Class Directory

    • Constructor Summary

      Constructors 
      Constructor Description
      Directory()  
    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      abstract void close()
      Closes the directory.
      void copyFrom​(Directory from, java.lang.String src, java.lang.String dest, IOContext context)
      Copies an existing src file from directory from to a non-existent file dest in this directory.
      abstract IndexOutput createOutput​(java.lang.String name, IOContext context)
      Creates a new, empty file in the directory and returns an IndexOutput instance for appending data to this file.
      abstract IndexOutput createTempOutput​(java.lang.String prefix, java.lang.String suffix, IOContext context)
      Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file.
      abstract void deleteFile​(java.lang.String name)
      Removes an existing file in the directory.
      protected void ensureOpen()
      Ensures this directory is still open.
      abstract long fileLength​(java.lang.String name)
      Returns the byte length of a file in the directory.
      abstract java.util.Set<java.lang.String> getPendingDeletions()
      Returns a set of files currently pending deletion in this directory.
      protected static java.lang.String getTempFileName​(java.lang.String prefix, java.lang.String suffix, long counter)
      Creates a file name for a temporary file.
      abstract java.lang.String[] listAll()
      Returns names of all files stored in this directory.
      abstract Lock obtainLock​(java.lang.String name)
      Acquires and returns a Lock for a file with the given name.
      ChecksumIndexInput openChecksumInput​(java.lang.String name, IOContext context)
      Opens a checksum-computing stream for reading an existing file.
      abstract IndexInput openInput​(java.lang.String name, IOContext context)
      Opens a stream for reading an existing file.
      abstract void rename​(java.lang.String source, java.lang.String dest)
      Renames source file to dest file where dest must not already exist in the directory.
      abstract void sync​(java.util.Collection<java.lang.String> names)
      Ensures that any writes to these files are moved to stable storage (made durable).
      abstract void syncMetaData()
      Ensures that directory metadata, such as recent file renames, are moved to stable storage.
      java.lang.String toString()  
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Constructor Detail

      • Directory

        public Directory()
    • Method Detail

      • listAll

        public abstract java.lang.String[] listAll()
                                            throws java.io.IOException
        Returns names of all files stored in this directory. The output must be in sorted (UTF-16, java's String.compareTo(java.lang.String)) order.
        Throws:
        java.io.IOException - in case of I/O error
      • deleteFile

        public abstract void deleteFile​(java.lang.String name)
                                 throws java.io.IOException
        Removes an existing file in the directory. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
        Parameters:
        name - the name of an existing file.
        Throws:
        java.io.IOException - in case of I/O error
      • fileLength

        public abstract long fileLength​(java.lang.String name)
                                 throws java.io.IOException
        Returns the byte length of a file in the directory. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
        Parameters:
        name - the name of an existing file.
        Throws:
        java.io.IOException - in case of I/O error
      • createOutput

        public abstract IndexOutput createOutput​(java.lang.String name,
                                                 IOContext context)
                                          throws java.io.IOException
        Creates a new, empty file in the directory and returns an IndexOutput instance for appending data to this file. This method must throw FileAlreadyExistsException if the file already exists.
        Parameters:
        name - the name of the file to create.
        Throws:
        java.io.IOException - in case of I/O error
      • createTempOutput

        public abstract IndexOutput createTempOutput​(java.lang.String prefix,
                                                     java.lang.String suffix,
                                                     IOContext context)
                                              throws java.io.IOException
        Creates a new, empty, temporary file in the directory and returns an IndexOutput instance for appending data to this file. The temporary file name (accessible via IndexOutput.getName()) will start with prefix, end with suffix and have a reserved file extension .tmp.
        Throws:
        java.io.IOException
      • sync

        public abstract void sync​(java.util.Collection<java.lang.String> names)
                           throws java.io.IOException
        Ensures that any writes to these files are moved to stable storage (made durable). Lucene uses this to properly commit changes to the index, to prevent a machine/OS crash from corrupting the index.
        Throws:
        java.io.IOException
        See Also:
        syncMetaData()
      • syncMetaData

        public abstract void syncMetaData()
                                   throws java.io.IOException
        Ensures that directory metadata, such as recent file renames, are moved to stable storage.
        Throws:
        java.io.IOException
        See Also:
        sync(Collection)
      • rename

        public abstract void rename​(java.lang.String source,
                                    java.lang.String dest)
                             throws java.io.IOException
        Renames source file to dest file where dest must not already exist in the directory. It is permitted for this operation to not be truly atomic, for example both source and dest can be visible temporarily in listAll(). However, the implementation of this method must ensure the content of dest appears as the entire source atomically. So once dest is visible for readers, the entire content of previous source is visible. This method is used by IndexWriter to publish commits.
        Throws:
        java.io.IOException
      • openInput

        public abstract IndexInput openInput​(java.lang.String name,
                                             IOContext context)
                                      throws java.io.IOException
        Opens a stream for reading an existing file. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
        Parameters:
        name - the name of an existing file.
        Throws:
        java.io.IOException - in case of I/O error
      • openChecksumInput

        public ChecksumIndexInput openChecksumInput​(java.lang.String name,
                                                    IOContext context)
                                             throws java.io.IOException
        Opens a checksum-computing stream for reading an existing file. This method must throw either NoSuchFileException or FileNotFoundException if name points to a non-existing file.
        Parameters:
        name - the name of an existing file.
        Throws:
        java.io.IOException - in case of I/O error
      • obtainLock

        public abstract Lock obtainLock​(java.lang.String name)
                                 throws java.io.IOException
        Acquires and returns a Lock for a file with the given name.
        Parameters:
        name - the name of the lock file
        Throws:
        LockObtainFailedException - (optional specific exception) if the lock could not be obtained because it is currently held elsewhere.
        java.io.IOException - if any i/o error occurs attempting to gain the lock
      • close

        public abstract void close()
                            throws java.io.IOException
        Closes the directory.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Throws:
        java.io.IOException
      • copyFrom

        public void copyFrom​(Directory from,
                             java.lang.String src,
                             java.lang.String dest,
                             IOContext context)
                      throws java.io.IOException
        Copies an existing src file from directory from to a non-existent file dest in this directory.
        Throws:
        java.io.IOException
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
      • getPendingDeletions

        public abstract java.util.Set<java.lang.String> getPendingDeletions()
                                                                     throws java.io.IOException
        Returns a set of files currently pending deletion in this directory.
        Throws:
        java.io.IOException
      • getTempFileName

        protected static java.lang.String getTempFileName​(java.lang.String prefix,
                                                          java.lang.String suffix,
                                                          long counter)
        Creates a file name for a temporary file. The name will start with prefix, end with suffix and have a reserved file extension .tmp.
        See Also:
        createTempOutput(String, String, IOContext)