Package com.helger.commons.io.file

Class FileHelper

java.lang.Object
com.helger.commons.io.file.FileHelper
@Immutable public final class FileHelper extends Object
Miscellaneous file utility methods.
Author:
Philip Helger

  • Method Details

    • existsFile

      public static boolean existsFile(@Nullable File aFile)
      Check if the passed file exists. Must be existing and a file.
      Parameters:
      aFile - The file to be checked for existence. May be null .
      Returns:
      true if the passed file is non-null, is a file and exists, false otherwise.

    • existsDir

      public static boolean existsDir(@Nullable File aDir)
      Check if the passed directory exists. Must be existing and must be a directory!
      Parameters:
      aDir - The directory to be checked for existence. May be null.
      Returns:
      true if the passed directory is not null, is a directory and exists, false otherwise.

    • canReadAndWriteFile

      public static boolean canReadAndWriteFile(@Nullable File aFile)
      Check if the passed file can read and write. If the file already exists, the file itself is checked. If the file does not exist, the parent directory
      Parameters:
      aFile - The file to be checked. May be null.
      Returns:
      true if the file can be read and written

    • ensureParentDirectoryIsPresent

      @Nonnull public static EChange ensureParentDirectoryIsPresent(@Nonnull File aFile)

    • getCanonicalFile

      @Nullable public static File getCanonicalFile(@Nullable File aFile) throws IOException
      Get the canonical file of the passed file, if the file is not null.
      Parameters:
      aFile - The file to get the canonical path from. May be null.
      Returns:
      null if the passed file is null.
      Throws:
      IOException - If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries

    • getCanonicalFileOrNull

      @Nullable public static File getCanonicalFileOrNull(@Nullable File aFile)
      Get the canonical file of the passed file, if the file is not null. In case of an IOException, null is returned.
      Parameters:
      aFile - The file to get the canonical path from. May be null.
      Returns:
      null if the passed file is null or an exception occurred.

    • getCanonicalPath

      @Nullable public static String getCanonicalPath(@Nullable File aFile) throws IOException
      Get the canonical path of the passed file, if the file is not null.
      Parameters:
      aFile - The file to get the canonical path from. May be null.
      Returns:
      null if the passed file is null.
      Throws:
      IOException - If an I/O error occurs, which is possible because the construction of the canonical pathname may require filesystem queries

    • getCanonicalPathOrNull

      @Nullable public static String getCanonicalPathOrNull(@Nullable File aFile)
      Get the canonical path of the passed file, if the file is not null. In case of an IOException, null is returned.
      Parameters:
      aFile - The file to get the canonical path from. May be null.
      Returns:
      null if the passed file is null.

    • isParentDirectory

      public static boolean isParentDirectory(@Nonnull File aSearchDirectory, @Nonnull File aStartDirectory)
      Check if the searched directory is a parent object of the start directory
      Parameters:
      aSearchDirectory - The directory to be searched. May not be null.
      aStartDirectory - The directory where the search starts. May not be null.
      Returns:
      true if the search directory is a parent of the start directory, false otherwise.
      See Also:

    • getInputStream

      @Nullable public static FileInputStream getInputStream(@Nonnull File aFile)

    • getBufferedInputStream

      @Nullable public static NonBlockingBufferedInputStream getBufferedInputStream(@Nonnull File aFile)

    • getReader

      @Nullable public static InputStreamReader getReader(@Nonnull File aFile, @Nonnull Charset aCharset)

    • getBufferedReader

      @Nullable public static NonBlockingBufferedReader getBufferedReader(@Nonnull File aFile, @Nonnull Charset aCharset)

    • getOutputStream

      @Nullable public static FileOutputStream getOutputStream(@Nonnull File aFile)
      Get an output stream for writing to a file.
      Parameters:
      aFile - The file to write to. May not be null.
      Returns:
      null if the file could not be opened

    • getOutputStream

      @Nullable public static FileOutputStream getOutputStream(@Nonnull File aFile, @Nonnull EAppend eAppend)
      Get an output stream for writing to a file.
      Parameters:
      aFile - The file to write to. May not be null.
      eAppend - Appending mode. May not be null.
      Returns:
      null if the file could not be opened

    • getBufferedOutputStream

      @Nullable public static NonBlockingBufferedOutputStream getBufferedOutputStream(@Nonnull File aFile)

    • getBufferedOutputStream

      @Nullable public static NonBlockingBufferedOutputStream getBufferedOutputStream(@Nonnull File aFile, @Nonnull EAppend eAppend)

    • getWriter

      @Nullable public static OutputStreamWriter getWriter(@Nonnull File aFile, @Nonnull Charset aCharset)

    • getWriter

      @Nullable public static OutputStreamWriter getWriter(@Nonnull File aFile, @Nonnull EAppend eAppend, @Nonnull Charset aCharset)

    • getBufferedWriter

      @Nullable public static NonBlockingBufferedWriter getBufferedWriter(@Nonnull File aFile, @Nonnull Charset aCharset)

    • getBufferedWriter

      @Nullable public static NonBlockingBufferedWriter getBufferedWriter(@Nonnull File aFile, @Nonnull EAppend eAppend, @Nonnull Charset aCharset)

    • getPrintWriter

      @Nullable public static PrintWriter getPrintWriter(@Nonnull File aFile, @Nonnull Charset aCharset)

    • getPrintWriter

      @Nullable public static PrintWriter getPrintWriter(@Nonnull File aFile, @Nonnull EAppend eAppend, @Nonnull Charset aCharset)

    • getRandomAccessFile

      @Nullable public static RandomAccessFile getRandomAccessFile(@Nonnull String sFilename, @Nonnull ERandomAccessFileMode eMode)

    • getRandomAccessFile

      @Nullable public static RandomAccessFile getRandomAccessFile(@Nonnull File aFile, @Nonnull ERandomAccessFileMode eMode)

    • isFileNewer

      public static boolean isFileNewer(@Nonnull File aFile1, @Nonnull File aFile2)
      Returns true if the first file is newer than the second file. Returns true if the first file exists and the second file does not exist. Returns false if the first file is older than the second file. Returns false if the first file does not exists but the second does. Returns false if none of the files exist.
      Parameters:
      aFile1 - First file. May not be null.
      aFile2 - Second file. May not be null.
      Returns:
      true if the first file is newer than the second file, false otherwise.

    • getFileSizeDisplay

      @Nonnull public static String getFileSizeDisplay(@Nullable File aFile)

    • getFileSizeDisplay

      @Nonnull public static String getFileSizeDisplay(@Nullable File aFile, @Nonnegative int nDecimals)

    • getFileSizeDisplay

      @Nonnull public static String getFileSizeDisplay(long nFileSize)

    • getFileSizeDisplay

      @Nonnull public static String getFileSizeDisplay(@Nonnegative long nFileSize, @Nonnegative int nDecimals)

    • getSecureFile

      @Nullable public static File getSecureFile(@Nullable File aFile)
      Get a secure File object based on the passed file object. First all relative paths ("." and "..") are resolved and all eventually contained '\0' characters are eliminated. Than all file names are checked for validity (so that no special characters are contained).
      Parameters:
      aFile - The file to be secured.
      Returns:
      null if the passed file is null.

    • getDirectoryObjectCount

      @Nonnegative public static int getDirectoryObjectCount(@Nonnull File aDirectory)
      Returns the number of files and directories contained in the passed directory excluding the system internal directories.
      Parameters:
      aDirectory - The directory to check. May not be null and must be a directory.
      Returns:
      A non-negative number of objects in that directory.
      See Also:

    • getDirectoryContent

      @Nonnull @ReturnsMutableCopy public static ICommonsList<File> getDirectoryContent(@Nonnull File aDirectory)
      This is a replacement for File.listFiles() doing some additional checks on permissions. The order of the returned files is defined by the underlying File.listFiles() method.
      Parameters:
      aDirectory - The directory to be listed. May not be null.
      Returns:
      Never null.

    • getDirectoryContent

      @Nonnull @ReturnsMutableCopy public static ICommonsList<File> getDirectoryContent(@Nonnull File aDirectory, @Nonnull FilenameFilter aFilenameFilter)
      This is a replacement for File.listFiles(FilenameFilter) doing some additional checks on permissions. The order of the returned files is defined by the underlying File.listFiles(FilenameFilter) method.
      Parameters:
      aDirectory - The directory to be listed. May not be null.
      aFilenameFilter - The filename filter to be used. May not be null.
      Returns:
      Never null.

    • getDirectoryContent

      @Nonnull @ReturnsMutableCopy public static ICommonsList<File> getDirectoryContent(@Nonnull File aDirectory, @Nonnull FileFilter aFileFilter)
      This is a replacement for File.listFiles(FileFilter) doing some additional checks on permissions. The order of the returned files is defined by the underlying File.listFiles(FileFilter) method.
      Parameters:
      aDirectory - The directory to be listed. May not be null.
      aFileFilter - The file filter to be used. May not be null.
      Returns:
      Never null.

    • getAsURL

      @Nullable public static URL getAsURL(@Nonnull File aFile)

    • getAsURLString

      @Nullable public static String getAsURLString(@Nonnull File aFile)