java - Sorting List in pairs without using Map or Sets -


i have strange problem in have data in 3 columns of students follows,

student    initdate      findate     abc   2/2/2016     5/5/2017     abc   3/2/2016     3/30/2017     ced   1/1/2015     3/12/2017     lef   1/12/2016    11/17/2017     ced   1/12/1999    12/23/207     lef   2/13/2000    11/19/2017

my goal find lowest initdate of every student , highest findate of same student. data stored string have parse dates have done using dateformat parse date first.

initially, tried storing data in pair student,initdate , other pair student,findate, , tried storing data in hashmap date key problem store unique data , if 2 students have same initial dates 1 of them stored in hashmap.

i realized cannot use set , maps store data store unique values have decided use list.

i have created 3 lists, 1 of type string , other 2 of type date, can store duplicate data. have stored student names in 1 list , dates in other 2 lists.

what want sort list of students in such way initdate , findate sorted according student.

is there anyway sort 1 list based on other list in case of hashmaps ?

have considered writing own student class properties need , storing them list of student objects? can iterate through list of student objects find lowest value of init date , iterate through once more find highest fin date student id equal student id of first student object you've found.


-

Popular posts from this blog

node.js - How do I prevent MongoDB replica set from querying the primary? -

read-operations-only: is there way have mongodb replica set, make mongodb instance on box connected to, mongodb gets queried? i have 3 ec2 instances behind aws load balancer. on each ec2 instance runs mongodb, part of replica set. i have express endpoints on nodejs , connect replica set follows mongodb.mongoclient.connect('mongodb://1.1.1.1,2.2.2.2,3.3.3.3.', function (err, db) { if (err) { complete('{}'); } else { i distribute load of queries evenly across 3 instances of mongodb replica set instead of default having queries routed ec2 instance primary mongodb defined, because destroys point of load balancer (which balance load of queries across 3 instances evenly). my understanding when connecting mongodb replica set, primary instance selected unless primary instance down, , therefore purpose of every secondary instance serve backup. in example people call hot,cold,cold. because there 2...
Read more

Apache NiFi ExecuteScript: Groovy script to replace Json values via a mapping file -

i working apache nifi 0.5.1 on groovy script replace incoming json values ones contained in mapping file. mapping file looks (it simple .txt): header1;header2;header3 a;some text;a2 i have started following: import groovy.json.jsonbuilder import groovy.json.jsonslurper import java.nio.charset.standardcharsets def flowfile = session.get(); if (flowfile == null) { return; } flowfile = session.write(flowfile, { inputstream, outputstream -> def content = """ { "field1": "a" "field2": "a", "field3": "a" }""" def slurped = new jsonslurper().parsetext(content) def builder = new jsonbuilder(slurped) builder.content.field1 = "a" builder.content.field2 = "some text" builder.content.field3 = "a2" outputstream.write(builder.toprettystring().ge...
Read more