PostgreSQL JDBC Driver 42.7.2 · org.postgresql.core.VisibleBufferedInputStream

Modifier and Type	Field and Description
private byte[]	buffer The buffer.
private int	endIndex How far is the buffer filled with valid data.
private int	index Current read position in the buffer.
private static final int	MINIMUM_READ If a direct read to byte array is called that would require a smaller read from the wrapped stream that MINIMUM_READ then first fill the buffer and serve the bytes from there.
private static final int	STRING_SCAN_SPAN In how large spans is the C string zero-byte scanned.
private boolean	timeoutRequested socket timeout has been requested
private final InputStream	wrapped The wrapped input stream.

Access	Constructor and Description
public	VisibleBufferedInputStream(InputStream The stream to buffer. in, int The initial size of the buffer. bufferSize) Creates a new buffer around the given stream.

Method Summary

Modifier and Type	Method and Description
public int	available() Overrides java.io.InputStream.available. Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected.
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 void	compact() Compacts the unread bytes of the buffer to the beginning of the buffer.
private void	doubleBuffer() Doubles the size of the buffer.
public boolean	Returns: true if required bytes are available and false if EOF ensureBytes(int The amount of bytes to ensure exists in buffer n) Ensures that the buffer contains at least n bytes.
public boolean	Returns: true if required bytes are available and false if EOF or the parameter block was false and socket timeout occurred. ensureBytes(int The amount of bytes to ensure exists in buffer n, boolean whether or not to block the IO block) Ensures that the buffer contains at least n bytes.
public byte[]	Returns: The underlaying buffer. getBuffer() Returns direct handle to the used buffer.
public int	Returns: the current read position in the buffer. getIndex() Returns the current read position in the buffer.
public InputStream	Returns: the wrapped stream getWrapped()
private void	moveBufferTo(byte[] The destination buffer. dest) Moves bytes from the buffer to the beginning of the destination buffer.
public int	Returns: byte from the buffer without advancing the index pointer peek() Reads a byte from the buffer without advancing the index pointer.
public int	read() Implements abstract java.io.InputStream.read. Reads the next byte of data from the input stream.
public int	read(byte[] the buffer into which the data is read. to, 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.
private boolean	Returns: True if at least some bytes were read. readMore(int How much should be at least read. wanted, boolean block) Reads more bytes into the buffer.
public byte	Returns: The next byte from the buffer. readRaw() Reads byte from the buffer without any checks.
public int	Returns: The length of the next null terminated string. scanCStringLength() Scans the length of the next null terminated string (C-style string) from the stream.
public void	setTimeoutRequested(boolean timeoutRequested)
public long	skip(long the number of bytes to be skipped. n) Overrides java.io.InputStream.skip. Skips over and discards `n` bytes of data from this input stream.

Inherited from java.io.InputStream:: mark markSupported nullInputStream read readAllBytes readNBytes readNBytes reset skipNBytes transferTo

buffer	back to summary
private byte[] buffer The buffer.

endIndex	back to summary
private int endIndex How far is the buffer filled with valid data.

index	back to summary
private int index Current read position in the buffer.

MINIMUM_READ	back to summary
private static final int MINIMUM_READ If a direct read to byte array is called that would require a smaller read from the wrapped stream that MINIMUM_READ then first fill the buffer and serve the bytes from there. Larger reads are directly done to the provided byte array.

STRING_SCAN_SPAN	back to summary
private static final int STRING_SCAN_SPAN In how large spans is the C string zero-byte scanned.

timeoutRequested	back to summary
private boolean timeoutRequested socket timeout has been requested

wrapped	back to summary
private final InputStream wrapped The wrapped input stream.

VisibleBufferedInputStream	back to summary
public VisibleBufferedInputStream(InputStream in, int bufferSize) Creates a new buffer around the given stream. Parameters in:InputStream The stream to buffer. bufferSize:int The initial size of the buffer.

Method Detail

available back to summary

available	back to summary
public int available() throws IOException Overrides java.io.InputStream.available. Doc from java.io.InputStream.available. Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes. Note that while some implementations of `InputStream` will return the total number of bytes in the stream, many will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream. A subclass's implementation of this method may choose to throw an `IOException` if this input stream has been closed by invoking the `close()` method. Returns:int an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking or `0` when it reaches the end of the input stream. Annotations @Override Exceptions IOException: if an I/O error occurs.

public int available() throws IOException

Overrides java.io.InputStream.available.

Doc from java.io.InputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Note that while some implementations of InputStream will return the total number of bytes in the stream, many will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream.

A subclass's implementation of this method may choose to throw an IOException if this input stream has been closed by invoking the close() method.

Returns:int

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking or 0 when it reaches the end of the input stream.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

close	back to summary
public void close() throws IOException Overrides java.io.InputStream.close. Implements java.io.Closeable.close. Doc from java.io.InputStream.close. Closes this input stream and releases any system resources associated with the stream. Annotations @Override Exceptions IOException: if an I/O error occurs.

back to summary

public void close() throws IOException

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

Doc from java.io.InputStream.close.

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

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

compact	back to summary
private void compact() Compacts the unread bytes of the buffer to the beginning of the buffer.

doubleBuffer	back to summary
private void doubleBuffer() Doubles the size of the buffer.

ensureBytes	back to summary
public boolean ensureBytes(int n) throws IOException Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields. Parameters n:int The amount of bytes to ensure exists in buffer Returns:boolean true if required bytes are available and false if EOF Exceptions IOException: If reading of the wrapped stream failed.

ensureBytes

back to summary

public boolean ensureBytes(int n) throws IOException

Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields.

Parameters

n:int: The amount of bytes to ensure exists in buffer

Returns:boolean

true if required bytes are available and false if EOF

Exceptions

IOException:: If reading of the wrapped stream failed.

ensureBytes	back to summary
public boolean ensureBytes(int n, boolean block) throws IOException Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields. Parameters n:int The amount of bytes to ensure exists in buffer block:boolean whether or not to block the IO Returns:boolean true if required bytes are available and false if EOF or the parameter block was false and socket timeout occurred. Exceptions IOException: If reading of the wrapped stream failed.

ensureBytes

back to summary

public boolean ensureBytes(int n, boolean block) throws IOException

Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields.

Parameters

n:int: The amount of bytes to ensure exists in buffer
block:boolean: whether or not to block the IO

Returns:boolean

true if required bytes are available and false if EOF or the parameter block was false and socket timeout occurred.

Exceptions

IOException:: If reading of the wrapped stream failed.

getBuffer back to summary

getBuffer	back to summary
public byte[] getBuffer() Returns direct handle to the used buffer. Use the `ensureBytes` to prefill required bytes the buffer and `getIndex` to fetch the current position of the buffer. Returns:byte[] The underlaying buffer.

public byte[] getBuffer()

Returns direct handle to the used buffer. Use the ensureBytes to prefill required bytes the buffer and getIndex to fetch the current position of the buffer.

Returns:byte[]: The underlaying buffer.

getIndex	back to summary
public int getIndex() Returns the current read position in the buffer. Returns:int the current read position in the buffer.

getIndex

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public int getIndex()

Returns the current read position in the buffer.

Returns:int: the current read position in the buffer.

getWrapped	back to summary
public InputStream getWrapped() Returns:InputStream the wrapped stream

moveBufferTo	back to summary
private void moveBufferTo(byte[] dest) Moves bytes from the buffer to the beginning of the destination buffer. Also sets the index and endIndex variables. Parameters dest:byte[] The destination buffer.

moveBufferTo

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private void moveBufferTo(byte[] dest)

Moves bytes from the buffer to the beginning of the destination buffer. Also sets the index and endIndex variables.

Parameters

dest:byte[]: The destination buffer.

peek	back to summary
public int peek() throws IOException Reads a byte from the buffer without advancing the index pointer. Returns:int byte from the buffer without advancing the index pointer Exceptions IOException: if something wrong happens

peek

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public int peek() throws IOException

Reads a byte from the buffer without advancing the index pointer.

Returns:int

byte from the buffer without advancing the index pointer

Exceptions

IOException:: if something wrong happens

read back to summary

read	back to summary
public int read() throws IOException Implements abstract java.io.InputStream.read. Doc from java.io.InputStream.read. Reads the next byte of data from the input stream. The value byte is returned as an `int` in the range `0` to `255`. If no byte is available because the end of the stream has been reached, the value `-1` is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown. Returns:int the next byte of data, or `-1` if the end of the stream is reached. Annotations @Override Exceptions IOException: if an I/O error occurs.

public int read() throws IOException

Implements abstract java.io.InputStream.read.

Doc from java.io.InputStream.read.

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Returns:int

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

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

read back to summary

read	back to summary
public int read(byte[] to, 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 to: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[] to, 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

to: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.

readMore	back to summary
private boolean readMore(int wanted, boolean block) throws IOException Reads more bytes into the buffer. Parameters wanted:int How much should be at least read. Returns:boolean True if at least some bytes were read. Exceptions IOException: If reading of the wrapped stream failed.

back to summary

private boolean readMore(int wanted, boolean block) throws IOException

Reads more bytes into the buffer.

Parameters

wanted:int: How much should be at least read.

Returns:boolean

True if at least some bytes were read.

Exceptions

IOException:: If reading of the wrapped stream failed.

readRaw back to summary

readRaw	back to summary
public byte readRaw() Reads byte from the buffer without any checks. This method never reads from the underlaying stream. Before calling this method the `ensureBytes` method must have been called. Returns:byte The next byte from the buffer. Exceptions ArrayIndexOutOfBoundsException: If ensureBytes was not called to make sure the buffer contains the byte.

public byte readRaw()

Reads byte from the buffer without any checks. This method never reads from the underlaying stream. Before calling this method the ensureBytes method must have been called.

Returns:byte

The next byte from the buffer.

Exceptions

ArrayIndexOutOfBoundsException:: If ensureBytes was not called to make sure the buffer contains the byte.

scanCStringLength	back to summary
public int scanCStringLength() throws IOException Scans the length of the next null terminated string (C-style string) from the stream. Returns:int The length of the next null terminated string. Exceptions IOException: If reading of stream fails. EOFException: If the stream did not contain any null terminators.

scanCStringLength

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public int scanCStringLength() throws IOException

Scans the length of the next null terminated string (C-style string) from the stream.

Returns:int

The length of the next null terminated string.

Exceptions

IOException:: If reading of stream fails.
EOFException:: If the stream did not contain any null terminators.

setTimeoutRequested	back to summary
public void setTimeoutRequested(boolean timeoutRequested)

skip back to summary

skip	back to summary
public long skip(long n) throws IOException Overrides java.io.InputStream.skip. Doc from java.io.InputStream.skip. Skips over and discards `n` bytes of data from this input stream. The `skip` method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly `0`. This may result from any of a number of conditions; reaching end of file before `n` bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If `n` is negative, the `skip` method for class `InputStream` always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently. Parameters n:long the number of bytes to be skipped. Returns:long the actual number of bytes skipped which might be zero. Annotations @Override Exceptions IOException: if an I/O error occurs.

public long skip(long n) throws IOException

Overrides java.io.InputStream.skip.

Doc from java.io.InputStream.skip.

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, the skip method for class InputStream always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently.

Parameters

n:long: the number of bytes to be skipped.

Returns:long

the actual number of bytes skipped which might be zero.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

public Class VisibleBufferedInputStream

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Field Detail

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