Be sure that the lines list has the REMOVED label with the required lines in the correct places.

Question about the task

Tracking changes

Java Core, Level 9, Lesson 11

Resolved

Guys, Can you help me out here? I can't understand how to fix my code exactly...

Read 2 file names from the console: file1 and file2.
Both files contain text, but file2 is an updated version of file1. Some of the lines are still the same.
You need to create a merged version of the lines by writing them to the lines list.
The ADDED and REMOVED labels can't be used consecutively—they must always separated by the SAME label.
The example includes empty lines for clarity.
Neither the original file nor the updated file have empty lines!

Example 1:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 REMOVED line4 line5 line5 SAME line5 line0 ADDED line0 line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 ADDED line4 line5 line5 SAME line5 line0 REMOVED line0

Example 2:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line0 ADDED line0

In the example, empty lines mean that the line is not in the specified file.

Requirements:

The Solution class must contain a LineItem class.
The Solution class must have an enum called Type.
The Solution class must have a public static List<LineItem> field called lines that is initialized immediately.
In the main(String[] args) method, the program must read file names from the console (use BufferedReader).
In the main(String[] args) method, the BufferedReader used for reading input from the console must be closed after use.
The program must read the contents of the first and second file (use FileReader).
The file input streams (FileReader) must be closed.
The lines list should contain the merged version of the lines from the files. Each line should start with the label ADDED, REMOVED, or SAME, depending on the action taken.

package com.codegym.task.task19.task1916; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.List; /* Tracking changes */ public class Solution { public static List<LineItem> lines = new ArrayList<>(); public static void main(String[] args) throws IOException { try(BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) { String file1 = reader.readLine(); String file2 = reader.readLine(); FileReader fileReader1 = new FileReader(file1); FileReader fileReader2 = new FileReader(file2); fileReader1.close(); fileReader2.close(); trackingChanges(fileReader1, fileReader2); } catch (IOException e){} } public static void trackingChanges(FileReader reader1, FileReader reader2) throws IOException { BufferedReader readOrg = new BufferedReader(reader1); BufferedReader readUpd = new BufferedReader(reader2); List<String> org = new ArrayList<>(); List<String> upd = new ArrayList<>(); while (readOrg.ready() && readUpd.ready()){ org.add(readOrg.readLine()); upd.add(readUpd.readLine()); } readOrg.close(); readUpd.close(); int count1 = 0; int count2 = 0; while ((count1 != org.size()) && (count2 != upd.size())){ if (org.get(count1).equals(upd.get(count2))){ lines.add(new LineItem(Type.SAME, org.get(count1))); count1++; count2++; } else if (upd.get(count2).equals(org.get(count1 + 1))){ lines.add(new LineItem(Type.REMOVED, org.get(count1))); count1++; } else { lines.add(new LineItem(Type.ADDED, upd.get(count2))); count2++; } } } public static enum Type { ADDED, // New line added REMOVED, // Line deleted SAME // No change } public static class LineItem { public Type type; public String line; public LineItem(Type type, String line) { this.type = type; this.line = line; } } }

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Ahmad

Level 23 , Riyadh, Saudi Arabia

31 May 2020, 01:38

can anyone send me the solution stuck in this task for 3 days :|

Guadalupe Gagnon

Level 37 , Tampa, United States

1 April 2020, 18:31

the first problem is lines 26 and 27, closing the file readers before using them is throwing an error when they are used. Because the code is wrapped in a try catch block the error is just ignore and the program closes. Lines 42-44 probably won't read all the data from both files successfully, guaranteed not to when the files are of different lengths. When those are fixed I am also getting an IndexOutOfBoundsException on line 59. This is because org.get(count1 + 1) will be out of bounds when count1 is equal to the last index. The last thing is that you need to make sure that, during the figuring out if lines are ADDED, REMOVED, or SAME; that ADDED and/or REMOVED do not occur sequentially in the resulting lines list. If ADDED or REMOVED is used then the next lines must be SAME. The above code, when ADDED was reached, count1 never caught up with count2 and ADDED ended up being the last 3 entries with the test files I used.

Guadalupe Gagnon

Level 37 , Tampa, United States

1 April 2020, 18:34

Test Data File1: The tiger is in the loft. He looks over to the tiger in the tree. both tigers greet eachother. tiger 1 roars loudly. Other than that everything is fine. File2 (the updated): The tiger is in the loft. Tenaciously cleans himself. He looks over to the tiger in the tree. tiger 1 roars loudly. Ouch the other tiger says. Other than that everything is fine. The data stored in lines after running your algorithm: [LineItem{SAME - The tiger is in the loft.}, LineItem{ADDED - Tenaciously cleans himself.}, LineItem{SAME - He looks over to the tiger in the tree.}, LineItem{ADDED - tiger 1 roars loudly.}, LineItem{ADDED - Ouch the other tiger says.}, LineItem{ADDED - Other than that everything is fine.}] Correct data that should be in lines: [LineItem{SAME - The tiger is in the loft.}, LineItem{ADDED - Tenaciously cleans himself.}, LineItem{SAME - He looks over to the tiger in the tree.}, LineItem{REMOVED - both tigers greet eachother.}, LineItem{SAME - tiger 1 roars loudly.}, LineItem{ADDED - Ouch the other tiger says.}, LineItem{SAME - Other than that everything is fine.}]

Ivan

Level 22 , Nope, Bulgaria

8 April 2020, 10:03

Thank you, Guadalupe. Unfortunately, I had to copy/paste this one as I couldn't get my head around it ... ashamed from this task...

Facundo Villarroel

Level 20 , Berlin, Germany

5 May 2020, 18:19

Could you PM me the solution? I cannot make it pass, it's driving me crazy

yehuda b

Level 23 , Beersheba, Israel

10 September 2020, 20:31

@Guadalupe, I didn't even try to get the task done b4 looking in the discussion and then the help sections, I have no idea how a person could figure out what exactly this (hard) [not explained] task is requiring you to do, and then me in particular, either because I'm stupid or just exhausted today, it took me half an hour to get to this comment just to finally get what I'm supposed to do, I didn't even yet start to implement the logic besides for creating BufferedReader but if a coding job would mean figuring out my boss's shenanigans by reading his\her mind or something, then I'm out.

yehuda b

Level 23 , Beersheba, Israel

10 September 2020, 20:35

@Ivan, I don't think there is anything to be ashamed of, it is almost impossible for any homo-sapiens to wrap his head around something just simply unexplained.

yehuda b

Level 23 , Beersheba, Israel

10 September 2020, 20:48

And I guess to make it "easier" (even more confusing) they don't have added and removed consecutively, but what if the scriptwriter wants to change a given line to something else (not just remove it)??