Sorting ArrayList with Comparitor Interface for String property

[Komari raj]

Hi All

Hi I have list of Beans with 3 proprties of Employee Bean(name, age, address) .

I have Taken Address comparator Class shown in below.

public class AddressComparitor implements Comparator
{ 
public int compare(Bean bean1,Bean bean2)
 { 
int returns=bean1.getAddress().compareTo(bean2.getAddress()); 
return returns;
 } 
} 



ArrayList list=new ArrayList(); 
list.add(new Employee("XXX",25,"12-3-hyd"));
 list.add(new Employee("aaa",56,"AD Road-Delhi")); 
list.add(new Employee("YYY",23,"45-KKD")) ;
list.add(new Employee("bbbb",45,"BRRoad-Delhi")); 

// Sorting.. As per Address which contains Strings or combination of numbers also

Colelctions.sort(list,new AddressComparitor()); 
// Sorting as per Address and display 
System.out.println("...Sorting as per address........"); 
for(int i=0;i <list.size();i++)
{
Employee emp=(Employee)list.get(i);

System.out.println("Address:  "+ emp.getAddress() +" Age: "+ emp.getAge()+"Name: "+emp.getName());
}

Output I am getting is:

Address: 12-3-hyd Age: 25 Name: XXX
Address: 45-KKD Age: 23 Name: YYY
Address: AD Road-Delhi Age: 56 Name: aaa
Address: BRRoad-Delhi Age: 45 Name: bbb


here my requirement is....

I want to display sort beans as per Address like below..

Address: AD Road-Delhi Age: 56 Name: aaa
Address: BRRoad-Delhi Age: 45 Name: bbb
Address: 12-3-hyd Age: 25 Name: XXX
Address: 45-KKD Age: 23 Name: YYY

That comparior Interface is first preference given to numbers only...but i want write comparitor class for giving first preffs to strings...

[Andrey Kozhanov]

Just put necessary functionality in your AddressComparator class. For example if address is a String, it could be written like this:

public class AddressComparator implements Comparator<Bean> {
        public int compare(Bean bean1, Bean bean2) {
            boolean b1Number = Character.isDigit(bean1.getAddress().charAt(0)); // Verifying that first address starts with digit
            boolean b2Number = Character.isDigit(bean2.getAddress().charAt(0)); // Verifying that second address starts with digit

            if (b1Number && !b2Number) {
                return 1;
            } else if (!b1Number && b2Number) {
                return -1;
            } else {
                return bean1.getAddress().compareTo(bean2.getAddress());
            }
        }
    }

[Matthew Brown]

That might work - it depends on what is needed. For instance, that would have 199-XXX come before 1AA-AAA, because it would use alphabetical sorting on the second digit. Whether that is OK depends on the exact requirement (but I suspect it isn't).

[Komari raj]

Andrey Kozhanov wrote:Just put necessary functionality in your AddressComparator class. For example if address is a String, it could be written like this:

public class AddressComparator implements Comparator<Bean> {
        public int compare(Bean bean1, Bean bean2) {
            boolean b1Number = Character.isDigit(bean1.getAddress().charAt(0)); // Verifying that first address starts with digit
            boolean b2Number = Character.isDigit(bean2.getAddress().charAt(0)); // Verifying that second address starts with digit

            if (b1Number && !b2Number) {
                return 1;
            } else if (!b1Number && b2Number) {
                return -1;
            } else {
                return bean1.getAddress().compareTo(bean2.getAddress());
            }
        }
    }

Hi Andrey Kozhanov

Thank you very much..

As my requirement it is ok..

Regards
Raju.Komari