CODEWITHSUNDEEP
javaarrayslistsearcharraylist
Yasir Shabbir Choudhary
Yasir Shabbir Choudhary

Reputation: 2578

How to check Object ArrayList contain single attribute of Object without Loop

Here is the answer of this question but I need is there any other way

Let Suppose Person is a class contains attribute

An ArrayList hold thousand person object ,I want to check that "11" personId is in ArayList or not?

One way is to iterate(Loop) arraylist and check single by single.

Is there any other way to resolve this?

Upvotes: 3

Views: 2006

Answers (2)

Sireesh Vattikuti
Sireesh Vattikuti

Reputation: 1190

Override equals() and hashcode() method in your POJO for person Id

eg:

import java.util.ArrayList;

public class Test {
private int personId;
private String name;
//getters and Setters



@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + personId;
    return result;
}
@Override
public boolean equals(Object obj) {
    if (this == obj)
       return true;
    if (obj == null)
       return false;
    if (getClass() != obj.getClass())
       return false;
    Test other = (Test) obj;
    if (personId != other.personId)
       return false;
    return true;
}
public static void main(String[] args) {
    ArrayList<Test> test=new ArrayList<Test>();

Test t=new Test();
t.setName("Sireesh");
t.setPersonId(1);

Test t1=new Test();
t1.setName("Ramesh");
t1.setPersonId(2);

Test t2=new Test();
t2.setName("Rajesh");
t2.setPersonId(3);


test.add(t);
test.add(t1);
test.add(t2);

Test tx=new Test();
tx.setPersonId(1);
System.out.println(test.contains(tx));
//Returns true

}
}

Upvotes: 5

Adisesha
Adisesha

Reputation: 5258

Implement equals and hashCode based on persionId. java.util.ArrayList#contains will give you results. This solution is as good as looping through list and finding the object.

Upvotes: 1

Related Questions