Help please!

Question about the task

Archiver (part 13)

Java Multithreading, Level 7, Lesson 15

Under discussion

Where am I going wrong?

public List<FileProperties> getFileList() throws Exception {
    if (!Files.isRegularFile(zipFile)) throw new NoSuchZipFileException();

    List<FileProperties> files = new ArrayList<>();

    try (ZipInputStream zipInputStream = new ZipInputStream(Files.newInputStream(zipFile))) {
        ZipEntry zipEntry;

        while ((zipEntry = zipInputStream.getNextEntry()) != null) {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            copyData(zipInputStream, baos);

            files.add(new FileProperties(zipEntry.getName(), zipEntry.getSize(),
                    zipEntry.getCompressedSize(), zipEntry.getMethod()));
        }
    }

    return files;
}

Let's continue to move toward getting the contents of an archive. Let's write a getFileList() method inside the ZipFileManager class. It will return a list of the files in the archive, or rather a list of the properties of these files (we already implemented the FileProperties class).
Let's begin:
1. Add a List<FileProperties> getFileList() throws Exception method to the ZipFileManager class.
2. Inside that method, check whether zipFile is a regular file using a suitable method from the Files class. If it is not a file, throw a NoSuchZipFileException.
3. Create a list of FileProperties objects. We'll add the file properties to it.
4. Create a ZipInputStream for the file represented by the zipFile variable. As we've done before, wrap the creation of this object in a try-with-resources.
5. Go through all of the ZipEntries in the ZipInputStream
6. For each ZipEntry, read its contents (otherwise, we won't have information about its size). You can't find the size of a file in an archive without reading it. This is super easy to do using the copyData method and a temporary ByteArrayOutputStream buffer.
7. Get the name, size, compressed size, and compression method of the zip entry. Take a look at what else you can learn about the entry.
8. Create a FileProperties object using the obtained file data.
9. Add the object created in step 8 to the list from step 3.
10. Return the gathered information to the method that called the getFileList method.

Requirements:

You need to create a public List<FileProperties> getFileList() throws Exception method in the ZipFileManager class.
If Path zipFile is not a file, then the getFileList method should throw a NoSuchZipFileException.
The getFileList method should go through all of the archive's files and return data about them. The method must be implemented according to the task conditions.
The stream used to read from the archive must be closed.

package com.codegym.task.task31.task3110; import com.codegym.task.task31.task3110.exception.NoSuchZipFileException; import java.io.IOException; public class Archiver { public static void main(String[] args) throws IOException { Operation operation = null; do { try { operation = askOperation(); CommandExecutor.execute(operation); } catch (NoSuchZipFileException e) { ConsoleHelper.writeMessage("You didn't select an archive or you selected an invalid file."); } catch (Exception ex) { ConsoleHelper.writeMessage("An error occurred. Please check the entered data."); } } while (operation != Operation.EXIT); } public static Operation askOperation() throws IOException { ConsoleHelper.writeMessage("Select an operation:\n" + "0 - Zip files into an archive\n" + "1 - Add a file to an archive\n" + "2 - Remove a file from an archive\n" + "3 - Extract an archive\n" + "4 - View the contents of an archive\n" + "5 - Exit"); return Operation.values()[ConsoleHelper.readInt()]; } }

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KIN SOCHEAT

Level 34 , Phnom Penh, Cambogia

13 July 2020, 09:43

i pass by close only new ByteArrayOutputStream

Nicholas Grube

Level 41 , Carrollton, TX, United States

23 March 2020, 19:34

Don't forget to close the ZipEntry after reading it in (Look for the right method in ZipFileInputStream) and close the ByteArrayOutputStream as well.

Iliri Cani

Level 37 , Tirana, Albania

27 August 2019, 08:56

You should close the entry at the end of while loop.