Hello, much appreciated if you could tell me what's wrong

Question about the task

Shortener (9)

Java Collections, Level 6, Lesson 15

Under discussion

Tried a few things but didn't work, so I put it here as I left it.

Let's write another strategy. We'll call it FileStorageStrategy. It will be very similar to OurHashMapStorageStrategy, but files will be the buckets. I'm sure you know what I mean by buckets. If not, copy the internal workings of HashMap.
9.1. Create a FileBucket class in the strategy package.
9.2. Add a Path path field to the class. This will be the path to the file.
9.3. Add a no-argument constructor to the class. It should:
9.3.1. Initialize the path field with a temporary file. The file must be placed in the directory for temporary files and have a random name.

Hint: Files.createTempFile.

9.3.2. Use the path field to create a new file. If the file already exists, then replace it.
9.3.3. Ensure the file is deleted when you exit the program.

Hint: deleteOnExit().

9.4. Add the following methods to the class:
9.4.1. long getFileSize() - Returns the size of the file pointed to by path.
9.4.2. void putEntry(Entry entry) - Serializes the passed entry to the file. Be aware that each entry may contain another entry.
9.4.3. Entry getEntry() - Gets an entry from the file. If the file size is zero, return null.
9.4.4. void remove() - Delete the file pointed to by path.
The constructor and methods should not throw exceptions.

Requirements:

A Path path field must be created in the FileBucket class.
The FileBucket class's no-argument constructor must be implemented in accordance with the task conditions.
The getFileSize method must return the size of the file pointed to by path.
The putEntry method must serialize the passed Entry object to the file pointed to by path. To get an OutputStream, use the Files.newOutputStream method.
The getEntry method must deserialize an Entry object from the file pointed to by path. To get an InputStream, use the Files.newInputStream method.
The remove method should delete the file pointed to by path using the Files.delete() method.

package com.codegym.task.task33.task3310; import com.codegym.task.task33.task3310.strategy.Entry; import com.codegym.task.task33.task3310.strategy.FileBucket; import com.codegym.task.task33.task3310.strategy.HashMapStorageStrategy; import com.codegym.task.task33.task3310.strategy.StorageStrategy; import java.io.IOException; import java.text.ParseException; import java.util.Date; import java.util.HashSet; import java.util.Set; import java.util.stream.Collectors; public class Solution { public static void main(String[] args) { testStrategy(new HashMapStorageStrategy(), 10000); } public static Set<Long> getIds(Shortener shortener, Set<String> strings) { return strings.stream().map(shortener::getId).collect(Collectors.toSet()); } public static Set<String> getStrings(Shortener shortener, Set<Long> keys) { return keys.stream().map(shortener::getString).collect(Collectors.toSet()); } public static void testStrategy(StorageStrategy strategy, long elementsNumber) { Set<String> elements = new HashSet<>(); System.out.println(strategy.getClass().getName().substring(strategy.getClass().getName().lastIndexOf(".") + 1)); for(int i = 0; i < elementsNumber; i++){ elements.add(Helper.generateRandomString()); } Shortener shortener = new Shortener(strategy); long idStart = new Date().getTime(); Set<Long> ids = getIds(shortener, elements); long idEnd = new Date().getTime(); System.out.println(idEnd - idStart); long strStart = new Date().getTime(); Set<String> strings = getStrings(shortener, ids); long strEnd = new Date().getTime(); System.out.println(strEnd - strStart); if(elements.containsAll(strings)) System.out.println("The test passed."); else System.out.println("The test failed."); } public static long difference(String start, String end) { String[] split = start.split(":"); String[] split2 = end.split(":"); int timeOne = 0; int timeTwo = 0; for(String a : split){ timeOne += Integer.parseInt(a); } for(String a : split2){ timeTwo += Integer.parseInt(a); } return timeTwo - timeOne; } }

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Seth

Level 38 , Warsaw, Poland

20 May 2020, 13:10

useful

It took me 16 attempts but i finally solved this stupid task. The validator wanted me to use both .createFile and .createTempFile so i did this:

public FileBucket() {
    try {
        path = Files.createTempFile(Helper.generateRandomString(), ".txt");
        Files.deleteIfExists(path);
        Files.createFile(path);
        path.toFile().deleteOnExit();
    } catch (IOException e) {
    }
}

Kamil

Level 31 , Near Warsaw, Poland

22 May 2020, 15:57

How'd get it to work with initialization of path variable? I thought Files.createTempFile returns File Object? I must be doing something wrong then

AnnemiekFF

Level 41 , Breda, Netherlands

15 May 2020, 07:30

useful

1) You should not put the type to null, but make it "txt" in your createTempFile(). 2) in Files, you have the method deleteIfExists. That is the one you want to use. 3) also in Files, you have the createFile. You don't have to add that to any variable, just call the method. 4) Wrap 1 -3 in a try, catch method so you do not throw an exception from the constructor. 5) exit as you do after the try-catch.

Kamil

Level 31 , Near Warsaw, Poland

22 May 2020, 15:51

Thank you for response and advice as well, my constructor now looks like this. Although your suggestion that I made in my code, still don't wanna pass the requirements, saying that variable path must be initialized by Files.createTempFile. I can't initialize Path with File object so I use .toPath() method. Still nothing. These requirements give me a fuckbrain sometimes...

public FileBucket() {
        try{
            this.path = File.createTempFile(Helper.generateRandomString(), ".txt").toPath();
            Files.deleteIfExists(path);
            Files.createFile(path);
        } catch (Exception e) {

        }

        path.toFile().deleteOnExit();

    }