Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.iapi.types.ReaderToUTF8Stream

Field Summary

Modifier and Type	Field and Description
private int	blen
private int	boff
private byte[]	buffer Buffer to hold the data read from stream and converted to the modified UTF-8 format.
private int	charCount The number of chars encoded.
private final int	charsToTruncate Number of characters to truncate from this stream.
private boolean	eof
private static final int	FIRST_READ Constant indicating the first iteration of `fillBuffer`.
private final StreamHeaderGenerator	hdrGen The generator for the stream header to use for this stream.
private int	headerLength The length of the header.
private int	mark Stream mark, set through mark(int).
private static final int	MARK_UNSET_OR_EXCEEDED Constant indicating that no mark is set in the stream, or that the read ahead limit of the mark has been exceeded.
private boolean	multipleBuffer Tells if the stream content is/was larger than the buffer size.
private static final int	READ_BUFFER_RESERVATION Buffer space reserved for one 3 byte encoded char and the EOF marker.
private int	readAheadLimit Read ahead limit for mark, set through mark(int).
private LimitReader	reader Application's reader wrapped in a LimitReader.
private static final char	SPACE
private final String	typeName The type name for the column data is inserted into.
private final int	valueLength If positive, length of the expected final value, after truncation if any, in characters.

Constructor Summary

Access	Constructor and Description
public	ReaderToUTF8Stream(Reader application reader appReader, int the expected length of the reader in characters (positive), or the inverse (maxColWidth * -1) of the maximum column width if the expected stream length is unknown valueLength, int the number of trailing blanks to truncate numCharsToTruncate, String type name of the column data is inserted into typeName, StreamHeaderGenerator the stream header generator headerGenerator) Create a stream that will truncate trailing blanks if required/allowed.
public	ReaderToUTF8Stream(Reader application reader appReader, int maximum allowed length in number of characters for the reader, typically the maximum field size maximumLength, String type name of the column data is inserted into typeName, StreamHeaderGenerator the stream header generator headerGenerator) Creates a UTF-8 stream for an application reader whose length isn't known at insertion time.

Access

Constructor and Description

public

ReaderToUTF8Stream(Reader

application reader

appReader, int

the expected length of the reader in characters (positive), or the inverse (maxColWidth * -1) of the maximum column width if the expected stream length is unknown

valueLength, int

the number of trailing blanks to truncate

numCharsToTruncate, String

type name of the column data is inserted into

typeName, StreamHeaderGenerator

the stream header generator

headerGenerator)

Create a stream that will truncate trailing blanks if required/allowed.

public

ReaderToUTF8Stream(Reader

application reader

appReader, int

maximum allowed length in number of characters for the reader, typically the maximum field size

maximumLength, String

type name of the column data is inserted into

typeName, StreamHeaderGenerator

the stream header generator

headerGenerator)

Creates a UTF-8 stream for an application reader whose length isn't known at insertion time.

Method Summary

Modifier and Type	Method and Description
public final int	available() Overrides java.io.InputStream.available. Return an optimized version of bytes available to read from the stream.
private boolean	canTruncate() Determine if trailing blank truncation is allowed.
private void	checkSufficientData() Validate the length of the stream, take corrective action if allowed.
public void	close() Overrides java.io.InputStream.close. Implements java.io.Closeable.close. return resources
private void	fillBuffer(int offset at which to start filling the buffer, used to avoid overwriting the stream header data on the first iteration startingOffset) Fills the internal buffer with data read from the source stream.
public void	mark(int the maximum limit of bytes that can be read before the mark position becomes invalid readAheadLimit) Overrides java.io.InputStream.mark. Marks the current position in the stream.
public boolean	Returns: `true`, mark/reset is always supported. markSupported() Overrides java.io.InputStream.markSupported. Tests if this stream supports mark/reset.
public int	Returns: The byte read, or `-1` if the end-of-stream is reached. read() Implements abstract java.io.InputStream.read. Reads a byte from the stream.
public int	Returns: The number of bytes read, or `-1` if the end-of-stream is reached. 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 from the stream.
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.
private void	truncate() Attempt to truncate the stream by removing trailing blanks.

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

Field Detail

blen	back to summary
private int blen

boff	back to summary
private int boff

buffer	back to summary
private byte[] buffer Buffer to hold the data read from stream and converted to the modified UTF-8 format. The initial size is dependent on whether the data value length is known (limited upwards to 32 KB), but it may grow if mark(int) is invoked.

charCount	back to summary
private int charCount The number of chars encoded.

charsToTruncate	back to summary
private final int charsToTruncate Number of characters to truncate from this stream. The SQL standard allows for truncation of trailing spaces for CLOB, VARCHAR and CHAR. If zero, no characters are truncated, unless the stream length exceeds the maximum length of the column we are inserting into.

eof	back to summary
private boolean eof

FIRST_READ	back to summary
private static final int FIRST_READ Constant indicating the first iteration of `fillBuffer`.

hdrGen back to summary

hdrGen	back to summary
private final StreamHeaderGenerator hdrGen The generator for the stream header to use for this stream. See Also `checkSufficientData()`

private final StreamHeaderGenerator hdrGen

The generator for the stream header to use for this stream.

See Also: checkSufficientData()

headerLength	back to summary
private int headerLength The length of the header.

mark	back to summary
private int mark Stream mark, set through mark(int).

MARK_UNSET_OR_EXCEEDED	back to summary
private static final int MARK_UNSET_OR_EXCEEDED Constant indicating that no mark is set in the stream, or that the read ahead limit of the mark has been exceeded.

multipleBuffer	back to summary
private boolean multipleBuffer Tells if the stream content is/was larger than the buffer size.

READ_BUFFER_RESERVATION	back to summary
private static final int READ_BUFFER_RESERVATION Buffer space reserved for one 3 byte encoded char and the EOF marker.

readAheadLimit	back to summary
private int readAheadLimit Read ahead limit for mark, set through mark(int).

reader	back to summary
private LimitReader reader Application's reader wrapped in a LimitReader.

SPACE	back to summary
private static final char SPACE

typeName	back to summary
private final String typeName The type name for the column data is inserted into.

valueLength	back to summary
private final int valueLength If positive, length of the expected final value, after truncation if any, in characters. If negative, the maximum length allowed in the column we are inserting into. A negative value means we are working with a stream of unknown length, inserted through one of the JDBC 4.0 "lengthless override" methods.

Constructor Detail

ReaderToUTF8Stream	back to summary
public ReaderToUTF8Stream(Reader appReader, int valueLength, int numCharsToTruncate, String typeName, StreamHeaderGenerator headerGenerator) Create a stream that will truncate trailing blanks if required/allowed. If the stream must be truncated, the number of blanks to truncate is specified to allow the stream to be checked for exact length, as required by JDBC 3.0. If the stream is shorter or longer than specified, an exception is thrown during read. Parameters appReader:Reader application reader valueLength:int the expected length of the reader in characters (positive), or the inverse (maxColWidth * -1) of the maximum column width if the expected stream length is unknown numCharsToTruncate:int the number of trailing blanks to truncate typeName:String type name of the column data is inserted into headerGenerator:StreamHeaderGenerator the stream header generator

ReaderToUTF8Stream

back to summary

public ReaderToUTF8Stream(Reader appReader, int valueLength, int numCharsToTruncate, String typeName, StreamHeaderGenerator headerGenerator)

Create a stream that will truncate trailing blanks if required/allowed. If the stream must be truncated, the number of blanks to truncate is specified to allow the stream to be checked for exact length, as required by JDBC 3.0. If the stream is shorter or longer than specified, an exception is thrown during read.

Parameters

appReader:Reader: application reader
valueLength:int: the expected length of the reader in characters (positive), or the inverse (maxColWidth * -1) of the maximum column width if the expected stream length is unknown
numCharsToTruncate:int: the number of trailing blanks to truncate
typeName:String: type name of the column data is inserted into
headerGenerator:StreamHeaderGenerator: the stream header generator

ReaderToUTF8Stream	back to summary
public ReaderToUTF8Stream(Reader appReader, int maximumLength, String typeName, StreamHeaderGenerator headerGenerator) Creates a UTF-8 stream for an application reader whose length isn't known at insertion time. The application reader is coming in through one of the "lengthless overrides" added in JDBC 4.0, for instance java.sql.PreparedStatement.setCharacterStream(int,Reader). A limit is placed on the length of the application reader. If the reader exceeds the maximum length, truncation of trailing blanks is attempted. If truncation fails, an exception is thrown. Parameters appReader:Reader application reader maximumLength:int maximum allowed length in number of characters for the reader, typically the maximum field size typeName:String type name of the column data is inserted into headerGenerator:StreamHeaderGenerator the stream header generator Exceptions IllegalArgumentException: if maximum length is negative

ReaderToUTF8Stream

back to summary

public ReaderToUTF8Stream(Reader appReader, int maximumLength, String typeName, StreamHeaderGenerator headerGenerator)

Creates a UTF-8 stream for an application reader whose length isn't known at insertion time.

The application reader is coming in through one of the "lengthless overrides" added in JDBC 4.0, for instance java.sql.PreparedStatement.setCharacterStream(int,Reader). A limit is placed on the length of the application reader. If the reader exceeds the maximum length, truncation of trailing blanks is attempted. If truncation fails, an exception is thrown.

Parameters

appReader:Reader: application reader
maximumLength:int: maximum allowed length in number of characters for the reader, typically the maximum field size
typeName:String: type name of the column data is inserted into
headerGenerator:StreamHeaderGenerator: the stream header generator

Exceptions

IllegalArgumentException:: if maximum length is negative

Method Detail

available back to summary

available	back to summary
public final int available() Overrides java.io.InputStream.available. Return an optimized version of bytes available to read from the stream. Note, it is not exactly per `java.io.InputStream#available()`. Returns:int Doc from java.io.InputStream.available. 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.

public final int available()

Overrides java.io.InputStream.available.

Return an optimized version of bytes available to read from the stream.

Note, it is not exactly per java.io.InputStream#available().

Returns:int

Doc from java.io.InputStream.available.

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.

canTruncate	back to summary
private boolean canTruncate() Determine if trailing blank truncation is allowed.

checkSufficientData	back to summary
private void checkSufficientData() throws IOException Validate the length of the stream, take corrective action if allowed. JDBC 3.0 (from tutorial book) requires that an input stream has the correct number of bytes in the stream. If the stream is too long, trailing blank truncation is attempted if allowed. If truncation fails, or is disallowed, an exception is thrown. Exceptions IOException: if an errors occurs in the application stream DerbyIOException: if Derby finds a problem with the stream; stream is too long and cannot be truncated, or the stream length does not match the specified length

checkSufficientData

back to summary

private void checkSufficientData() throws IOException

Validate the length of the stream, take corrective action if allowed. JDBC 3.0 (from tutorial book) requires that an input stream has the correct number of bytes in the stream. If the stream is too long, trailing blank truncation is attempted if allowed. If truncation fails, or is disallowed, an exception is thrown.

Exceptions

IOException:: if an errors occurs in the application stream
DerbyIOException:: if Derby finds a problem with the stream; stream is too long and cannot be truncated, or the stream length does not match the specified length

close	back to summary
public void close() Overrides java.io.InputStream.close. Implements java.io.Closeable.close. return resources

back to summary

public void close()

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

return resources

fillBuffer	back to summary
private void fillBuffer(int startingOffset) throws IOException Fills the internal buffer with data read from the source stream. The characters read from the source are converted to the modified UTF-8 encoding, used as the on-disk format by Derby. Parameters startingOffset:int offset at which to start filling the buffer, used to avoid overwriting the stream header data on the first iteration Exceptions IOException: if reading from the source stream fails DerbyIOException: if the source stream has an invalid length (different than specified), or if truncation of blanks fails

fillBuffer

back to summary

private void fillBuffer(int startingOffset) throws IOException

Fills the internal buffer with data read from the source stream.

The characters read from the source are converted to the modified UTF-8 encoding, used as the on-disk format by Derby.

Parameters

startingOffset:int: offset at which to start filling the buffer, used to avoid overwriting the stream header data on the first iteration

Exceptions

IOException:: if reading from the source stream fails
DerbyIOException:: if the source stream has an invalid length (different than specified), or if truncation of blanks fails

mark	back to summary
public void mark(int readAheadLimit) Overrides java.io.InputStream.mark. Marks the current position in the stream. Note that this stream is not marked at position zero by default (i.e. in the constructor). Parameters readAheadLimit:int the maximum limit of bytes that can be read before the mark position becomes invalid

mark

back to summary

public void mark(int readAheadLimit)

Overrides java.io.InputStream.mark.

Marks the current position in the stream.

Note that this stream is not marked at position zero by default (i.e. in the constructor).

Parameters

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

markSupported back to summary

markSupported	back to summary
public boolean markSupported() Overrides java.io.InputStream.markSupported. Tests if this stream supports mark/reset. The `markSupported` method of `ByteArrayInputStream` always returns `true`. Returns:boolean `true`, mark/reset is always supported.

public boolean markSupported()

Overrides java.io.InputStream.markSupported.

Tests if this stream supports mark/reset.

The markSupported method of ByteArrayInputStream always returns true.

Returns:boolean: true, mark/reset is always supported.

read back to summary

read	back to summary
public int read() throws IOException Implements abstract java.io.InputStream.read. Reads a byte from the stream. Characters read from the source stream are converted to the UTF-8 Derby specific encoding. Returns:int The byte read, or `-1` if the end-of-stream is reached. Exceptions IOException: if reading from the source stream fails EOFException: if the end-of-stream has already been reached or the stream has been closed See Also `java.io.InputStream#read()`

public int read() throws IOException

Implements abstract java.io.InputStream.read.

Reads a byte from the stream.

Characters read from the source stream are converted to the UTF-8 Derby specific encoding.

Returns:int

The byte read, or -1 if the end-of-stream is reached.

Exceptions

IOException:: if reading from the source stream fails
EOFException:: if the end-of-stream has already been reached or the stream has been closed

See Also

java.io.InputStream#read()

read back to summary

read	back to summary
public int read(byte[] b, int off, int len) throws IOException Overrides java.io.InputStream.read. Reads up to `len` bytes from the stream. Characters read from the source stream are converted to the UTF-8 Derby specific encoding. Parameters b:byte[] Doc from java.io.InputStream.read. the buffer into which the data is read. off:int Doc from java.io.InputStream.read. the start offset in array `b` at which the data is written. len:int Doc from java.io.InputStream.read. the maximum number of bytes to read. Returns:int The number of bytes read, or `-1` if the end-of-stream is reached. Exceptions IOException: if reading from the source stream fails EOFException: if the end-of-stream has already been reached or the stream has been closed See Also `java.io.InputStream#read(byte[], int, int)`

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

Overrides java.io.InputStream.read.

Reads up to len bytes from the stream.

Characters read from the source stream are converted to the UTF-8 Derby specific encoding.

Parameters

b:byte[]

Doc from java.io.InputStream.read.

the buffer into which the data is read.

off:int

Doc from java.io.InputStream.read.

the start offset in array b at which the data is written.

len:int

Doc from java.io.InputStream.read.

the maximum number of bytes to read.

Returns:int

The number of bytes read, or -1 if the end-of-stream is reached.

Exceptions

IOException:: if reading from the source stream fails
EOFException:: if the end-of-stream has already been reached or the stream has been closed

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. Exceptions IOException: if no mark has been set, or the read ahead limit of the mark has been exceeded EOFException: if the stream has been closed

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.

Exceptions

IOException:: if no mark has been set, or the read ahead limit of the mark has been exceeded
EOFException:: if the stream has been closed

truncate	back to summary
private void truncate() throws IOException Attempt to truncate the stream by removing trailing blanks.

public final Class ReaderToUTF8Stream

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail