PostgreSQL JDBC Driver 42.7.2 · org.postgresql.largeobject.BlobInputStream

Field Summary

Modifier and Type	Field and Description
private long	absolutePosition The absolute position.
private @Nullable byte[]	buffer Buffer used to improve performance.
private int	bufferPosition Position within buffer.
pack-priv static final int	DEFAULT_MAX_BUFFER_SIZE
pack-priv static final int	INITIAL_BUFFER_SIZE
private int	lastBufferSize The amount of bytes to read on the next read.
private final long	limit The limit.
private @Nullable LargeObject	lo The parent LargeObject.
private final ResourceLock	lock
private long	markPosition The mark position.
private final int	maxBufferSize The buffer size.

Constructor Summary

Access	Constructor and Description
public	BlobInputStream(LargeObject LargeObject to read from lo)
public	BlobInputStream(LargeObject LargeObject to read from lo, int buffer size bsize)
public	BlobInputStream(LargeObject LargeObject to read from lo, int buffer size bsize, long max number of bytes to read limit)

Method Summary

Modifier and Type	Method and Description
public void	close() Overrides java.io.InputStream.close. Implements java.io.Closeable.close. Closes this input stream and releases any system resources associated with the stream.
private LargeObject	getLo()
private int	Returns: next buffer size or `maxBufferSize` if the buffer should not be increased getNextBufferSize(int estimated read request len) Computes the next buffer size to use for reading data from the large object.
public void	mark(int the maximum limit of bytes that can be read before the mark position becomes invalid. readlimit) Overrides java.io.InputStream.mark. Marks the current position in this input stream.
public boolean	Returns: `true` if this true type supports the mark and reset method; `false` otherwise. markSupported() Overrides java.io.InputStream.markSupported. Tests if this input stream supports the `mark` and `reset` methods.
public int	read() Implements abstract java.io.InputStream.read. The minimum required to implement input stream.
public int	read(byte[] the buffer into which the data is read. dest, int the start offset in array `b` at which the data is written. off, int the maximum number of bytes to read. len) Overrides java.io.InputStream.read. Reads up to `len` bytes of data from the input stream into an array of bytes.
public void	reset() Overrides java.io.InputStream.reset. Repositions this stream to the position at the time the `mark` method was last called on this input stream.

Inherited from java.io.InputStream:: available nullInputStream read readAllBytes readNBytes readNBytes skip skipNBytes transferTo

Field Detail

absolutePosition	back to summary
private long absolutePosition The absolute position.

buffer	back to summary
private @Nullable byte[] buffer Buffer used to improve performance.

bufferPosition	back to summary
private int bufferPosition Position within buffer.

DEFAULT_MAX_BUFFER_SIZE	back to summary
pack-priv static final int DEFAULT_MAX_BUFFER_SIZE

INITIAL_BUFFER_SIZE	back to summary
pack-priv static final int INITIAL_BUFFER_SIZE

lastBufferSize	back to summary
private int lastBufferSize The amount of bytes to read on the next read. Currently, we nullify `buffer`, so we can't use `buffer.length`.

limit	back to summary
private final long limit The limit.

lo	back to summary
private @Nullable LargeObject lo The parent LargeObject.

lock	back to summary
private final ResourceLock lock

markPosition	back to summary
private long markPosition The mark position.

maxBufferSize	back to summary
private final int maxBufferSize The buffer size.

Constructor Detail

BlobInputStream	back to summary
public BlobInputStream(LargeObject lo) Parameters lo:LargeObject LargeObject to read from

BlobInputStream	back to summary
public BlobInputStream(LargeObject lo, int bsize) Parameters lo:LargeObject LargeObject to read from bsize:int buffer size

BlobInputStream	back to summary
public BlobInputStream(LargeObject lo, int bsize, long limit) Parameters lo:LargeObject LargeObject to read from bsize:int buffer size limit:long max number of bytes to read

Method Detail

close back to summary

close	back to summary
public void close() throws IOException Overrides java.io.InputStream.close. Implements java.io.Closeable.close. Closes this input stream and releases any system resources associated with the stream. The `close` method of `InputStream` does nothing. Annotations @Override Exceptions IOException: if an I/O error occurs.

public void close() throws IOException

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

Closes this input stream and releases any system resources associated with the stream.

The close method of InputStream does nothing.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

getLo	back to summary
private LargeObject getLo() throws IOException

getNextBufferSize back to summary

getNextBufferSize	back to summary
private int getNextBufferSize(int len) Computes the next buffer size to use for reading data from the large object. The idea is to avoid allocating too much memory, especially if the user will use just a few bytes of the data. Parameters len:int estimated read request Returns:int next buffer size or `maxBufferSize` if the buffer should not be increased

private int getNextBufferSize(int len)

Computes the next buffer size to use for reading data from the large object. The idea is to avoid allocating too much memory, especially if the user will use just a few bytes of the data.

Parameters

len:int: estimated read request

Returns:int

next buffer size or maxBufferSize if the buffer should not be increased

mark back to summary

mark	back to summary
public void mark(int readlimit) Overrides java.io.InputStream.mark. Marks the current position in this input stream. A subsequent call to the `reset` method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. The `readlimit` arguments tells this input stream to allow that many bytes to be read before the mark position gets invalidated. The general contract of `mark` is that, if the method `markSupported` returns `true`, the stream somehow remembers all the bytes read after the call to `mark` and stands ready to supply those same bytes again if and whenever the method `reset` is called. However, the stream is not required to remember any data at all if more than `readlimit` bytes are read from the stream before `reset` is called. Marking a closed stream should not have any effect on the stream. Parameters readlimit:int the maximum limit of bytes that can be read before the mark position becomes invalid. Annotations @Override See Also `java.io.InputStream#reset()`

public void mark(int readlimit)

Overrides java.io.InputStream.mark.

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

The readlimit arguments tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

The general contract of mark is that, if the method markSupported returns true, the stream somehow remembers all the bytes read after the call to mark and stands ready to supply those same bytes again if and whenever the method reset is called. However, the stream is not required to remember any data at all if more than readlimit bytes are read from the stream before reset is called.

Marking a closed stream should not have any effect on the stream.

Parameters

readlimit:int: the maximum limit of bytes that can be read before the mark position becomes invalid.

Annotations

@Override

See Also

java.io.InputStream#reset()

markSupported back to summary

markSupported	back to summary
public boolean markSupported() Overrides java.io.InputStream.markSupported. Tests if this input stream supports the `mark` and `reset` methods. The `markSupported` method of `InputStream` returns `false`. Returns:boolean `true` if this true type supports the mark and reset method; `false` otherwise. Annotations @Override See Also `java.io.InputStream#mark(int)`, `java.io.InputStream#reset()`

public boolean markSupported()

Overrides java.io.InputStream.markSupported.

Tests if this input stream supports the mark and reset methods. The markSupported method of InputStream returns false.

Returns:boolean

true if this true type supports the mark and reset method; false otherwise.

Annotations

@Override

read back to summary

read	back to summary
public int read() throws IOException Implements abstract java.io.InputStream.read. The minimum required to implement input stream. Returns:int Doc from java.io.InputStream.read. the next byte of data, or `-1` if the end of the stream is reached. Annotations @Override Exceptions IOException: Doc from java.io.InputStream.read. if an I/O error occurs.

public int read() throws IOException

Implements abstract java.io.InputStream.read.

The minimum required to implement input stream.

Returns:int

Doc from java.io.InputStream.read.

the next byte of data, or -1 if the end of the stream is reached.

Annotations

@Override

Exceptions

IOException:

Doc from java.io.InputStream.read.

if an I/O error occurs.

read back to summary

read	back to summary
public int read(byte[] dest, int off, int len) throws IOException Overrides java.io.InputStream.read. Doc from java.io.InputStream.read. Reads up to `len` bytes of data from the input stream into an array of bytes. An attempt is made to read as many as `len` bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown. If `len` is zero, then no bytes are read and `0` is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value `-1` is returned; otherwise, at least one byte is read and stored into `b`. The first byte read is stored into element `b[off]`, the next one into `b[off+1]`, and so on. The number of bytes read is, at most, equal to `len`. Let k be the number of bytes actually read; these bytes will be stored in elements `b[off]` through `b[off+`k`-1]`, leaving elements `b[off+`k`]` through `b[off+len-1]` unaffected. In every case, elements `b[0]` through `b[off-1]` and elements `b[off+len]` through `b[b.length-1]` are unaffected. Parameters dest:byte[] the buffer into which the data is read. off:int the start offset in array `b` at which the data is written. len:int the maximum number of bytes to read. Returns:int the total number of bytes read into the buffer, or `-1` if there is no more data because the end of the stream has been reached. Annotations @Override Exceptions IOException: If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.

public int read(byte[] dest, int off, int len) throws IOException

Overrides java.io.InputStream.read.

Doc from java.io.InputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off-1] and elements b[off+len] through b[b.length-1] are unaffected.

Parameters

dest:byte[]: the buffer into which the data is read.
off:int: the start offset in array b at which the data is written.
len:int: the maximum number of bytes to read.

Returns:int

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Annotations

@Override

Exceptions

IOException:: If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.

reset back to summary

reset	back to summary
public void reset() throws IOException Overrides java.io.InputStream.reset. Repositions this stream to the position at the time the `mark` method was last called on this input stream. Note If mark is not called we move to the beginning. Annotations @Override Exceptions IOException: Doc from java.io.InputStream.reset. if this stream has not been marked or if the mark has been invalidated. See Also `java.io.InputStream#mark(int)`, `java.io.IOException`

public void reset() throws IOException

Overrides java.io.InputStream.reset.

Repositions this stream to the position at the time the mark method was last called on this input stream.