Sort a Java collection object based on one field in it

Question

I have the following collection:

Collection<AgentSummaryDTO> agentDtoList = new ArrayList<AgentSummaryDTO>(); 

Where AgentSummaryDTO looks like this:

public class AgentSummaryDTO implements Serializable {     private Long id;     private String agentName;     private String agentCode;     private String status;     private Date createdDate;     private Integer customerCount; } 

Now I have to sort the collection agentDtoList based on the customerCount field, how to achieve this?

Answer 1

here is my "1liner":

Collections.sort(agentDtoList, new Comparator<AgentSummaryDTO>(){    public int compare(AgentSummaryDTO o1, AgentSummaryDTO o2){       return o1.getCustomerCount() - o2.getCustomerCount();    } }); 

UPDATE for Java 8: For int datatype

 Collections.sort(agentDtoList, (o1, o2) -> o1.getCustomerCount() - o2.getCustomerCount()); 

or even:

 Collections.sort(agentDtoList, Comparator.comparing(AgentSummaryDTO::getCustomerCount)); 

For String datatype (as in comment)

Collections.sort(list, (o1, o2) -> (o1.getAgentName().compareTo(o2.getAgentName()))); 

..it expects getter AgentSummaryDTO.getCustomerCount()