Apache Derby Client JDBC Driver 10.17.1.0 · org.apache.derby.client.am.Lob

Field Summary

Modifier and Type	Field and Description
protected Agent	agent_
pack-priv static final int	ASCII_STREAM
pack-priv static final int	BINARY_STREAM
pack-priv static final int	BINARY_STRING
pack-priv static final int	CHARACTER_STREAM
protected int	dataType_
public static final int	INVALID_LOCATOR
protected boolean	isValid_ This boolean variable indicates whether the Lob object has been invalidated by calling free() on it
private boolean	lengthObtained_
private static final ClientMessageId	LOB_OBJECT_LENGTH_UNKNOWN_YET
pack-priv static final int	LOCATOR
protected int	locator_
private long	sqlLength_
pack-priv static final int	STRING
private int	transactionID_ This integer identifies which transaction the Lob is associated with
pack-priv static final int	UNICODE_STREAM
private long	updateCount
private final boolean	willBeLayerBStreamed_

Constructor Summary

Access	Constructor and Description
protected	Lob(Agent agent, boolean willBeLayerBStreamed)

Method Summary

Modifier and Type	Method and Description
pack-priv void	checkForClosedConnection()
pack-priv void	checkForLocatorValidity() Calls SqlLength() to check if the Locator associated with the underlying Lob is valid.
protected void	checkPosAndLength(long a long that contains the position that needs to be checked pos, long a long that contains the length that needs to be checked length) Checks the `pos` and `length`.
protected void	checkValidity() Checks if isValid is true and whether the transaction that created the Lob is still active.
public void	completeLocalCommit(Iterator<E> listenerIterator) Implements org.apache.derby.client.am.UnitOfWorkListener.completeLocalCommit.
public void	completeLocalRollback(Iterator<E> listenerIterator) Implements org.apache.derby.client.am.UnitOfWorkListener.completeLocalRollback.
public Agent	getAgent()
public int	Returns: locator for this Lob, INVALID_LOCATOR if Lob is not based on locator getLocator() Get locator for this Lob
pack-priv long	Returns: length of Lob getLocatorLength() Get the length of locator based Lob from the server.
pack-priv long	getUpdateCount() Returns the current updateCount of the Clob.
protected synchronized void	incrementUpdateCount() Increments and returns the new updateCount of this `Lob`.
protected static boolean	isLayerBStreamingPossible(Agent agent)
public boolean	Returns: true if Lob is based on locator, false otherwise isLocator() Check whether this Lob is based on a locator
public abstract long	length()
public void	listenToUnitOfWork() Implements org.apache.derby.client.am.UnitOfWorkListener.listenToUnitOfWork.
protected abstract void	materializeStream() Method to be implemented by subclasses, so that #materializedStream(InputStream, String) can be called with subclass specific parameters and the result assigned to the right stream.
protected InputStream	Returns: a stream whose source is the materialized data materializeStream(InputStream stream to use for input is, String description of the data type we are inserting, for instance `java.sql.Clob` typeDesc) Materialize the given stream into memory and update the internal length variable.
pack-priv void	setSqlLength(long the new length of the Lob value length) Update the registered length of the Lob value.
pack-priv long	Returns: length of Lob value sqlLength() Return the length of the Lob value represented by this Lob object.
public boolean	willBeLayerBStreamed()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

agent_	back to summary
protected Agent agent_

ASCII_STREAM	back to summary
pack-priv static final int ASCII_STREAM

BINARY_STREAM	back to summary
pack-priv static final int BINARY_STREAM

BINARY_STRING	back to summary
pack-priv static final int BINARY_STRING

CHARACTER_STREAM	back to summary
pack-priv static final int CHARACTER_STREAM

dataType_	back to summary
protected int dataType_

INVALID_LOCATOR	back to summary
public static final int INVALID_LOCATOR

isValid_	back to summary
protected boolean isValid_ This boolean variable indicates whether the Lob object has been invalidated by calling free() on it

lengthObtained_	back to summary
private boolean lengthObtained_

LOB_OBJECT_LENGTH_UNKNOWN_YET	back to summary
private static final ClientMessageId LOB_OBJECT_LENGTH_UNKNOWN_YET

LOCATOR	back to summary
pack-priv static final int LOCATOR

locator_	back to summary
protected int locator_

sqlLength_	back to summary
private long sqlLength_

STRING	back to summary
pack-priv static final int STRING

transactionID_	back to summary
private int transactionID_ This integer identifies which transaction the Lob is associated with

UNICODE_STREAM	back to summary
pack-priv static final int UNICODE_STREAM

updateCount	back to summary
private long updateCount

willBeLayerBStreamed_	back to summary
private final boolean willBeLayerBStreamed_

Constructor Detail

Lob	back to summary
protected Lob(Agent agent, boolean willBeLayerBStreamed)

Method Detail

checkForClosedConnection	back to summary
pack-priv void checkForClosedConnection() throws SqlException

checkForLocatorValidity	back to summary
pack-priv void checkForLocatorValidity() throws SqlException Calls SqlLength() to check if the Locator associated with the underlying Lob is valid. If it is not it throws an exception.

checkPosAndLength back to summary

checkPosAndLength	back to summary
protected void checkPosAndLength(long pos, long length) throws SQLException Checks the `pos` and `length`. Parameters pos:long a long that contains the position that needs to be checked length:long a long that contains the length that needs to be checked Exceptions SQLException: if a) pos <= 0 b) pos > (length of LOB) c) length < 0 d) (pos -1) + length > (length of LOB)

protected void checkPosAndLength(long pos, long length) throws SQLException

Checks the pos and length.

Parameters

pos:long: a long that contains the position that needs to be checked
length:long: a long that contains the length that needs to be checked

Exceptions

SQLException:: if a) pos <= 0 b) pos > (length of LOB) c) length < 0 d) (pos -1) + length > (length of LOB)

checkValidity	back to summary
protected void checkValidity() throws SQLException Checks if isValid is true and whether the transaction that created the Lob is still active. If any of which is not true throws a SQLException stating that a method has been called on an invalid LOB object. Exceptions SQLException: if isValid is not true or the transaction that created the Lob is not active

checkValidity

back to summary

protected void checkValidity() throws SQLException

Checks if isValid is true and whether the transaction that created the Lob is still active. If any of which is not true throws a SQLException stating that a method has been called on an invalid LOB object.

Exceptions

SQLException:: if isValid is not true or the transaction that created the Lob is not active

completeLocalCommit	back to summary
public void completeLocalCommit(Iterator<E> listenerIterator) Implements org.apache.derby.client.am.UnitOfWorkListener.completeLocalCommit.

completeLocalRollback	back to summary
public void completeLocalRollback(Iterator<E> listenerIterator) Implements org.apache.derby.client.am.UnitOfWorkListener.completeLocalRollback.

getAgent	back to summary
public Agent getAgent()

getLocator	back to summary
public int getLocator() Get locator for this Lob Returns:int locator for this Lob, INVALID_LOCATOR if Lob is not based on locator

getLocator

back to summary

public int getLocator()

Get locator for this Lob

Returns:int: locator for this Lob, INVALID_LOCATOR if Lob is not based on locator

getLocatorLength	back to summary
pack-priv long getLocatorLength() throws SqlException Get the length of locator based Lob from the server. This is a dummy implementation that is supposed to be overridden by subclasses. A stored procedure call will be made to get the length from the server. Returns:long length of Lob

getLocatorLength

back to summary

pack-priv long getLocatorLength() throws SqlException

Get the length of locator based Lob from the server. This is a dummy implementation that is supposed to be overridden by subclasses. A stored procedure call will be made to get the length from the server.

Returns:long: length of Lob

getUpdateCount	back to summary
pack-priv long getUpdateCount() Returns the current updateCount of the Clob.

incrementUpdateCount back to summary

incrementUpdateCount	back to summary
protected synchronized void incrementUpdateCount() Increments and returns the new updateCount of this `Lob`. The method needs to be synchronized since multiple updates can happen on this `Lob` simultaneously. It will be called from the 1) Locator Writers 2) Locator OutputStreams 3) From the update methods within the Lobs like setString, truncate. since all of the above acesses are inside the am package, this method will have default access. We do not need to worry about the non-locator streams since non-locator InputStreams would not depend on updateCount for invalidation

protected synchronized void incrementUpdateCount()

Increments and returns the new updateCount of this Lob. The method needs to be synchronized since multiple updates can happen on this Lob simultaneously. It will be called from the 1) Locator Writers 2) Locator OutputStreams 3) From the update methods within the Lobs like setString, truncate. since all of the above acesses are inside the am package, this method will have default access. We do not need to worry about the non-locator streams since non-locator InputStreams would not depend on updateCount for invalidation

isLayerBStreamingPossible	back to summary
protected static boolean isLayerBStreamingPossible(Agent agent)

isLocator	back to summary
public boolean isLocator() Check whether this Lob is based on a locator Returns:boolean true if Lob is based on locator, false otherwise

isLocator

back to summary

public boolean isLocator()

Check whether this Lob is based on a locator

Returns:boolean: true if Lob is based on locator, false otherwise

length	back to summary
public abstract long length() throws SQLException

listenToUnitOfWork	back to summary
public void listenToUnitOfWork() Implements org.apache.derby.client.am.UnitOfWorkListener.listenToUnitOfWork.

materializeStream	back to summary
protected abstract void materializeStream() throws SqlException Method to be implemented by subclasses, so that #materializedStream(InputStream, String) can be called with subclass specific parameters and the result assigned to the right stream. Exceptions SqlException: on error

materializeStream

back to summary

protected abstract void materializeStream() throws SqlException

Method to be implemented by subclasses, so that #materializedStream(InputStream, String) can be called with subclass specific parameters and the result assigned to the right stream.

Exceptions

SqlException:: on error

materializeStream back to summary

materializeStream	back to summary
protected InputStream materializeStream(InputStream is, String typeDesc) throws SqlException Materialize the given stream into memory and update the internal length variable. Parameters is:InputStream stream to use for input typeDesc:String description of the data type we are inserting, for instance `java.sql.Clob` Returns:InputStream a stream whose source is the materialized data Exceptions SqlException: if the stream exceeds 2 GB, or an error happens while reading from the stream

protected InputStream materializeStream(InputStream is, String typeDesc) throws SqlException

Materialize the given stream into memory and update the internal length variable.

Parameters

is:InputStream: stream to use for input
typeDesc:String: description of the data type we are inserting, for instance java.sql.Clob

Returns:InputStream

a stream whose source is the materialized data

Exceptions

SqlException:: if the stream exceeds 2 GB, or an error happens while reading from the stream

setSqlLength	back to summary
pack-priv void setSqlLength(long length) Update the registered length of the Lob value. To be called by methods that make changes to the length of the Lob. Note The caller needs to deal with synchronization. Parameters length:long the new length of the Lob value

setSqlLength

back to summary

pack-priv void setSqlLength(long length)

Update the registered length of the Lob value. To be called by methods that make changes to the length of the Lob.

Note

The caller needs to deal with synchronization.

Parameters

length:long: the new length of the Lob value

sqlLength	back to summary
pack-priv long sqlLength() throws SqlException Return the length of the Lob value represented by this Lob object. If length is not already known, and Lob is locator based, length will be retrieved from the server. If not, locator based, Lob will first be materialized. Note The caller needs to deal with synchronization. Returns:long length of Lob value Exceptions SqlException: on execution errors while materializing the stream, or if Layer B streaming is used and length not yet obtained.

sqlLength

back to summary

pack-priv long sqlLength() throws SqlException

Return the length of the Lob value represented by this Lob object. If length is not already known, and Lob is locator based, length will be retrieved from the server. If not, locator based, Lob will first be materialized.

Note

The caller needs to deal with synchronization.

Returns:long

length of Lob value

Exceptions

SqlException:: on execution errors while materializing the stream, or if Layer B streaming is used and length not yet obtained.

willBeLayerBStreamed	back to summary
public boolean willBeLayerBStreamed()

public abstract Class Lob

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