Package org.apache.derby.impl.io
Class BaseStorageFactory
java.lang.Object
org.apache.derby.impl.io.BaseStorageFactory
- All Implemented Interfaces:
StorageFactory
- Direct Known Subclasses:
CPStorageFactory
,DirStorageFactory
,JarStorageFactory
,URLStorageFactory
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.
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected String
protected String
(package private) String
protected String
private static final String
protected StorageFile
protected String
protected String
Fields inherited from interface org.apache.derby.io.StorageFactory
VERSION_NUMBER
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescription(package private) void
createTemporaryFile
(String prefix, String suffix) Create and returns a temporary file in temporary file system of database.(package private) abstract void
doInit()
Get the canonical name of the database.char
Get the pathname separator character used by the StorageFile implementation.int
Get the abstract name of the directory that holds temporary files.void
Classes implementing the StorageFactory interface must have a null constructor.boolean
isFast()
This method is used to determine whether the storage is fast (RAM based) or slow (disk based).boolean
Determine whether the database is read only.(package private) abstract StorageFile
newPersistentFile
(String path) Construct a persistent StorageFile from a path name.(package private) abstract StorageFile
newPersistentFile
(String directoryName, String fileName) Construct a persistent StorageFile from a directory and path name.(package private) abstract StorageFile
newPersistentFile
(StorageFile directoryName, String fileName) Construct a persistent StorageFile from a directory and path name.newStorageFile
(String path) Construct a StorageFile from a path name.newStorageFile
(String directoryName, String fileName) Construct a StorageFile from a directory and file name.newStorageFile
(StorageFile directoryName, String fileName) Construct a StorageFile from a directory and file name.private String
void
setCanonicalName
(String name) Set the canonicalName.void
shutdown()
The shutdown method is called during the normal shutdown of the database.boolean
Determine whether the storage supports random access.
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Field Details
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home
String home -
tempDir
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tempDirPath
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dataDirectory
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separatedDataDirectory
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uniqueName
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canonicalName
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TEMP_DIR_PREFIX
- See Also:
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Constructor Details
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BaseStorageFactory
BaseStorageFactory()Most of the initialization is done in the init method.
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Method Details
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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 interfaceStorageFactory
- 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).
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doInit
- Throws:
IOException
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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 interfaceStorageFactory
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getCanonicalName
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 interfaceStorageFactory
- Returns:
- the canonical name
- Throws:
IOException
- if an IO error occurred during the construction of the name.
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setCanonicalName
Set the canonicalName. May need adjustment due to DERBY-5096- Specified by:
setCanonicalName
in interfaceStorageFactory
- Parameters:
name
- uniquely identifiable name for this database
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newStorageFile
Construct a StorageFile from a path name.- Specified by:
newStorageFile
in interfaceStorageFactory
- Parameters:
path
- The path name of the file- Returns:
- A corresponding StorageFile object
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newStorageFile
Construct a StorageFile from a directory and file name.- Specified by:
newStorageFile
in interfaceStorageFactory
- Parameters:
directoryName
- The directory part of the path name.fileName
- The name of the file within the directory.- Returns:
- A corresponding StorageFile object
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newStorageFile
Construct a StorageFile from a directory and file name.- Specified by:
newStorageFile
in interfaceStorageFactory
- Parameters:
directoryName
- The directory part of the path name.fileName
- The name of the file within the directory.- Returns:
- A corresponding StorageFile object
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newPersistentFile
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
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newPersistentFile
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 nullfileName
- The name of the file within the directory. Guaranteed not to be null.- Returns:
- A corresponding StorageFile object
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newPersistentFile
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
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getSeparator
public char getSeparator()Get the pathname separator character used by the StorageFile implementation.- Specified by:
getSeparator
in interfaceStorageFactory
- Returns:
- the pathname separator character. (Normally '/' or '\').
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getTempDir
Get the abstract name of the directory that holds temporary files.- Specified by:
getTempDir
in interfaceStorageFactory
- Returns:
- a directory name
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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 interfaceStorageFactory
- Returns:
- true if the storage is fast, false if it is slow.
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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 interfaceStorageFactory
- Returns:
- true if the storage is read only, false if it is writable.
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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 interfaceStorageFactory
- Returns:
- true if the storage supports random access, false if it is writable.
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createTempDir
- Throws:
IOException
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readOnlyTempRoot
- Throws:
IOException
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getStorageFactoryVersion
public int getStorageFactoryVersion()- Specified by:
getStorageFactoryVersion
in interfaceStorageFactory
- Returns:
- the StorageFactory version supported by this implementation
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createTemporaryFile
Create and returns a temporary file in temporary file system of database.- Specified by:
createTemporaryFile
in interfaceStorageFactory
- Parameters:
prefix
- String to prefix the random name generator.suffix
- String to suffix the random name generator.- Returns:
- StorageFile
- Throws:
IOException
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