Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.io.StorageFile

Modifier and Type	Field and Description
public static final int	EXCLUSIVE_FILE_LOCK
public static final int	EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE
public static final int	NO_FILE_LOCK_SUPPORT

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: true if the file exists and is writable, false if not. canWrite() Determine whether the named file is writable.
public boolean	Returns: true if this thread's invocation of createNewFile successfully created the named file; false if not, i.e. false if the named file already exists or if another concurrent thread created it. createNewFile() If the named file does not already exist then create it as an empty normal file.
public boolean	Returns: true if the named file or directory is successfully deleted, false if not delete() Deletes the named file or empty directory.
public boolean	Returns: true if the named file or directory is successfully deleted, false if not deleteAll() Deletes the named file and, if it is a directory, all the files and directories it contains.
public boolean	Returns: true if the named file exists, false if not. exists() Tests whether the named file exists.
public String	Returns: The pathname as a string. getCanonicalPath() Converts this StorageFile into a canonical pathname string.
public int	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. getExclusiveFileLock() Get an exclusive lock with this name.
public InputStream	Returns: an input stream suitable for reading from the file. getInputStream() Creates an input stream from a file name.
public String	Returns: The last segment in the path name, "" if the path name sequence is empty. getName()
public OutputStream	Returns: an output stream suitable for writing to the file. getOutputStream() Creates an output stream from a file name.
public OutputStream	Returns: an output stream suitable for writing to the file. getOutputStream(boolean 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. append) Creates an output stream from a file name.
public StorageFile	Returns: An StorageFile denoting the parent directory of this StorageFile, if it has a parent, null if it does not have a parent. getParentDir() Get the name of the parent directory if this name includes a parent.
public String	Returns: The pathname as a string. getPath() Converts this StorageFile into a pathname string.
public StorageRandomAccessFile	Returns: an object that can be used for random access to the file. getRandomAccessFile(String "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. If the "rws" andr "rwd" modes are supported then the supportsRws() method of the StorageFactory returns true. If supportsRws() returns false then 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 necessary. However, 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. mode) Get a random access file.
public boolean	Returns: true if named file exists and is a directory, false if not. The return value is undefined if the storage is read-only. isDirectory() Tests whether the named file is a directory, or not.
public void	limitAccessToOwner() Use when creating a new file.
public String[]	Returns: An array of the names of the files and directories in this directory denoted by this abstract pathname. The returned array will have length 0 if this directory is empty. Returns null if this StorageFile is not a directory, or if an I/O error occurs. The return value is undefined if the database is read-only. list() Get the names of all files and sub-directories in the directory named by this path name.
public boolean	Returns: true if the directory was created; false if not. mkdir() Creates the named directory.
public boolean	Returns: true if the directory was created, false if not mkdirs() Creates the named directory, and all nonexistent parent directories.
public void	releaseExclusiveFileLock() Release the resource associated with an earlier acquired exclusive lock releaseExclusiveFileLock() may delete the file
public boolean	Returns: true if the rename succeeded, false if not. renameTo(StorageFile the new name. newName) Rename the file denoted by this name.
public boolean	Returns: true if the named file or directory was made read-only, or it already was read-only; false if not. setReadOnly() Make the named file or directory read-only.

EXCLUSIVE_FILE_LOCK	back to summary
public static final int EXCLUSIVE_FILE_LOCK

EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE	back to summary
public static final int EXCLUSIVE_FILE_LOCK_NOT_AVAILABLE

NO_FILE_LOCK_SUPPORT	back to summary
public static final int NO_FILE_LOCK_SUPPORT

Method Detail

canWrite	back to summary
public boolean canWrite() Determine whether the named file is writable. Returns:boolean true if the file exists and is writable, false if not.

canWrite

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public boolean canWrite()

Determine whether the named file is writable.

Returns:boolean: true if the file exists and is writable, false if not.

createNewFile	back to summary
public boolean createNewFile() throws IOException If the named file does not already exist then create it as an empty normal file. The implementation must synchronize with other threads accessing the same file (in the same or a different process). If two threads both attempt to create a file with the same name at the same time then at most one should succeed. Returns:boolean true if this thread's invocation of createNewFile successfully created the named file; false if not, i.e. false if the named file already exists or if another concurrent thread created it. Exceptions IOException: - If the directory does not exist or some other I/O error occurred

createNewFile

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public boolean createNewFile() throws IOException

If the named file does not already exist then create it as an empty normal file. The implementation must synchronize with other threads accessing the same file (in the same or a different process). If two threads both attempt to create a file with the same name at the same time then at most one should succeed.

Returns:boolean

true if this thread's invocation of createNewFile successfully created the named file; false if not, i.e. false if the named file already exists or if another concurrent thread created it.

Exceptions

IOException:: - If the directory does not exist or some other I/O error occurred

delete	back to summary
public boolean delete() Deletes the named file or empty directory. This method does not delete non-empty directories. Returns:boolean true if the named file or directory is successfully deleted, false if not

delete

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public boolean delete()

Deletes the named file or empty directory. This method does not delete non-empty directories.

Returns:boolean: true if the named file or directory is successfully deleted, false if not

deleteAll	back to summary
public boolean deleteAll() Deletes the named file and, if it is a directory, all the files and directories it contains. Returns:boolean true if the named file or directory is successfully deleted, false if not

deleteAll

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public boolean deleteAll()

Deletes the named file and, if it is a directory, all the files and directories it contains.

Returns:boolean: true if the named file or directory is successfully deleted, false if not

exists	back to summary
public boolean exists() Tests whether the named file exists. Returns:boolean true if the named file exists, false if not.

exists

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public boolean exists()

Tests whether the named file exists.

Returns:boolean: true if the named file exists, false if not.

getCanonicalPath	back to summary
public String getCanonicalPath() throws IOException Converts this StorageFile into a canonical pathname string. The form of the canonical path is system dependent. Returns:String The pathname as a string. Exceptions IOException: if an I/O error occurred while finding the canonical name

getCanonicalPath

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public String getCanonicalPath() throws IOException

Converts this StorageFile into a canonical pathname string. The form of the canonical path is system dependent.

Returns:String

The pathname as a string.

Exceptions

IOException:: if an I/O error occurred while finding the canonical name

getExclusiveFileLock	back to summary
public int getExclusiveFileLock() throws StandardException Get an exclusive lock with this name. This is used to ensure that two or more JVMs do not open the same database at the same time. ny StorageFile that has getExclusiveFileLock() called on it is not intended to be read from or written to. It's sole purpose is to provide a locked entity to avoid multiple instances of Derby accessing the same database. getExclusiveFileLock() may delete or overwrite any existing file. Returns:int 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.

getExclusiveFileLock

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public int getExclusiveFileLock() throws StandardException

Get an exclusive lock with this name. This is used to ensure that two or more JVMs do not open the same database at the same time. ny StorageFile that has getExclusiveFileLock() called on it is not intended to be read from or written to. It's sole purpose is to provide a locked entity to avoid multiple instances of Derby accessing the same database. getExclusiveFileLock() may delete or overwrite any existing file.

Returns:int: 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.

getInputStream	back to summary
public InputStream getInputStream() throws FileNotFoundException Creates an input stream from a file name. Returns:InputStream an input stream suitable for reading from the file. Exceptions FileNotFoundException: if the file is not found.

getInputStream

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public InputStream getInputStream() throws FileNotFoundException

Creates an input stream from a file name.

Returns:InputStream

an input stream suitable for reading from the file.

Exceptions

FileNotFoundException:: if the file is not found.

getName	back to summary
public String getName() Returns:String The last segment in the path name, "" if the path name sequence is empty.

getOutputStream	back to summary
public OutputStream getOutputStream() throws FileNotFoundException Creates an output stream from a file name. If a normal file already exists with this name it will first be truncated to zero length. Returns:OutputStream an output stream suitable for writing to the file. Exceptions 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

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public OutputStream getOutputStream() throws FileNotFoundException

Creates an output stream from a file name. If a normal file already exists with this name it will first be truncated to zero length.

Returns:OutputStream

an output stream suitable for writing to the file.

Exceptions

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	back to summary
public OutputStream getOutputStream(boolean append) throws FileNotFoundException Creates an output stream from a file name. Parameters append:boolean 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:OutputStream an output stream suitable for writing to the file. Exceptions 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

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public OutputStream getOutputStream(boolean append) throws FileNotFoundException

Creates an output stream from a file name.

Parameters

append:boolean: 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:OutputStream

an output stream suitable for writing to the file.

Exceptions

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.

getParentDir	back to summary
public StorageFile getParentDir() Get the name of the parent directory if this name includes a parent. Returns:StorageFile An StorageFile denoting the parent directory of this StorageFile, if it has a parent, null if it does not have a parent.

getParentDir

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public StorageFile getParentDir()

Get the name of the parent directory if this name includes a parent.

Returns:StorageFile: An StorageFile denoting the parent directory of this StorageFile, if it has a parent, null if it does not have a parent.

getPath back to summary

getPath	back to summary
public String getPath() Converts this StorageFile into a pathname string. The character returned by StorageFactory.getSeparator() is used to separate the directory and file names in the sequence. The returned path may include the database directory. Therefore it cannot be directly used to make an StorageFile equivalent to this one. Returns:String The pathname as a string. See Also `StorageFactory#getSeparator`

public String getPath()

Converts this StorageFile into a pathname string. The character returned by StorageFactory.getSeparator() is used to separate the directory and file names in the sequence.

The returned path may include the database directory. Therefore it cannot be directly used to make an StorageFile equivalent to this one.

Returns:String: The pathname as a string.
See Also: StorageFactory#getSeparator

getRandomAccessFile	back to summary
public StorageRandomAccessFile getRandomAccessFile(String mode) throws FileNotFoundException Get a random access file. This method is not called if the StorageFactory is read only. It is unspecified if the StorageFactory that created it is not a WritableStorageFactory. Parameters mode:String "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. If the "rws" andr "rwd" modes are supported then the supportsRws() method of the StorageFactory returns true. If supportsRws() returns false then 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 necessary. However, 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:StorageRandomAccessFile an object that can be used for random access to the file. Exceptions FileNotFoundException: if the file exists but is a directory rather than a regular file, or cannot be opened or created for any other reason . IllegalArgumentException: if the mode argument is not equal to one of "r", "rw", "rws", or "rwd". See Also java.io.RandomAccessFile

getRandomAccessFile

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public StorageRandomAccessFile getRandomAccessFile(String mode) throws FileNotFoundException

Get a random access file. This method is not called if the StorageFactory is read only. It is unspecified if the StorageFactory that created it is not a WritableStorageFactory.

Parameters

mode:String: "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. If the "rws" andr "rwd" modes are supported then the supportsRws() method of the StorageFactory returns true. If supportsRws() returns false then 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 necessary. However, 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:StorageRandomAccessFile

an object that can be used for random access to the file.

Exceptions

FileNotFoundException:: if the file exists but is a directory rather than a regular file, or cannot be opened or created for any other reason .
IllegalArgumentException:: if the mode argument is not equal to one of "r", "rw", "rws", or "rwd".

See Also

java.io.RandomAccessFile

isDirectory	back to summary
public boolean isDirectory() Tests whether the named file is a directory, or not. This is only called in writable storage factories. Returns:boolean true if named file exists and is a directory, false if not. The return value is undefined if the storage is read-only.

isDirectory

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public boolean isDirectory()

Tests whether the named file is a directory, or not. This is only called in writable storage factories.

Returns:boolean: true if named file exists and is a directory, false if not. The return value is undefined if the storage is read-only.

limitAccessToOwner	back to summary
public void limitAccessToOwner() throws IOException 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`.

list	back to summary
public String[] list() Get the names of all files and sub-directories in the directory named by this path name. This method is only used in a writable database. Returns:String[] An array of the names of the files and directories in this directory denoted by this abstract pathname. The returned array will have length 0 if this directory is empty. Returns null if this StorageFile is not a directory, or if an I/O error occurs. The return value is undefined if the database is read-only.

list

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public String[] list()

Get the names of all files and sub-directories in the directory named by this path name. This method is only used in a writable database.

Returns:String[]: An array of the names of the files and directories in this directory denoted by this abstract pathname. The returned array will have length 0 if this directory is empty. Returns null if this StorageFile is not a directory, or if an I/O error occurs. The return value is undefined if the database is read-only.

mkdir	back to summary
public boolean mkdir() Creates the named directory. Returns:boolean true if the directory was created; false if not.

mkdir

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public boolean mkdir()

Creates the named directory.

Returns:boolean: true if the directory was created; false if not.

mkdirs	back to summary
public boolean mkdirs() Creates the named directory, and all nonexistent parent directories. Returns:boolean true if the directory was created, false if not

mkdirs

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public boolean mkdirs()

Creates the named directory, and all nonexistent parent directories.

Returns:boolean: true if the directory was created, false if not

releaseExclusiveFileLock back to summary

releaseExclusiveFileLock	back to summary
public void releaseExclusiveFileLock() Release the resource associated with an earlier acquired exclusive lock releaseExclusiveFileLock() may delete the file See Also `getExclusiveFileLock`

public void releaseExclusiveFileLock()

Release the resource associated with an earlier acquired exclusive lock releaseExclusiveFileLock() may delete the file

See Also: getExclusiveFileLock

renameTo	back to summary
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. Parameters newName:StorageFile the new name. Returns:boolean true if the rename succeeded, false if not.

renameTo

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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.

Parameters

newName:StorageFile: the new name.

Returns:boolean

true if the rename succeeded, false if not.

setReadOnly	back to summary
public boolean setReadOnly() Make the named file or directory read-only. This interface does not specify whether this also makes the file undeletable. Returns:boolean true if the named file or directory was made read-only, or it already was read-only; false if not.

setReadOnly

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public boolean setReadOnly()

Make the named file or directory read-only. This interface does not specify whether this also makes the file undeletable.

Returns:boolean: true if the named file or directory was made read-only, or it already was read-only; false if not.

public Interface StorageFile

Field Summary

Method Summary

Field Detail

Method Detail