Package org.openjdk.jmc.common.io

Class IOToolkit

java.lang.Object
org.openjdk.jmc.common.io.IOToolkit
public final class IOToolkit extends Object
Common functionality you might want when you're working with I/O.

  • Method Details

    • closeSilently

      public static void closeSilently(Closeable closeable)
      Closes a closeable. Typically you call this in a final statement so the method also ignores if the closeable is null.
      Parameters:
      closeable - object to close, may be null

    • openUncompressedStream

      public static InputStream openUncompressedStream(File file) throws IOException
      Get an input stream for a optionally compressed file. If the file is compressed using GZip, ZIP or LZ4, then an appropriate unpacking will be done.
      Parameters:
      file - file to read from
      Returns:
      input stream for the unpacked file content
      Throws:
      IOException - on I/O error

    • openUncompressedStream

      public static InputStream openUncompressedStream(InputStream stream) throws IOException
      Get an input stream for a optionally compressed input stream. If the file is compressed using GZip, ZIP or LZ4, then an appropriate unpacking will be done.
      Parameters:
      stream - input stream to read from
      Returns:
      input stream for the unpacked content
      Throws:
      IOException - on I/O error

    • hasMagic

      public static boolean hasMagic(File file, int[] magic) throws IOException
      Checks if a file begins with a specified array of bytes.
      Parameters:
      file - the file to examine
      magic - the magic data, an array with values between 0 and 255
      Returns:
      true if the file begins with the magic, false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the file

    • hasMagic

      public static boolean hasMagic(InputStream is, int[] magic) throws IOException
      Checks if an input stream begins with a specified array of bytes. The input stream will be positioned at the first byte after the magic data after this call.
      Parameters:
      is - the input stream to examine
      magic - the magic data, an array with values between 0 and 255
      Returns:
      true if the input stream begins with the magic, false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the stream

    • isGZipFile

      public static boolean isGZipFile(File file) throws IOException
      Returns true if the file is GZip file.
      Parameters:
      file - the file to examine
      Returns:
      true if it is a GZip file, false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the file

    • isLZ4File

      public static boolean isLZ4File(File file) throws IOException
      Returns true if the file is LZ4 compressed.
      Parameters:
      file - the file to examine
      Returns:
      true if it is an LZ4 compressed file, false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the file

    • isZipFile

      public static boolean isZipFile(File file) throws IOException
      Checks if the file is a ZIP archive.
      Parameters:
      file - the file to examine
      Returns:
      true if it's a ZIP archive, false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the file

    • getGzipMagic

      public static int[] getGzipMagic()
      Returns the magic bytes for identifying Gzip. This is a defensive copy. It's up to the user to cache this to avoid excessive allocations.
      Returns:
      a copy of the magic bytes for Gzip.

    • getZipMagic

      public static int[] getZipMagic()
      Returns the magic bytes for identifying Zip. This is a defensive copy. It's up to the user to cache this to avoid excessive allocations.
      Returns:
      a copy of the magic bytes for Zip.

    • getLz4Magic

      public static int[] getLz4Magic()
      Returns the magic bytes for identifying LZ4. This is a defensive copy. It's up to the user to cache this to avoid excessive allocations.
      Returns:
      a copy of the magic bytes for LZ4.

    • isCompressedFile

      public static boolean isCompressedFile(File file) throws IOException
      Checks if the file is compressed in a way compatible with openUncompressedStream(File).
      Parameters:
      file - the file to examine
      Returns:
      true if the file is compressed in a manner which can be uncompressed by openUncompressedStream(File), false otherwise
      Throws:
      IOException - if an error occurred when trying to read from the file

    • loadFromFile

      public static List<String> loadFromFile(File file) throws IOException
      Read lines from a text file.
      Parameters:
      file - file to read lines from
      Returns:
      a list of strings, one for each line in the file
      Throws:
      IOException - on I/O error
      See Also:

    • saveToFile

      public static void saveToFile(File file, List<String> lines) throws IOException
      Write lines to a text file. If the file already exists, it will be overwritten.
      Parameters:
      file - file to write lines to
      lines - a list of strings that will be written on one line each
      Throws:
      IOException - on I/O error
      See Also:

    • loadFromStream

      public static List<String> loadFromStream(InputStream is) throws IOException
      Read lines from an input stream.
      Parameters:
      is - input stream to read lines from
      Returns:
      a list of strings, one for each line in the stream
      Throws:
      IOException - on I/O error
      See Also:

    • write

      public static void write(InputStream in, File toOutput, boolean append) throws IOException
      Copy all data from an input stream to a file.
      Parameters:
      in - input stream to read from
      toOutput - file to write to
      append - true if the file should be appended to, false if it should be overwritten
      Throws:
      IOException - on I/O error

    • copy

      public static void copy(InputStream is, OutputStream os) throws IOException
      Copy all data from an input stream to an output stream.
      Parameters:
      is - input stream to read from
      os - output stream to write to
      Throws:
      IOException - on I/O error

    • copy

      public static void copy(InputStream is, OutputStream os, int bufferSize) throws IOException
      Copy all data from an input stream to an output stream.
      Parameters:
      is - input stream to read from
      os - output stream to write to
      bufferSize - size of the buffer used when copying data
      Throws:
      IOException - on I/O error

    • copyFile

      public static void copyFile(File srcFile, File targetFile) throws IOException
      Copies srcFile to targetFile. Will do nothing if srcFile and targetFile are the same file. Will copy file attributes.
      Parameters:
      srcFile - source file to copy data from
      targetFile - target file to copy data to
      Throws:
      IOException - if something goes wrong during the copy

    • calculateFileHash

      public static String calculateFileHash(File file) throws IOException
      Calculates an MD5 hash on ten evenly distributed 1kB blocks from the file.
      Parameters:
      file - file to calculate hash for
      Returns:
      MD5 hash string
      Throws:
      IOException - if something goes wrong when reading file data