * Example of default Hashtable() Constructor.
 */
public class HashtableExample
{
    public static void main(String[] args)
    {

        /*
         * Constructs a new, empty hashtable with a default initial capacity
         * (11) and load factor (0.75).
         */
        Hashtable<Integer, String> hashtable = new Hashtable<Integer, String>();

        System.out.println("hashtable : " + hashtable + "\n");

        hashtable.put(1, "Apple");
        hashtable.put(2, "Ball");
        hashtable.put(3, "Cat");

        System.out.println("hashtable : " + hashtable);
    }
}

Output

hashtable : {}

hashtable : {3=Cat, 2=Ball, 1=Apple}

To Download HashtableDemoDefaultCons Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/HashtableDemoDefaultCons.zip?attredirects=0&d=1

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JDBC Tutorial

Java : Collection Framework : TreeMap (Comparator - Desc Order CountryCode)

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https://www.youtube.com/watch?v=0N9mOZtGNa0&list=UUhwKlOVR041tngjerWxVccw

DescendingCountryCodeComparator.java

import java.util.Comparator;

public class DescendingCountryCodeComparator implements Comparator<String>
{

    /*
     * This method is used to arrange the CountryCodes in descending order.
     */
    @Override
    public int compare( String countryCode1, String countryCode2 )
    {

        System.out
                .println("\nCompare method has been called in DescendingCountryCodeComparator,

                           \nto arrange"+ " the CountryCodes in decending order : ");

        System.out.println("countryCode1 = " + countryCode1
                + ", countryCode2 = " + countryCode2 + "\n");

        return countryCode2.compareTo(countryCode1);
    }

}

TreeMapExample.java

import java.util.TreeMap;

/*
 * Example of comparator() method.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        DescendingCountryCodeComparator descendingCountryCodeComparator

                                               = new DescendingCountryCodeComparator();

        TreeMap<String, String> treeMap = new TreeMap<String, String>(
                descendingCountryCodeComparator);
        /*
         * Key is CountryCode - Value is CountryName
         */

        System.out.println("Key:CN,Value:CHINA is going to be add in treeMap");
        treeMap.put("CN", "CHINA");
        
        System.out.println("Key:BE,Value:BELGIUM is going to be add in treeMap");
        treeMap.put("BE", "BELGIUM");
        
        System.out.println("Key:AF,Value:AFGHANISTAN is going to be add in treeMap");
        treeMap.put("AF", "AFGHANISTAN");
        
        System.out.println("Key:DK,Value:DENMARK is going to be add in treeMap");
        treeMap.put("DK", "DENMARK");

        System.out.println("treeMap : " + treeMap + "\n");

    }
}

Output

Key:CN,Value:CHINA is going to be add in treeMap

Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = CN, countryCode2 = CN

Key:BE,Value:BELGIUM is going to be add in treeMap

Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = BE, countryCode2 = CN

Key:AF,Value:AFGHANISTAN is going to be add in treeMap

Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = AF, countryCode2 = CN


Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = AF, countryCode2 = BE

Key:DK,Value:DENMARK is going to be add in treeMap

Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = DK, countryCode2 = BE


Compare method has been called in DescendingCountryCodeComparator,
to arrange the CountryCodes in decending order : 
countryCode1 = DK, countryCode2 = CN

treeMap : {DK=DENMARK, CN=CHINA, BE=BELGIUM, AF=AFGHANISTAN}

To Download TreeMapDemoDescOrderCountryCode Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoDescOrderCountryCode.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : TreeMap (Comparator - Asc Order CountryCode)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=B4pwRRIaAaw&list=UUhwKlOVR041tngjerWxVccw

AscendingCountryCodeComparator.java

import java.util.Comparator;

public class AscendingCountryCodeComparator implements Comparator<String>
{

    /*
     * This method is used to arrange the CountryCodes in Ascending order.
     */
    @Override
    public int compare( String countryCode1, String countryCode2 )
    {

        System.out
                .println("\nCompare method has been called in AscendingCountryCodeComparator,

                \nto arrange"+ " the CountryCodes in ascending order : ");

        System.out.println("countryCode1 = " + countryCode1
                + ", countryCode2 = " + countryCode2 + "\n");

        return countryCode1.compareTo(countryCode2);
    }

}

TreeMapExample.java

import java.util.TreeMap;

/*
 * Example of comparator() method.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        AscendingCountryCodeComparator ascendingCountryCodeComparator 

                                          = new AscendingCountryCodeComparator();

        TreeMap<String, String> treeMap = new TreeMap<String, String>(
                ascendingCountryCodeComparator);
        /*
         * Key is CountryCode - Value is CountryName
         */

        System.out.println("Key:CN,Value:CHINA is going to be add in treeMap");
        treeMap.put("CN", "CHINA");
    
        System.out.println("Key:BE,Value:BELGIUM is going to be add in treeMap");
        treeMap.put("BE", "BELGIUM");
        
        System.out.println("Key:AF,Value:AFGHANISTAN is going to be add in treeMap");
        treeMap.put("AF", "AFGHANISTAN");
        
        System.out.println("Key:DK,Value:DENMARK is going to be add in treeMap");
        treeMap.put("DK", "DENMARK");

        System.out.println("treeMap : " + treeMap + "\n");

    }
}

Output

Key:CN,Value:CHINA is going to be add in treeMap

Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = CN, countryCode2 = CN

Key:BE,Value:BELGIUM is going to be add in treeMap

Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = BE, countryCode2 = CN

Key:AF,Value:AFGHANISTAN is going to be add in treeMap

Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = AF, countryCode2 = CN


Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = AF, countryCode2 = BE

Key:DK,Value:DENMARK is going to be add in treeMap

Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = DK, countryCode2 = BE


Compare method has been called in AscendingCountryCodeComparator,
to arrange the CountryCodes in ascending order : 
countryCode1 = DK, countryCode2 = CN

treeMap : {AF=AFGHANISTAN, BE=BELGIUM, CN=CHINA, DK=DENMARK}

To Download TreeMapDemoAscOrderCountryCode Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoAscOrderCountryCode.zip?attredirects=0&d=1

See also:

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All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection : TreeMap (Ascending and Descending Order Sample Program) - Playlist

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https://www.youtube.com/watch?v=hBaoCkE5Zks&list=PLmCsXDGbJHdhzXUh1nzS6128rk_wzy7pB

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All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : TreeMap (Comparator)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=pPIQIlLPVOo&list=UUhwKlOVR041tngjerWxVccw

DescendingEmployeeIdComparator.java

import java.util.Comparator;

public class DescendingEmployeeIdComparator implements Comparator<Integer>
{

    /*
     * This method used to arrange the employeeId's in descending order.
     */
    @Override
    public int compare( Integer empId1, Integer empId2 )
    {

        if( empId1 < empId2 )
        {

            return 1;
        }
        else
        {
            return -1;
        }
    }

}

TreeMapExample.java

import java.util.Comparator;
import java.util.TreeMap;

/*
 * Example of comparator() method.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        DescendingEmployeeIdComparator descendingEmployeeIdComparator 

                                              = new DescendingEmployeeIdComparator();

        TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>(
                descendingEmployeeIdComparator);
        /*
         * Key is EmployeeId - Value is EmployeeName
         */

        treeMap.put(20, "Balu");
        treeMap.put(10, "Ajay");
        treeMap.put(40, "Carol");
        treeMap.put(30, "Dave");

        System.out.println("treeMap : " + treeMap + "\n");
        
        Comparator<?> comparator = treeMap.comparator();
        
        System.out.println("Comparator name : "+comparator.getClass().getName());

    }
}

Output

treeMap : {40=Carol, 30=Dave, 20=Balu, 10=Ajay}

Comparator name : DescendingEmployeeIdComparator

To Download DisplayAllHeadersApp Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoComparator.zip?attredirects=0&d=1

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All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : TreeMap (Comparator - Desc Order EmployeeId)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=ty8GK1fCzrQ&list=UUhwKlOVR041tngjerWxVccw

DescendingEmpIoyeeIdComparator.java

import java.util.Comparator;

public class DescendingEmpIoyeeIdComparator implements Comparator<Integer>
{

    /*
     * This method used to arrange the employeeId's in descending order.
     */
    @Override
    public int compare( Integer employeeId1, Integer employeeId2 )
    {

        System.out
                .println("\nCompare method has been called in 

                   DescendingEmpIoyeeIdComparator, \nto arrange"
                        + " the employeeId's in descending order : ");

        System.out
                .println("employeeId1 = " + employeeId1 + ", employeeId2 = " + employeeId2 + "\n");

        if( employeeId1 < employeeId2 )
        {
            
            return 1;
        }
        else
        {
            return -1;
        }
    }

}

TreeMapExample.java

import java.util.TreeMap;

/*
 * Example of TreeMap(Comparator<? super K> comparator) Constructor.
 */
public class TreeMapExample
{
    public static void main(String[] args)
    {

        DescendingEmpIoyeeIdComparator descendingEmpIoyeeIdComparator 

                                                   = new DescendingEmpIoyeeIdComparator();

        TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>(
                descendingEmpIoyeeIdComparator);
        /*
         * Key is EmployeeId - Value is EmployeeName
         */

        System.out.println("Key:20,Value:Balu is going to be add in treeMap");
        treeMap.put(20, "Balu");

        System.out.println("Key:10,Value:Ajay is going to be add in treeMap");
        treeMap.put(10, "Ajay");

        System.out.println("Key:40,Value:Carol is going to be add in treeMap");
        treeMap.put(40, "Carol");

        System.out.println("Key:30,Value:Dave is going to be add in treeMap");
        treeMap.put(30, "Dave");

        System.out.println("treeMap : " + treeMap + "\n");

    }
}

Output

Key:20,Value:Balu is going to be add in treeMap

Compare method has been called in DescendingEmpIoyeeIdComparator, 
to arrange the employeeId's in descending order : 
employeeId1 = 20, employeeId2 = 20

Key:10,Value:Ajay is going to be add in treeMap

Compare method has been called in DescendingEmpIoyeeIdComparator, 
to arrange the employeeId's in descending order : 
employeeId1 = 10, employeeId2 = 20

Key:40,Value:Carol is going to be add in treeMap

Compare method has been called in DescendingEmpIoyeeIdComparator, 
to arrange the employeeId's in descending order : 
employeeId1 = 40, employeeId2 = 20

Key:30,Value:Dave is going to be add in treeMap

Compare method has been called in DescendingEmpIoyeeIdComparator, 
to arrange the employeeId's in descending order : 
employeeId1 = 30, employeeId2 = 20


Compare method has been called in DescendingEmpIoyeeIdComparator, 
to arrange the employeeId's in descending order : 
employeeId1 = 30, employeeId2 = 40

treeMap : {40=Carol, 30=Dave, 20=Balu, 10=Ajay}

To Download TreeMapDemoDescOrderEmpId Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoDescOrderEmpId.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : TreeMap (Comparator - Asc Order EmployeeId)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=hBaoCkE5Zks&list=UUhwKlOVR041tngjerWxVccw

AscendingEmployeeIdComparator.java

import java.util.Comparator;

public class AscendingEmployeeIdComparator implements Comparator<Integer>
{

    /*
     * This method used to arrange the employeeId's in ascending order.
     */
    @Override
    public int compare( Integer employeeId1, Integer employeeId2 )
    {

        System.out
                .print("Compare method has been called in AscendingEmployeeIdComparator,\nto arrange"
                        + " the EmpId's in ascending order : ");

        System.out
                .println("employeeId1 = " + employeeId1 + ", employeeId2 = " + employeeId2 + "\n");

        if( employeeId1 < employeeId2 )
        {
            return -1;
        }
        else
        {
            return 1;
        }
    }

}

TreeMapExample.java

import java.util.TreeMap;

/*
 * Example of TreeMap(Comparator<? super K> comparator) Constructor.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        AscendingEmployeeIdComparator ascendingEmployeeIdComparator 

                                                 = new AscendingEmployeeIdComparator();

        TreeMap<Integer, String> treeMap = new TreeMap<Integer, String>(
                ascendingEmployeeIdComparator);
        /*
         * Key is EmployeeId - Value is EmployeeName
         */
        
        System.out.println("Key:20,Value:Balu is going to be add in treeMap.");
        treeMap.put(20, "Balu");
        
        System.out.println("Key:10,Value:Ajay is going to be add in treeMap.");
        treeMap.put(10, "Ajay");
        
        System.out.println("Key:40,Value:Carol is going to be add in treeMap.");
        treeMap.put(40, "Carol");
        
        System.out.println("Key:30,Value:Dave is going to be add in treeMap.");
        treeMap.put(30, "Dave");

        System.out.println("treeMap : " + treeMap + "\n");

    }
}

Output

Key:20,Value:Balu is going to be add in treeMap.
Compare method has been called in AscendingEmployeeIdComparator,
to arrange the EmpId's in ascending order : employeeId1 = 20, employeeId2 = 20

Key:10,Value:Ajay is going to be add in treeMap.
Compare method has been called in AscendingEmployeeIdComparator,
to arrange the EmpId's in ascending order : employeeId1 = 10, employeeId2 = 20

Key:40,Value:Carol is going to be add in treeMap.
Compare method has been called in AscendingEmployeeIdComparator,
to arrange the EmpId's in ascending order : employeeId1 = 40, employeeId2 = 20

Key:30,Value:Dave is going to be add in treeMap.
Compare method has been called in AscendingEmployeeIdComparator,
to arrange the EmpId's in ascending order : employeeId1 = 30, employeeId2 = 20

Compare method has been called in AscendingEmployeeIdComparator,
to arrange the EmpId's in ascending order : employeeId1 = 30, employeeId2 = 40

treeMap : {10=Ajay, 20=Balu, 30=Dave, 40=Carol}

To Download TreeMapDemoAscOrderEmpId Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoAscOrderEmpId.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : LinkedHashMap (Add User-Defined Object)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=8XpccS80VuM&list=UUhwKlOVR041tngjerWxVccw

Employee.java

public class Employee
{

    private String name;
    private int    age;
    private int    salary;

    public Employee( String name, int age, int salary )
    {
        super();
        this.name = name;
        this.age = age;
        this.salary = salary;
    }

    public String getName()
    {
        return name;
    }

    public void setName( String name )
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge( int age )
    {
        this.age = age;
    }

    public int getSalary()
    {
        return salary;
    }

    public void setSalary( int salary )
    {
        this.salary = salary;
    }

    @Override
    public String toString()
    {
        return "Employee [name=" + name + ", age=" + age + ", salary=" + salary
                + "]";
    }

}

LinkedHashMapExample.java

import java.util.Map;
import java.util.Set;
import java.util.LinkedHashMap;

/*
 * Example of adding User defined Object.
 */
public class LinkedHashMapExample
{
    public static void main(String[] args)
    {

        LinkedHashMap<Integer, Employee> linkedHashMap = new LinkedHashMap<Integer, Employee>();

        Employee john = new Employee("John", 32, 40000);
        Employee david = new Employee("David", 42, 80000);
        Employee peter = new Employee("Peter", 52, 150000);

        /*
         * Key is EmpId - Value is Employee Object
         */

        linkedHashMap.put(20, john);
        linkedHashMap.put(10, david);
        linkedHashMap.put(40, peter);

        System.out.println("linkedHashMap : " + linkedHashMap + "\n");

        Set<Map.Entry<Integer, Employee>> set = linkedHashMap.entrySet();

        System.out.println("set : " + set + "\n");

        System.out.println("-----------------------");
        System.out.println("Key" + " | " + "value");
        System.out.println("-----------------------");

        for (Map.Entry<Integer, Employee> entry : set)
        {
            int empId = entry.getKey();
            Employee employee = entry.getValue();
            System.out.println(empId + "   | " + employee);
        }

    }
}

Output

linkedHashMap : {20=Employee [name=John, age=32, salary=40000], 10=Employee [name=David, age=42, salary=80000], 40=Employee [name=Peter, age=52, salary=150000]}

set : [20=Employee [name=John, age=32, salary=40000], 10=Employee [name=David, age=42, salary=80000], 40=Employee [name=Peter, age=52, salary=150000]]

-----------------------
Key | value
-----------------------
20   | Employee [name=John, age=32, salary=40000]
10   | Employee [name=David, age=42, salary=80000]
40   | Employee [name=Peter, age=52, salary=150000]

To Download LinkedHashMapDemoUserDefined Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/LinkedHashMapDemoUserDefined.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : HashMap (Add User-Defined Object)

Click here to watch in Youtube : 
https://www.youtube.com/watch?v=Z1MIdaZ0vEM&list=UUhwKlOVR041tngjerWxVccw

Employee.java

public class Employee
{

    private String name;
    private int    age;
    private int    salary;

    public Employee( String name, int age, int salary )
    {
        super();
        this.name = name;
        this.age = age;
        this.salary = salary;
    }

    public String getName()
    {
        return name;
    }

    public void setName( String name )
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge( int age )
    {
        this.age = age;
    }

    public int getSalary()
    {
        return salary;
    }

    public void setSalary( int salary )
    {
        this.salary = salary;
    }

    @Override
    public String toString()
    {
        return "Employee [name=" + name + ", age=" + age + ", salary=" + salary
                + "]";
    }

}

HashMapExample.java

import java.util.Map;
import java.util.Set;
import java.util.HashMap;

/*
 * Example of adding User defined Object.
 */
public class HashMapExample
{
    public static void main(String[] args)
    {

        HashMap<Integer, Employee> hashMap = new HashMap<Integer, Employee>();

        /*
         * Key is EmpId - Value is Employee Object
         */

        Employee john = new Employee("John", 32, 40000);
        Employee david = new Employee("David", 42, 80000);
        Employee peter = new Employee("Peter", 52, 150000);

        hashMap.put(20, john);
        hashMap.put(10, david);
        hashMap.put(40, peter);

        System.out.println("hashMap : " + hashMap + "\n");

        Set<Map.Entry<Integer, Employee>> set = hashMap.entrySet();

        System.out.println("set : " + set + "\n");

        System.out.println("-----------------------");
        System.out.println("Key" + " | " + "value");
        System.out.println("-----------------------");

        for (Map.Entry<Integer, Employee> entry : set)
        {
            int empId = entry.getKey();
            Employee employee = entry.getValue();
            System.out.println(empId + "   | " + employee);
        }

    }
}

Output

hashMap : {20=Employee [name=John, age=32, salary=40000], 40=Employee [name=Peter, age=52, salary=150000], 10=Employee [name=David, age=42, salary=80000]}

set : [20=Employee [name=John, age=32, salary=40000], 40=Employee [name=Peter, age=52, salary=150000], 10=Employee [name=David, age=42, salary=80000]]

-----------------------
Key | value
-----------------------
20   | Employee [name=John, age=32, salary=40000]
40   | Employee [name=Peter, age=52, salary=150000]
10   | Employee [name=David, age=42, salary=80000]

To Download HashMapDemoUserDefined Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/HashMapDemoUserDefined.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

All JavaEE Viedos

Servlets Tutorial

All Design Patterns Links

JDBC Tutorial

Java : Collection Framework : TreeMap (Add User-Defined Object)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=KsPY3o22Gww&list=UUhwKlOVR041tngjerWxVccw

Employee.java

public class Employee
{

    private String name;
    private int    age;
    private int    salary;

    public Employee( String name, int age, int salary )
    {
        super();
        this.name = name;
        this.age = age;
        this.salary = salary;
    }

    public String getName()
    {
        return name;
    }

    public void setName( String name )
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge( int age )
    {
        this.age = age;
    }

    public int getSalary()
    {
        return salary;
    }

    public void setSalary( int salary )
    {
        this.salary = salary;
    }

    @Override
    public String toString()
    {
        return "Employee [name=" + name + ", age=" + age + ", salary=" + salary
                + "]";
    }

}

TreeMapExample.java

import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

/*
 * Example of adding User defined Object.
 */
public class TreeMapExample
{
    public static void main( String[] args )
    {

        TreeMap<Integer, Employee> treeMap = new TreeMap<Integer, Employee>();

        Employee john = new Employee("John", 32, 40000);
        Employee david = new Employee("David", 42, 80000);
        Employee peter = new Employee("Peter", 52, 150000);

        /*
         * Key is EmpId - Value is Employee Object
         */
        treeMap.put(20, john);
        treeMap.put(10, david);
        treeMap.put(40, peter);

        System.out.println("treeMap : " + treeMap + "\n");

        Set<Map.Entry<Integer, Employee>> set = treeMap.entrySet();

        System.out.println("set : " + set + "\n");

        System.out.println("-----------------------");
        System.out.println("Key" + " | " + "value");
        System.out.println("-----------------------");

        for( Map.Entry<Integer, Employee> entry : set )
        {
            int empId = entry.getKey();
            Employee employee = entry.getValue();
            System.out.println(empId + "   | " + employee);
        }

    }
}

Output

treeMap : {10=Employee [name=David, age=42, salary=80000], 20=Employee [name=John, age=32, salary=40000], 40=Employee [name=Peter, age=52, salary=150000]}

set : [10=Employee [name=David, age=42, salary=80000], 20=Employee [name=John, age=32, salary=40000], 40=Employee [name=Peter, age=52, salary=150000]]

-----------------------
Key | value
-----------------------
10   | Employee [name=David, age=42, salary=80000]
20   | Employee [name=John, age=32, salary=40000]
40   | Employee [name=Peter, age=52, salary=150000]

To Download TreeMapDemoUserDefined Project Click the below link
https://sites.google.com/site/javaee4321/java-collections/TreeMapDemoUserDefined.zip?attredirects=0&d=1

See also:

All JavaEE Viedos Playlist

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Servlets Tutorial

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