Class BaseStorageFactory

java.lang.Object
org.apache.derby.impl.io.BaseStorageFactory
All Implemented Interfaces:
StorageFactory
Direct Known Subclasses:
CPStorageFactory, DirStorageFactory, JarStorageFactory, URLStorageFactory

abstract class BaseStorageFactory extends Object implements StorageFactory
This class provides a base for implementations of the StorageFactory interface. It is used by the database engine to access persistent data and transaction logs under the directory (default) subsubprotocol.
  • Field Details

    • home

      String home
    • tempDir

      protected StorageFile tempDir
    • tempDirPath

      protected String tempDirPath
    • dataDirectory

      protected String dataDirectory
    • separatedDataDirectory

      protected String separatedDataDirectory
    • uniqueName

      protected String uniqueName
    • canonicalName

      protected String canonicalName
    • TEMP_DIR_PREFIX

      private static final String TEMP_DIR_PREFIX
      See Also:
  • Constructor Details

    • BaseStorageFactory

      BaseStorageFactory()
      Most of the initialization is done in the init method.
  • Method Details

    • init

      public void init(String home, String databaseName, String tempDirName, String uniqueName) throws IOException
      Classes implementing the StorageFactory interface must have a null constructor. This method is called when the database is booted up to initialize the class. It should perform all actions necessary to start the basic storage, such as creating a temporary file directory. The init method will be called once, before any other method is called, and will not be called again.
      Specified by:
      init in interface StorageFactory
      Parameters:
      home - The name of the directory containing the database. It comes from the system.home system property. It may be null. A storage factory may decide to ignore this parameter. (For instance the classpath storage factory ignores it.
      databaseName - The name of the database (directory). All relative pathnames are relative to this directory. If null then the storage factory will only be used to deal with the directory containing the databases.
      tempDirName - The name of the temporary file directory set in properties. If null then a default directory should be used. Each database should get a separate temporary file directory within this one to avoid collisions.
      uniqueName - A unique name that can be used to create the temporary file directory for this database.
      Throws:
      IOException - on an error (unexpected).
    • doInit

      abstract void doInit() throws IOException
      Throws:
      IOException
    • shutdown

      public void shutdown()
      Description copied from interface: StorageFactory
      The shutdown method is called during the normal shutdown of the database. However, the database engine cannot guarantee that shutdown will be called. If the JVM terminates abnormally then it will not be called.
      Specified by:
      shutdown in interface StorageFactory
    • getCanonicalName

      public String getCanonicalName() throws IOException
      Get the canonical name of the database. This is a name that uniquely identifies it. It is system dependent. The normal, disk based implementation uses method java.io.File.getCanonicalPath on the directory holding the database to construct the canonical name.
      Specified by:
      getCanonicalName in interface StorageFactory
      Returns:
      the canonical name
      Throws:
      IOException - if an IO error occurred during the construction of the name.
    • setCanonicalName

      public void setCanonicalName(String name)
      Set the canonicalName. May need adjustment due to DERBY-5096
      Specified by:
      setCanonicalName in interface StorageFactory
      Parameters:
      name - uniquely identifiable name for this database
    • newStorageFile

      public StorageFile newStorageFile(String path)
      Construct a StorageFile from a path name.
      Specified by:
      newStorageFile in interface StorageFactory
      Parameters:
      path - The path name of the file
      Returns:
      A corresponding StorageFile object
    • newStorageFile

      public StorageFile newStorageFile(String directoryName, String fileName)
      Construct a StorageFile from a directory and file name.
      Specified by:
      newStorageFile in interface StorageFactory
      Parameters:
      directoryName - The directory part of the path name.
      fileName - The name of the file within the directory.
      Returns:
      A corresponding StorageFile object
    • newStorageFile

      public StorageFile newStorageFile(StorageFile directoryName, String fileName)
      Construct a StorageFile from a directory and file name.
      Specified by:
      newStorageFile in interface StorageFactory
      Parameters:
      directoryName - The directory part of the path name.
      fileName - The name of the file within the directory.
      Returns:
      A corresponding StorageFile object
    • newPersistentFile

      abstract StorageFile newPersistentFile(String path)
      Construct a persistent StorageFile from a path name.
      Parameters:
      path - The path name of the file. Guaranteed not to be in the temporary file directory. If null then the database directory should be returned.
      Returns:
      A corresponding StorageFile object
    • newPersistentFile

      abstract StorageFile newPersistentFile(String directoryName, String fileName)
      Construct a persistent StorageFile from a directory and path name.
      Parameters:
      directoryName - The path name of the directory. Guaranteed not to be in the temporary file directory. Guaranteed not to be null
      fileName - The name of the file within the directory. Guaranteed not to be null.
      Returns:
      A corresponding StorageFile object
    • newPersistentFile

      abstract StorageFile newPersistentFile(StorageFile directoryName, String fileName)
      Construct a persistent StorageFile from a directory and path name.
      Parameters:
      directoryName - The path name of the directory. Guaranteed not to be to be null. Guaranteed to be created by a call to one of the newPersistentFile methods.
      fileName - The name of the file within the directory. Guaranteed not to be null.
      Returns:
      A corresponding StorageFile object
    • getSeparator

      public char getSeparator()
      Get the pathname separator character used by the StorageFile implementation.
      Specified by:
      getSeparator in interface StorageFactory
      Returns:
      the pathname separator character. (Normally '/' or '\').
    • getTempDir

      public StorageFile getTempDir()
      Get the abstract name of the directory that holds temporary files.
      Specified by:
      getTempDir in interface StorageFactory
      Returns:
      a directory name
    • isFast

      public boolean isFast()
      This method is used to determine whether the storage is fast (RAM based) or slow (disk based). It may be used by the database engine to determine the default size of the page cache.
      Specified by:
      isFast in interface StorageFactory
      Returns:
      true if the storage is fast, false if it is slow.
    • isReadOnlyDatabase

      public boolean isReadOnlyDatabase()
      Description copied from interface: StorageFactory
      Determine whether the database is read only. The database engine supports read-only databases, even in file systems that are writable.
      Specified by:
      isReadOnlyDatabase in interface StorageFactory
      Returns:
      true if the storage is read only, false if it is writable.
    • supportsRandomAccess

      public boolean supportsRandomAccess()
      Determine whether the storage supports random access. If random access is not supported then it will only be accessed using InputStreams and OutputStreams (if the database is writable).
      Specified by:
      supportsRandomAccess in interface StorageFactory
      Returns:
      true if the storage supports random access, false if it is writable.
    • createTempDir

      void createTempDir() throws IOException
      Throws:
      IOException
    • readOnlyTempRoot

      private String readOnlyTempRoot() throws IOException
      Throws:
      IOException
    • getStorageFactoryVersion

      public int getStorageFactoryVersion()
      Specified by:
      getStorageFactoryVersion in interface StorageFactory
      Returns:
      the StorageFactory version supported by this implementation
    • createTemporaryFile

      public StorageFile createTemporaryFile(String prefix, String suffix) throws IOException
      Create and returns a temporary file in temporary file system of database.
      Specified by:
      createTemporaryFile in interface StorageFactory
      Parameters:
      prefix - String to prefix the random name generator.
      suffix - String to suffix the random name generator.
      Returns:
      StorageFile
      Throws:
      IOException