Top Description Fields Constructors Methods
com.mysql.cj.protocol

public Class ReadAheadInputStream

extends InputStream
Class Inheritance
Imports
java.io.IOException, .InputStream, java.util.Arrays, java.util.concurrent.locks.Lock, .ReentrantLock, com.mysql.cj.log.Log
A non-blocking buffered input stream. Reads more if it can, won't block to fill the buffer, only blocks to satisfy a request of read(byte[])

Field Summary

Modifier and TypeField and Description
private byte[]
buf

protected int
currentPosition

private static final int
DEFAULT_BUFFER_SIZE

Hides java.io.InputStream.DEFAULT_BUFFER_SIZE.

protected boolean
doDebug

protected int
endOfCurrentData

private final Lock
lock

protected Log
log

private InputStream
underlyingStream

Constructor Summary

AccessConstructor and Description
public
ReadAheadInputStream(InputStream toBuffer, boolean debug, Log logTo)

public
ReadAheadInputStream(InputStream toBuffer, int bufferSize, boolean debug, Log logTo)

Method Summary

Modifier and TypeMethod 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.

private void
checkClosed()

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
fill(int readAtLeastTheseManyBytes)

public boolean
markSupported()

Overrides java.io.InputStream.markSupported.

Tests if this input stream supports the mark and reset methods.

public int
read(byte[]
the buffer into which the data is read.
b, 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 int
read()

Implements abstract java.io.InputStream.read.

Reads the next byte of data from the input stream.

private int
readFromUnderlyingStreamIfNecessary(byte[] b, int off, int len)

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:
marknullInputStreamreadreadAllBytesreadNBytesreadNBytesresetskipNBytestransferTo

Field Detail

bufback to summary
private byte[] buf
currentPositionback to summary
protected int currentPosition
DEFAULT_BUFFER_SIZEback to summary
private static final int DEFAULT_BUFFER_SIZE

Hides java.io.InputStream.DEFAULT_BUFFER_SIZE.

doDebugback to summary
protected boolean doDebug
endOfCurrentDataback to summary
protected int endOfCurrentData
lockback to summary
private final Lock lock
logback to summary
protected Log log
underlyingStreamback to summary
private InputStream underlyingStream

Constructor Detail

ReadAheadInputStreamback to summary
public ReadAheadInputStream(InputStream toBuffer, boolean debug, Log logTo)
ReadAheadInputStreamback to summary
public ReadAheadInputStream(InputStream toBuffer, int bufferSize, boolean debug, Log logTo)

Method Detail

availableback 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.
checkClosedback to summary
private void checkClosed() throws IOException
closeback 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.
fillback to summary
private void fill(int readAtLeastTheseManyBytes) throws IOException
markSupportedback to summary
public boolean markSupported()

Overrides java.io.InputStream.markSupported.

Doc from java.io.InputStream.markSupported.

Tests if this input stream supports the mark and reset methods. Whether or not mark and reset are supported is an invariant property of a particular input stream instance.

Returns:boolean

true if this stream instance supports the mark and reset methods; false otherwise.

Annotations
@Override
readback to summary
public int read(byte[] b, 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
b: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.
readback 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.
readFromUnderlyingStreamIfNecessaryback to summary
private int readFromUnderlyingStreamIfNecessary(byte[] b, int off, int len) throws IOException
skipback 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.