Package org.apache.derby.client.am
Class ClientBlob
java.lang.Object
org.apache.derby.client.am.Lob
org.apache.derby.client.am.ClientBlob
- All Implemented Interfaces:
Blob
,UnitOfWorkListener
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Field Summary
FieldsModifier and TypeFieldDescription(package private) InputStream
(package private) byte[]
(package private) int
Fields inherited from class org.apache.derby.client.am.Lob
agent_, ASCII_STREAM, BINARY_STREAM, BINARY_STRING, CHARACTER_STREAM, dataType_, INVALID_LOCATOR, isValid_, LOCATOR, locator_, STRING, UNICODE_STREAM
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Constructor Summary
ConstructorsConstructorDescriptionClientBlob
(byte[] binaryString, Agent agent, int dataOffset) ClientBlob
(Agent agent, int locator) Create aBlob
object for a Blob value stored on the server and indentified bylocator
.ClientBlob
(Agent agent, InputStream binaryStream) Create a newBlob
from a stream with unknown length.ClientBlob
(Agent agent, InputStream binaryStream, int length) -
Method Summary
Modifier and TypeMethodDescriptionprivate long
binaryStringPosition
(byte[] pattern, long start) void
free()
This method frees theBlob
object and releases the resources that it holds.getBinaryStream
(long pos, long length) Returns anInputStream
object that contains a partialBlob
value, starting with the byte specified by pos, which is length bytes in length.(package private) InputStream
byte[]
getBytes
(long pos, int length) Returns as an array of bytes part or all of theBLOB
value that thisBlob
object designates.private byte[]
getBytesX
(long pos, int length) (package private) long
Get the length in bytes of theBlob
value represented by this locator basedobject. boolean
boolean
private boolean
isSubString
(byte[] pattern, int index) long
length()
protected void
Materialize the stream used for input to the database.long
position
(byte[] pattern, long start) long
private long
positionX
(byte[] pattern, long start) private long
setBinaryStream
(long pos) int
setBytes
(long pos, byte[] bytes) int
setBytes
(long pos, byte[] bytes, int offset, int len) (package private) int
setBytesX
(long pos, byte[] bytes, int offset, int len) void
truncate
(long len) Methods inherited from class org.apache.derby.client.am.Lob
checkForClosedConnection, checkForLocatorValidity, checkPosAndLength, checkValidity, completeLocalCommit, completeLocalRollback, getAgent, getLocator, getUpdateCount, incrementUpdateCount, isLayerBStreamingPossible, isLocator, listenToUnitOfWork, materializeStream, setSqlLength, sqlLength, willBeLayerBStreamed
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Field Details
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binaryString_
byte[] binaryString_ -
binaryStream_
InputStream binaryStream_ -
dataOffset_
int dataOffset_
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Constructor Details
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ClientBlob
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ClientBlob
ClientBlob(Agent agent, InputStream binaryStream, int length) -
ClientBlob
ClientBlob(Agent agent, InputStream binaryStream) Create a newBlob
from a stream with unknown length. Important: This constructor is a temporary solution for implementing lengthless overloads in the JDBC4 API. Before a proper solution can be implemented, we need to enable streaming without having to know the stream length in the DRDA protocol. See Jira DERBY-1471 and DERBY-1417 for more details. Shortcomings: This constructor will cause the whole stream to be materialized to determine its length. If the stream is big enough, the client will fail with an OutOfMemoryError. Since this is a temporary solution, state checking is not added to all methods as it would clutter up the class severely. After using the constructor, thelength
-method must be called, which will materialize the stream and determine the length. Do not pass a Blob object created with this constructor to the user!- Parameters:
agent
-binaryStream
- the stream to get data from
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ClientBlob
Create aBlob
object for a Blob value stored on the server and indentified bylocator
.- Parameters:
agent
- context for this Blob object (incl. connection)locator
- reference id to Blob value on server
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Method Details
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length
- Specified by:
length
in interfaceBlob
- Specified by:
length
in classLob
- Throws:
SQLException
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getLocatorLength
Get the length in bytes of theBlob
value represented by this locator basedobject. A stored procedure call will be made to get it from the server. - Overrides:
getLocatorLength
in classLob
- Returns:
- length of Blob in bytes
- Throws:
SqlException
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getBytes
Returns as an array of bytes part or all of theBLOB
value that thisBlob
object designates. The byte array contains up tolength
consecutive bytes starting at positionpos
. The starting position must be between 1 and the length of the BLOB plus 1. This allows for zero-length BLOB values, from which only zero-length byte arrays can be returned. If a larger length is requested than there are bytes available, characters from the start position to the end of the BLOB are returned.- Specified by:
getBytes
in interfaceBlob
- Parameters:
pos
- the ordinal position of the first byte in theBLOB
value to be extracted; the first byte is at position 1length
- is the number of consecutive bytes to be copied- Returns:
- a byte array containing up to
length
consecutive bytes from theBLOB
value designated by thisBlob
object, starting with the byte at positionstartPos
. - Throws:
SQLException
- if there is an error accessing theBLOB
NOTE: If the starting position is the length of the BLOB plus 1, zero bytess are returned regardless of the length requested.
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getBytesX
- Throws:
SqlException
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getBinaryStream
- Specified by:
getBinaryStream
in interfaceBlob
- Throws:
SQLException
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getBinaryStreamX
- Throws:
SqlException
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position
- Specified by:
position
in interfaceBlob
- Throws:
SQLException
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positionX
- Throws:
SqlException
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position
- Specified by:
position
in interfaceBlob
- Throws:
SQLException
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positionX
- Throws:
SqlException
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setBytes
- Specified by:
setBytes
in interfaceBlob
- Throws:
SQLException
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setBytes
- Specified by:
setBytes
in interfaceBlob
- Throws:
SQLException
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setBytesX
- Throws:
SqlException
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setBinaryStream
- Specified by:
setBinaryStream
in interfaceBlob
- Throws:
SQLException
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truncate
- Specified by:
truncate
in interfaceBlob
- Throws:
SQLException
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free
This method frees theBlob
object and releases the resources that it holds. The object is invalid once thefree
method is called. Iffree
is called multiple times, the subsequent calls tofree
are treated as a no-op.- Specified by:
free
in interfaceBlob
- Throws:
SQLException
- if an error occurs releasing the Blob's resources
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getBinaryStream
Returns anInputStream
object that contains a partialBlob
value, starting with the byte specified by pos, which is length bytes in length.- Specified by:
getBinaryStream
in interfaceBlob
- Parameters:
pos
- the offset to the first byte of the partial value to be retrieved. The first byte in theBlob
is at position 1.length
- the length in bytes of the partial value to be retrieved- Returns:
InputStream
through which the partialBlob
value can be read.- Throws:
SQLException
- if pos is less than 1 or if pos is greater than the number of bytes in theBlob
or ifpos + length
is greater thanBlob.length() +1
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isBinaryString
public boolean isBinaryString() -
isBinaryStream
public boolean isBinaryStream() -
binaryStringPosition
private long binaryStringPosition(byte[] pattern, long start) -
isSubString
private boolean isSubString(byte[] pattern, int index) -
materializeStream
Materialize the stream used for input to the database.- Specified by:
materializeStream
in classLob
- Throws:
SqlException
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