Can someone take a look for me please?

Question about the task

CRUD 2

Java Core, Level 7, Lesson 10

Resolved

Cannot verify 3-6, i think i did it right tho?

Batch CrUD: multiple Creations, Updates, Deletions.

The program runs with one of the following sets of arguments:
-c name1 sex1 bd1 name2 sex2 bd2 ... -u id1 name1 sex1 bd1 id2 name2 sex2 bd2 ... -d id1 id2 id3 id4 ... -i id1 id2 id3 id4 ...

Argument values:
name (String)
sex ("m" or "f")
bd (birth date in the following format: 04 15 1990)
-c (adds all people with the specified arguments to the end of allPeople; displays their ids in the appropriate order)
-u (updates the corresponding data of people with the specified ids)
-d (performs the logical deletion of the person with the specified id; replaces all of its data with null)
-i (displays information about all people with the specified ids: name sex bd)

The id corresponds to the index in the list.
The birth date format is Apr 15 1990.
All the people should be stored in allPeople.
The order in which data is displayed corresponds to the order in which is input.
Be sure the program is thread safe (works correctly with multiple threads without corrupting the data).
Use Locale.ENGLISH as the second argument for SimpleDateFormat.

Example output for the -i argument with two ids:
Washington m Apr 15 1990 Ross f Apr 25 1997

Requirements:

The Solution class must contain a public volatile List<Person> field called allPeople.
The Solution class must have a static block where two people are added to the allPeople list.
With the -c argument, the program must add all people with the specified arguments to the end of the allPeople list, and display the id of each of them.
With the -u argument, the program must update the data of the people with the specified ids in the allPeople list.
With the -d argument, the program must perform the logical deletion of the people with the specified ids in the allPeople list.
With the -i argument, the program should display data about all the people with the specified ids according to the format specified in the task.
The Solution class's main method must contain a switch statement based on args[0].
Each case label in the switch statement must have a synchronization block for allPeople.

package com.codegym.task.task17.task1711; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; import java.util.List; import java.util.Locale; /* CRUD 2 */ public class Solution { public static volatile List<Person> allPeople = new ArrayList<>(); static volatile int index = 1; static { allPeople.add(Person.createMale("Donald Chump", new Date())); // id=0 allPeople.add(Person.createMale("Larry Gates", new Date())); // id=1 } public static void main(String[] args) { // Start here try { String pattern1 = "MM dd yyyy"; SimpleDateFormat sf1 = new SimpleDateFormat(pattern1, Locale.US); String pattern2 = "MMM dd yyyy"; SimpleDateFormat sf2 = new SimpleDateFormat(pattern2, Locale.US); switch (args[0]){ case "-c": synchronized (allPeople){ while(index+3 <args.length+1) { if (args[index + 1].equals("m")) { Person newPerson = Person.createMale(args[index], sf1.parse(args[index+2])); allPeople.add(newPerson); System.out.println(allPeople.indexOf(newPerson)); index +=3; } else if (args[index+1].equals("f")) { Person newPerson = Person.createFemale(args[index], sf1.parse(args[index+2])); allPeople.add(newPerson); System.out.println(allPeople.indexOf(newPerson)); index +=3; } }} break; case "-u": synchronized(allPeople) { while (index + 3 < args.length + 1) { if (args[index+2].equals("m")) { allPeople.set(Integer.valueOf(args[index]), Person.createMale(args[index+1], sf1.parse(args[index+3]))); index += 3; } else if (args[index+2].equals("f")) { allPeople.set(Integer.valueOf(args[index]), Person.createFemale(args[index+1], sf1.parse(args[index+3]))); index += 3; } } } break; case "-d": synchronized (allPeople) { for (String s : args) { allPeople.get(Integer.valueOf(s)).setBirthDate(null); allPeople.get(Integer.valueOf(s)).setName(null); allPeople.get(Integer.valueOf(s)).setSex(null); } } break; case "-i": synchronized (allPeople) { for (String s : args) { Person p = allPeople.get(Integer.valueOf(s)); System.out.print(p.getName() + " " + (p.getSex() == (Sex.MALE) ? "m" : "f") + " " + sf2.format(p.getBirthDate())); } } break; } }catch(ParseException e){ e.printStackTrace(); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

21 September 2020, 15:06

useful

in the case blocks for "-i" and "-d", a null pointer exception will occur because a for each loop is going to start with args[0], which will be "-i" or "-d" and will not pull a valid object from the allPeople ArrayList. This will need to be addressed. In the "-c" and "-u" block, the while loop will allow access to indices past the length of allPeople. This is a result adding 1 to the length checked on lines 34 and 51. Also, it should be +4 in the "-u" block, not plus three because there is an id.

Davedabull

Level 22 , New York City, United States

21 September 2020, 15:07

thank you very much for the hints!!!

Davedabull

Level 22 , New York City, United States

21 September 2020, 15:04

I fixed my errors: the -d and -i block is just wrong, the first arguments would be -d and -i so the for each loop wouldnt work; for the -c and -u block, i got ride of the while loop and use a for loop; for the -i block, after each iteration, it should add 4 instead of 3