How Can ArrayList Created on if Condition dynamically be accessed on Else Condition?

Question

I have listed the Data, ie name,gender,dept, in a List. I have added the data with different department like QA, Java, Php in the List. Now I have to put the Data with Specific Department in the hashmap (eg all the QA department should be listed on one ArrayList or List dynamically). If I add the new department then it should be Listed in a new ArrayList dynamically, not by hard coding. It is simple logic but I am not able to solve this.

Getter and Setter

public class Employ {

    private String name;
    private int id;
    private String gender;
    private String dept;

    public Employ(String name,int id,String gender,String dept){
        this.name=name;
        this.id=id;
        this.gender=gender;
        this.dept=dept;

    }     

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the id
     */
    public int getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public void setId(int id) {
        this.id = id;
    }

    /**
     * @return the gender
     */
    public String getGender() {
        return gender;
    }

    /**
     * @param gender the gender to set
     */
    public void setGender(String gender) {
        this.gender = gender;
    }

    /**
     * @return the dept
     */
    public String getDept() {
        return dept;
    }

    /**
     * @param dept the dept to set
     */
    public void setDept(String dept) {
        this.dept = dept;
    }
}

Main Class

public class App {

    public static void main(String[] args) {
        String key="QA";
        String key2="java";
        HashMap<String ,List<Employ>> soft=new HashMap();

        List<Employ> employList=new ArrayList();
        employList.add(new Employ("ram",1, "male","qa"));
        employList.add(new Employ("tom",2, "male","qa"));
        employList.add(new Employ("arjun",3, "male","java"));
        employList.add(new Employ("hari",4, "male","java"));
        employList.add(new Employ("kumar",5, "male","qa"));
        employList.add(new Employ("sita",6, "female","java"));
        employList.add(new Employ("rajan",7, "female","qa"));
        employList.add(new Employ("rajal",8, "female","php"));

        for(Employ emp:employList){  
            if(!soft.containsKey(emp.getDept())){
                soft.put(emp.getDept(),new ArrayList());
            }else{
                // soft.put(emp.getDept(),add("qa"));
            }
        }
    }
}

How can this be achieved?

Answer 1

If I understand correctly, you want to group employees by department.

The imperative way would be

for (Employee employee: employeeList){  
    List<Employee> departmentList = f1soft.get(employee.getDepartment());
    if (departmentList == null) {
        departmentList = new ArrayList<>();
        f1soft.put(emp.getDepartment(), departmentList);
    }
    departmentList.add(employee);
}

Or, simpler:

for (Employee employee: employeeList){  
    f1soft.computeIfAbsent(department, d -> new ArrayList<Employee>()).add(employee);
}

But it's must simpler to do that with streams:

Map<String, Employee> f1soft = 
    employeeList.stream()
                .collect(Collectors.groupingBy(Employee::getDepartment)); 

Note that I choose to rename your types and properties to make everything more readable. There's really no good reason to use Employ instead of Employee, or Dept instead of Department.

Answer 2

If the key emp.getDept() is present in the Map , you can obtain the corresponding ArrayList value with f1soft.get(emp.getDept()) and add whatever you wish to it.

for(Employ emp : employList){  
    if (!soft.containsKey(emp.getDept())) {
        soft.put(emp.getDept(),new ArrayList());
    }
    soft.get(emp.getDept()).add(emp);
}

BTW, this loop can be replaced with the following Java 8 code:

Map<String ,List<Employ>> soft = 
    employList.stream().collect(Collectors.groupingBy(Employ::getDept));