org.apache.commons.compress.archivers.sevenz

## Class SevenZFile

- java.lang.Object
- - org.apache.commons.compress.archivers.sevenz.SevenZFile

- All Implemented Interfaces:
    Closeable, AutoCloseable

      public class SevenZFile
      extends Object
      implements Closeable

  Reads a 7z file, using SeekableByteChannel under the covers.

  The 7z file format is a flexible container that can contain many compression and encryption types, but at the moment only only Copy, LZMA, LZMA2, BZIP2, Deflate and AES-256 + SHA-256 are supported.

  The format is very Windows/Intel specific, so it uses little-endian byte order, doesn't store user/group or permission bits, and represents times using NTFS timestamps (100 nanosecond units since 1 January 1601). Hence the official tools recommend against using it for backup purposes on *nix, and recommend .tar.7z or .tar.lzma or .tar.xz instead.

  Both the header and file contents may be compressed and/or encrypted. With both encrypted, neither file names nor file contents can be read, but the use of encryption isn't plausibly deniable.

  Multi volume archives can be read by concatenating the parts in correct order - either manually or by using {link org.apache.commons.compress.utils.MultiReadOnlySeekableByteChannel} for example.

  Since:
    1.6
  This class is not thread-safe

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `SevenZFile(File fileName)` Reads a file as unencrypted 7z archive
    `SevenZFile(File fileName, byte[] password)` Deprecated. use the char[]-arg version for the password instead
    `SevenZFile(File fileName, char[] password)` Reads a file as 7z archive
    `SevenZFile(File fileName, char[] password, SevenZFileOptions options)` Reads a file as 7z archive with additional options.
    `SevenZFile(File fileName, SevenZFileOptions options)` Reads a file as unencrypted 7z archive
    `SevenZFile(SeekableByteChannel channel)` Reads a SeekableByteChannel as 7z archive `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.
    `SevenZFile(SeekableByteChannel channel, byte[] password)` Deprecated. use the char[]-arg version for the password instead
    `SevenZFile(SeekableByteChannel channel, char[] password)` Reads a SeekableByteChannel as 7z archive `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.
    `SevenZFile(SeekableByteChannel channel, char[] password, SevenZFileOptions options)` Reads a SeekableByteChannel as 7z archive with additional options.
    `SevenZFile(SeekableByteChannel channel, SevenZFileOptions options)` Reads a SeekableByteChannel as 7z archive with addtional options.
    `SevenZFile(SeekableByteChannel channel, String fileName)` Reads a SeekableByteChannel as 7z archive `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.
    `SevenZFile(SeekableByteChannel channel, String fileName, byte[] password)` Deprecated. use the char[]-arg version for the password instead
    `SevenZFile(SeekableByteChannel channel, String fileName, char[] password)` Reads a SeekableByteChannel as 7z archive `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.
    `SevenZFile(SeekableByteChannel channel, String fileName, char[] password, SevenZFileOptions options)` Reads a SeekableByteChannel as 7z archive with addtional options.
    `SevenZFile(SeekableByteChannel channel, String fileName, SevenZFileOptions options)` Reads a SeekableByteChannel as 7z archive with additional options.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `close()` Closes the archive.
    `String` | `getDefaultName()` Derives a default file name from the archive name - if known.
    `Iterable<SevenZArchiveEntry>` | `getEntries()` Returns a copy of meta-data of all archive entries.
    `InputStream` | `getInputStream(SevenZArchiveEntry entry)` Returns an InputStream for reading the contents of the given entry.
    `SevenZArchiveEntry` | `getNextEntry()` Returns the next Archive Entry in this archive.
    `InputStreamStatistics` | `getStatisticsForCurrentEntry()` Provides statistics for bytes read from the current entry.
    `static boolean` | `matches(byte[] signature, int length)` Checks if the signature matches what is expected for a 7z file.
    `int` | `read()` Reads a byte of data.
    `int` | `read(byte[] b)` Reads data into an array of bytes.
    `int` | `read(byte[] b, int off, int len)` Reads data into an array of bytes.
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### SevenZFile

          public SevenZFile(File fileName,
                            char[] password)
                     throws IOException

      Reads a file as 7z archive
      Parameters:
        `fileName` - the file to read
        `password` - optional password if the archive is encrypted
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.17

    - #### SevenZFile

          public SevenZFile(File fileName,
                            char[] password,
                            SevenZFileOptions options)
                     throws IOException

      Reads a file as 7z archive with additional options.
      Parameters:
        `fileName` - the file to read
        `password` - optional password if the archive is encrypted
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

    - #### SevenZFile

          @Deprecated
          public SevenZFile(File fileName,
                                        byte[] password)
                                 throws IOException

      Deprecated. use the char[]-arg version for the password instead
      Reads a file as 7z archive
      Parameters:
        `fileName` - the file to read
        `password` - optional password if the archive is encrypted - the byte array is supposed to be the UTF16-LE encoded representation of the password.
      Throws:
        `IOException` - if reading the archive fails

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.13

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            SevenZFileOptions options)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive with addtional options.

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            char[] password)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `password` - optional password if the archive is encrypted
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.17

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            char[] password,
                            SevenZFileOptions options)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive with additional options.

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `password` - optional password if the archive is encrypted
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            String fileName,
                            char[] password)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `fileName` - name of the archive - only used for error reporting
        `password` - optional password if the archive is encrypted
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.17

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            String fileName,
                            char[] password,
                            SevenZFileOptions options)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive with addtional options.

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `fileName` - name of the archive - only used for error reporting
        `password` - optional password if the archive is encrypted
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            String fileName)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `fileName` - name of the archive - only used for error reporting
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.17

    - #### SevenZFile

          public SevenZFile(SeekableByteChannel channel,
                            String fileName,
                            SevenZFileOptions options)
                     throws IOException

      Reads a SeekableByteChannel as 7z archive with additional options.

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `fileName` - name of the archive - only used for error reporting
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

    - #### SevenZFile

          @Deprecated
          public SevenZFile(SeekableByteChannel channel,
                                        byte[] password)
                                 throws IOException

      Deprecated. use the char[]-arg version for the password instead
      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `password` - optional password if the archive is encrypted - the byte array is supposed to be the UTF16-LE encoded representation of the password.
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.13

    - #### SevenZFile

          @Deprecated
          public SevenZFile(SeekableByteChannel channel,
                                        String fileName,
                                        byte[] password)
                                 throws IOException

      Deprecated. use the char[]-arg version for the password instead
      Reads a SeekableByteChannel as 7z archive

      `SeekableInMemoryByteChannel` allows you to read from an in-memory archive.

      Parameters:
        `channel` - the channel to read
        `fileName` - name of the archive - only used for error reporting
        `password` - optional password if the archive is encrypted - the byte array is supposed to be the UTF16-LE encoded representation of the password.
      Throws:
        `IOException` - if reading the archive fails
      Since:
        1.13

    - #### SevenZFile

          public SevenZFile(File fileName)
                     throws IOException

      Reads a file as unencrypted 7z archive
      Parameters:
        `fileName` - the file to read
      Throws:
        `IOException` - if reading the archive fails

    - #### SevenZFile

          public SevenZFile(File fileName,
                            SevenZFileOptions options)
                     throws IOException

      Reads a file as unencrypted 7z archive
      Parameters:
        `fileName` - the file to read
        `options` - the options to apply
      Throws:
        `IOException` - if reading the archive fails or the memory limit (if set) is too small
      Since:
        1.19

  - ### Method Detail

    - #### close

          public void close()
                     throws IOException

      Closes the archive.
      Specified by:
        `close` in interface `Closeable`
      Specified by:
        `close` in interface `AutoCloseable`
      Throws:
        `IOException` - if closing the file fails

    - #### getNextEntry

          public SevenZArchiveEntry getNextEntry()
                                          throws IOException

      Returns the next Archive Entry in this archive.
      Returns:
        the next entry, or `null` if there are no more entries
      Throws:
        `IOException` - if the next entry could not be read

    - #### getEntries

          public Iterable<SevenZArchiveEntry> getEntries()

      Returns a copy of meta-data of all archive entries.

      This method only provides meta-data, the entries can not be used to read the contents, you still need to process all entries in order using `getNextEntry()` for that.

      The content methods are only available for entries that have already been reached via `getNextEntry()`.

      Returns:
        a copy of meta-data of all archive entries.
      Since:
        1.11

    - #### read

          public int read()
                   throws IOException

      Reads a byte of data.
      Returns:
        the byte read, or -1 if end of input is reached
      Throws:
        `IOException` - if an I/O error has occurred

    - #### getInputStream

          public InputStream getInputStream(SevenZArchiveEntry entry)
                                     throws IOException

      Returns an InputStream for reading the contents of the given entry.

      For archives using solid compression randomly accessing entries will be significantly slower than reading the archive sequentially.

      Parameters:
        `entry` - the entry to get the stream for.
      Returns:
        a stream to read the entry from.
      Throws:
        `IOException` - if unable to create an input stream from the zipentry
      Since:
        Compress 1.20

    - #### read

          public int read(byte[] b)
                   throws IOException

      Reads data into an array of bytes.
      Parameters:
        `b` - the array to write data to
      Returns:
        the number of bytes read, or -1 if end of input is reached
      Throws:
        `IOException` - if an I/O error has occurred

    - #### read

          public int read(byte[] b,
                          int off,
                          int len)
                   throws IOException

      Reads data into an array of bytes.
      Parameters:
        `b` - the array to write data to
        `off` - offset into the buffer to start filling at
        `len` - of bytes to read
      Returns:
        the number of bytes read, or -1 if end of input is reached
      Throws:
        `IOException` - if an I/O error has occurred

    - #### getStatisticsForCurrentEntry

          public InputStreamStatistics getStatisticsForCurrentEntry()

      Provides statistics for bytes read from the current entry.
      Returns:
        statistics for bytes read from the current entry
      Since:
        1.17

    - #### matches

          public static boolean matches(byte[] signature,
                                        int length)

      Checks if the signature matches what is expected for a 7z file.
      Parameters:
        `signature` - the bytes to check
        `length` - the number of bytes to check
      Returns:
        true, if this is the signature of a 7z archive.
      Since:
        1.8

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

    - #### getDefaultName

          public String getDefaultName()

      Derives a default file name from the archive name - if known.

      This implements the same heuristics the 7z tools use. In 7z's case if an archive contains entries without a name - i.e. `SevenZArchiveEntry.getName()` returns `null` - then its command line and GUI tools will use this default name when extracting the entries.

      Returns:
        null if the name of the archive is unknown. Otherwise if the name of the archive has got any extension, it is stripped and the remainder returned. Finally if the name of the archive hasn't got any extension then a `~` character is appended to the archive name.
      Since:
        1.19

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