Class DirFile

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<java.io.File>, StorageFile

    class DirFile
    extends java.io.File
    implements StorageFile
    This class provides a disk based implementation of the StorageFile interface. It is used by the database engine to access persistent data and transaction logs under the directory (default) subsubprotocol.
    • Constructor Summary

      Constructors 
      Constructor Description
      DirFile​(java.lang.String path)
      Construct a DirFile from a path name.
      DirFile​(java.lang.String directoryName, java.lang.String fileName)
      Construct a DirFile from a directory name and a file name.
      DirFile​(DirFile directoryName, java.lang.String fileName)
      Construct a DirFile from a directory name and a file name.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean deleteAll()
      Deletes the named file and, if it is a directory, all the files and directories it contains.
      int getExclusiveFileLock()
      Get an exclusive lock.
      java.io.InputStream getInputStream()
      Creates an input stream from a file name.
      java.io.OutputStream getOutputStream()
      Creates an output stream from a file name.
      java.io.OutputStream getOutputStream​(boolean append)
      Creates an output stream from a file name.
      StorageFile getParentDir()
      Get the name of the parent directory if this name includes a parent.
      StorageRandomAccessFile getRandomAccessFile​(java.lang.String mode)
      Get a random access (read/write) file.
      void limitAccessToOwner()
      Use when creating a new file.
      void releaseExclusiveFileLock()
      Release the resource associated with an earlier acquired exclusive lock
      boolean renameTo​(StorageFile newName)
      Rename the file denoted by this name.
      • Methods inherited from class java.io.File

        canExecute, canRead, canWrite, compareTo, createNewFile, createTempFile, createTempFile, delete, deleteOnExit, equals, exists, getAbsoluteFile, getAbsolutePath, getCanonicalFile, getCanonicalPath, getFreeSpace, getName, getParent, getParentFile, getPath, getTotalSpace, getUsableSpace, hashCode, isAbsolute, isDirectory, isFile, isHidden, lastModified, length, list, list, listFiles, listFiles, listFiles, listRoots, mkdir, mkdirs, renameTo, setExecutable, setExecutable, setLastModified, setReadable, setReadable, setReadOnly, setWritable, setWritable, toPath, toString, toURI, toURL
      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait
    • Field Detail

      • lockFileOpen

        private java.io.RandomAccessFile lockFileOpen
      • lockFileChannel

        private java.nio.channels.FileChannel lockFileChannel
      • dbLock

        private java.nio.channels.FileLock dbLock
    • Constructor Detail

      • DirFile

        DirFile​(java.lang.String path)
        Construct a DirFile from a path name.
        Parameters:
        path - The path name.
      • DirFile

        DirFile​(java.lang.String directoryName,
                java.lang.String fileName)
        Construct a DirFile from a directory name and a file name.
        Parameters:
        directoryName - The directory part of the path name.
        fileName - The name of the file within the directory.
      • DirFile

        DirFile​(DirFile directoryName,
                java.lang.String fileName)
        Construct a DirFile from a directory name and a file name.
        Parameters:
        directoryName - The directory part of the path name.
        fileName - The name of the file within the directory.
    • Method Detail

      • getParentDir

        public StorageFile getParentDir()
        Get the name of the parent directory if this name includes a parent.
        Specified by:
        getParentDir in interface StorageFile
        Returns:
        An StorageFile denoting the parent directory of this StorageFile, if it has a parent, null if it does not have a parent.
      • getOutputStream

        public java.io.OutputStream getOutputStream()
                                             throws java.io.FileNotFoundException
        Creates an output stream from a file name.
        Specified by:
        getOutputStream in interface StorageFile
        Returns:
        an output stream suitable for writing to the file.
        Throws:
        java.io.FileNotFoundException - if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.
      • getOutputStream

        public java.io.OutputStream getOutputStream​(boolean append)
                                             throws java.io.FileNotFoundException
        Creates an output stream from a file name.
        Specified by:
        getOutputStream in interface StorageFile
        Parameters:
        append - If true then data will be appended to the end of the file, if it already exists. If false and a normal file already exists with this name the file will first be truncated to zero length.
        Returns:
        an output stream suitable for writing to the file.
        Throws:
        java.io.FileNotFoundException - if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.
      • getInputStream

        public java.io.InputStream getInputStream()
                                           throws java.io.FileNotFoundException
        Creates an input stream from a file name.
        Specified by:
        getInputStream in interface StorageFile
        Returns:
        an input stream suitable for reading from the file.
        Throws:
        java.io.FileNotFoundException - if the file is not found.
      • getExclusiveFileLock

        public int getExclusiveFileLock()
                                 throws StandardException
        Get an exclusive lock. This is used to ensure that two or more JVMs do not open the same database at the same time.
        Specified by:
        getExclusiveFileLock in interface StorageFile
        Returns:
        EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE if the lock cannot be acquired because it is already held.
        EXCLUSIVE_FILE_LOCK if the lock was successfully acquired.
        NO_FILE_LOCK_SUPPORT if the system does not support exclusive locks.
        Throws:
        StandardException
      • getRandomAccessFile

        public StorageRandomAccessFile getRandomAccessFile​(java.lang.String mode)
                                                    throws java.io.FileNotFoundException
        Get a random access (read/write) file.
        Specified by:
        getRandomAccessFile in interface StorageFile
        Parameters:
        mode - "r", "rw", "rws", or "rwd". The "rws" and "rwd" modes specify that the data is to be written to persistent store, consistent with the java.io.RandomAccessFile class ("synchronized" with the persistent storage, in the file system meaning of the word "synchronized"). However the implementation is not required to implement the "rws" or "rwd" modes. The implementation may treat "rws" and "rwd" as "rw". It is up to the user of this interface to call the StorageRandomAccessFile.sync method. If the "rws" or "rwd" modes are supported and the RandomAccessFile was opened in "rws" or "rwd" mode then the implementation of StorageRandomAccessFile.sync need not do anything.
        Returns:
        an object that can be used for random access to the file.
        Throws:
        java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw".
        java.io.FileNotFoundException - if the file exists but is a directory rather than a regular file, or cannot be opened or created for any other reason .
        See Also:
        java.io.RandomAccessFile
      • renameTo

        public boolean renameTo​(StorageFile newName)
        Rename the file denoted by this name. Note that StorageFile objects are immutable. This method renames the underlying file, it does not change this StorageFile object. The StorageFile object denotes the same name as before, however the exists() method will return false after the renameTo method executes successfully.

        It is not specified whether this method will succeed if a file already exists under the new name.

        Specified by:
        renameTo in interface StorageFile
        Parameters:
        newName - the new name.
        Returns:
        true if the rename succeeded, false if not.
      • deleteAll

        public boolean deleteAll()
        Deletes the named file and, if it is a directory, all the files and directories it contains.
        Specified by:
        deleteAll in interface StorageFile
        Returns:
        true if the named file or directory is successfully deleted, false if not
      • limitAccessToOwner

        public void limitAccessToOwner()
                                throws java.io.IOException
        Description copied from interface: StorageFile
        Use when creating a new file. By default, a file created in an underlying file system, if applicable, will have read and write access for the file owner unless the property derby.useDefaultFilePermissions is set to true.
        Specified by:
        limitAccessToOwner in interface StorageFile
        Throws:
        java.io.IOException