@NotThreadSafe public class BufferedReadOnlyFile extends DecoratingReadOnlyFile
ReadOnlyFile implementation which provides buffered random read
only access to another ReadOnlyFile.
Note: This class implements its own virtual file pointer.
Thus, if you would like to access the underlying ReadOnlyFile
again after you have finished working with an instance of this class,
you should synchronize their file pointers using the pattern as described
in DecoratingReadOnlyFile.
| Modifier and Type | Field and Description |
|---|---|
private boolean |
closed |
private long |
fp
The virtual file pointer in the file data.
|
private long |
length |
private byte[] |
window
The buffer window to the file data.
|
static int |
WINDOW_LEN
The default buffer length of the window to the file.
|
private long |
windowOff
The current offset in the read only file where the buffer window starts.
|
delegate| Modifier | Constructor and Description |
|---|---|
|
BufferedReadOnlyFile(File file)
Creates a new instance of
BufferedReadOnlyFile. |
|
BufferedReadOnlyFile(File file,
int windowLen)
Creates a new instance of
BufferedReadOnlyFile. |
|
BufferedReadOnlyFile(ReadOnlyFile rof)
Creates a new instance of
BufferedReadOnlyFile. |
private |
BufferedReadOnlyFile(ReadOnlyFile rof,
File file,
int windowLen) |
|
BufferedReadOnlyFile(ReadOnlyFile rof,
int windowLen)
Creates a new instance of
BufferedReadOnlyFile. |
| Modifier and Type | Method and Description |
|---|---|
private void |
assertOpen()
Asserts that this file is open.
|
void |
close()
Closes this read only file.
|
long |
getFilePointer()
Returns the current byte position in the file as a zero-based index.
|
private void |
invalidateWindow()
Forces the window to be reloaded on the next call to
positionWindow(). |
long |
length()
Returns the length of the file in bytes.
|
protected static long |
max(long a,
long b)
Returns the greater parameter.
|
protected static long |
min(long a,
long b)
Returns the smaller parameter.
|
private void |
positionWindow()
Positions the window so that the block containing the current virtual
file pointer in the encrypted file is entirely contained in it.
|
int |
read()
Reads and returns the next byte or -1 if the end of the file has been
reached.
|
int |
read(byte[] buf,
int off,
int len)
Reads up to
len bytes of data from this read only file into
the given array. |
void |
seek(long fp)
Sets the current byte position in the file as a zero-based index at
which the next read occurs.
|
toStringread, readFully, readFullypublic static final int WINDOW_LEN
private long length
private long fp
private long windowOff
private final byte[] window
private boolean closed
public BufferedReadOnlyFile(File file) throws NullPointerException, FileNotFoundException, IOException
BufferedReadOnlyFile.file - The file to read.NullPointerException - If any of the parameters is null.FileNotFoundException - If the file cannot get opened for reading.IOException - On any other I/O related issue.public BufferedReadOnlyFile(File file, int windowLen) throws NullPointerException, FileNotFoundException, IOException
BufferedReadOnlyFile.file - The file to read.windowLen - The size of the buffer window in bytes.NullPointerException - If any of the parameters is null.FileNotFoundException - If the file cannot get opened for reading.IOException - On any other I/O related issue.public BufferedReadOnlyFile(ReadOnlyFile rof) throws NullPointerException, FileNotFoundException, IOException
BufferedReadOnlyFile.rof - The read only file to read.NullPointerException - If any of the parameters is null.FileNotFoundException - If the file cannot get opened for reading.IOException - On any other I/O related issue.public BufferedReadOnlyFile(ReadOnlyFile rof, int windowLen) throws NullPointerException, FileNotFoundException, IOException
BufferedReadOnlyFile.rof - The read only file to read.windowLen - The size of the buffer window in bytes.NullPointerException - If any of the parameters is null.FileNotFoundException - If the file cannot get opened for reading.IOException - On any other I/O related issue.private BufferedReadOnlyFile(ReadOnlyFile rof, File file, int windowLen) throws NullPointerException, FileNotFoundException, IOException
protected static long min(long a,
long b)
protected static long max(long a,
long b)
public long length()
throws IOException
ReadOnlyFilelength in interface ReadOnlyFilelength in class DecoratingReadOnlyFileIOExceptionpublic long getFilePointer()
throws IOException
ReadOnlyFilegetFilePointer in interface ReadOnlyFilegetFilePointer in class DecoratingReadOnlyFileIOExceptionpublic void seek(long fp)
throws IOException
ReadOnlyFileDefaultReadOnlyFile subclass
RandomAccessFile passes "r" as a parameter to
the superclass constructor.
With Sun's JSE implementation, on the Windows platform this
implementation allows to seek past the end of file, but on the Linux
platform it doesn't.seek in interface ReadOnlyFileseek in class DecoratingReadOnlyFilefp - The current byte position as a zero-based index.IOException - If pos is less than 0 or if
an I/O error occurs.public int read()
throws IOException
ReadOnlyFileread in interface ReadOnlyFileread in class DecoratingReadOnlyFileIOExceptionpublic int read(byte[] buf,
int off,
int len)
throws IOException
ReadOnlyFilelen bytes of data from this read only file into
the given array.
This method blocks until at least one byte of input is available.read in interface ReadOnlyFileread in class DecoratingReadOnlyFilebuf - The buffer to fill with data.off - The start offset of the data.len - The maximum number of bytes to read.-1 if there is
no more data because the end of the file has been reached.IOException - On any I/O related issue.public void close()
throws IOException
DecoratingReadOnlyFile.delegate to null.close in interface ReadOnlyFileclose in interface Closeableclose in interface AutoCloseableclose in class DecoratingReadOnlyFileIOExceptionprivate void assertOpen()
throws IOException
IOException - If the preconditions do not hold.private void positionWindow()
throws IOException
IOException - On any I/O related issue.
The window is invalidated in this case.private void invalidateWindow()
positionWindow().Copyright © 2005-2011 Schlichtherle IT Services. All Rights Reserved.