Class AbstractFbBlob
- java.lang.Object
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- org.firebirdsql.gds.ng.AbstractFbBlob
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- All Implemented Interfaces:
java.lang.AutoCloseable,FbBlob,DatabaseListener,ExceptionListenable,TransactionListener
- Direct Known Subclasses:
AbstractFbWireBlob,JnaBlob
public abstract class AbstractFbBlob extends java.lang.Object implements FbBlob, TransactionListener, DatabaseListener
Base class for low-level blob operations.- Since:
- 3.0
- Author:
- Mark Rotteveel
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected static classAbstractFbBlob.BlobStateState of the blob.-
Nested classes/interfaces inherited from interface org.firebirdsql.gds.ng.FbBlob
FbBlob.SeekMode
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Field Summary
Fields Modifier and Type Field Description protected ExceptionListenerDispatcherexceptionListenerDispatcher-
Fields inherited from interface org.firebirdsql.gds.ng.FbBlob
NO_BLOB_ID
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Constructor Summary
Constructors Modifier Constructor Description protectedAbstractFbBlob(FbDatabase database, FbTransaction transaction, BlobParameterBuffer blobParameterBuffer)
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidaddExceptionListener(ExceptionListener listener)Adds an exception listener to this object.voidcancel()Cancels an output blob (which means its contents will be thrown away).protected abstract voidcancelImpl()Internal implementation ofcancel().protected voidcheckBlobClosed()protected voidcheckBlobOpen()Checks if the blob is open.protected voidcheckDatabaseAttached()protected voidcheckTransactionActive()protected voidclearDatabase()protected voidclearDeferredException()Clears the deferred exception.protected voidclearTransaction()voidclose()Closes the blob.protected abstract voidcloseImpl()Internal implementation ofclose().protected BlobLengthProcessorcreateBlobLengthProcessor()voiddetached(FbDatabase database)Called when thedatabaseconnection has been detachedvoiddetaching(FbDatabase database)Called before thedatabasewill be detached.protected voiderrorOccurred(java.sql.SQLException e)intget(byte[] b, int off, int len)Reads content from the blob intobstarting atoffforlenbytes.intget(byte[] b, int off, int len, float minFillFactor)Variant ofFbBlob.get(byte[], int, int)to exert some control over the number of requests performed.protected abstract intget(byte[] b, int off, int len, int minLen)Default implementation forget(byte[], int, int)andget(byte[], int, int, float).<T> TgetBlobInfo(byte[] requestItems, int bufferLength, InfoProcessor<T> infoProcessor)Request blob info.protected BlobParameterBuffergetBlobParameterBuffer()FbDatabasegetDatabase()protected byte[]getKnownBlobInfoItems()The known blob info items for the connected server as a blob info request buffer.intgetMaximumSegmentSize()The maximum segment size allowed by the protocol forFbBlob.getSegment(int)andFbBlob.putSegment(byte[]).protected AbstractFbBlob.BlobStategetState()The current blob state.protected FbTransactiongetTransaction()protected booleanisEndingTransaction()booleanisEof()booleanisOpen()longlength()Requests the blob length from the server.voidputSegment(byte[] segment)Writes a segment of blob data.protected voidregisterDeferredException(java.sql.SQLException deferredException)Registers an exception as a deferred exception.protected abstract voidreleaseResources()Release Java resources held.voidremoveExceptionListener(ExceptionListener listener)Removes an exception listener to this object.protected voidresetEof()Resets the eof state of the blob to false (not eof).protected voidsetEof()Marks this blob as EOF (End of file).protected voidsetState(AbstractFbBlob.BlobState newState)Sets the state of the blob to the specified value.protected voidthrowAndClearDeferredException()If a deferred exception is registered it is cleared and thrown.voidtransactionStateChanged(FbTransaction transaction, TransactionState newState, TransactionState previousState)Signals that the transaction state changed.protected voidtransferDeferredExceptionTo(java.sql.SQLException target)If a deferred exception is registered, it is cleared and set as a next exception ontarget.voidwarningReceived(FbDatabase database, java.sql.SQLWarning warning)Called when a warning was received for thedatabaseconnection.protected LockCloseablewithLock()-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.firebirdsql.gds.ng.FbBlob
getBlobId, getBlobInfo, getHandle, getSegment, isOutput, open, put, seek
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Field Detail
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exceptionListenerDispatcher
protected final ExceptionListenerDispatcher exceptionListenerDispatcher
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Constructor Detail
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AbstractFbBlob
protected AbstractFbBlob(FbDatabase database, FbTransaction transaction, BlobParameterBuffer blobParameterBuffer) throws java.sql.SQLException
- Throws:
java.sql.SQLException
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Method Detail
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isOpen
public final boolean isOpen()
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isEof
public final boolean isEof()
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setEof
protected final void setEof()
Marks this blob as EOF (End of file).For an output blob this is a no-op (as those are never end of file, unless explicitly closed)
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resetEof
protected final void resetEof()
Resets the eof state of the blob to false (not eof).This method should only be called by subclasses of this class.
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setState
protected final void setState(AbstractFbBlob.BlobState newState)
Sets the state of the blob to the specified value.This method should only be called by subclasses of this class.
- Parameters:
newState- new value of state- Since:
- 5.0.7
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getState
protected final AbstractFbBlob.BlobState getState()
The current blob state.- Returns:
- current blob state
- Since:
- 5.0.7
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close
public final void close() throws java.sql.SQLExceptionDescription copied from interface:FbBlobCloses the blob.Closing an already closed blob is a no-op.
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closeImpl
protected abstract void closeImpl() throws java.sql.SQLExceptionInternal implementation ofclose(). The implementation does not need to check for attached database and active transaction, nor does it need to mark this blob as closed.- Throws:
java.sql.SQLException
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cancel
public final void cancel() throws java.sql.SQLExceptionDescription copied from interface:FbBlobCancels an output blob (which means its contents will be thrown away).Calling cancel on an input blob will close it. Contrary to
FbBlob.close(), calling cancel on an already closed (or cancelled) blob will throw anSQLException.
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cancelImpl
protected abstract void cancelImpl() throws java.sql.SQLExceptionInternal implementation ofcancel(). The implementation does not need to check for attached database and active transaction, nor does it need to mark this blob as closed.- Throws:
java.sql.SQLException
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putSegment
public void putSegment(byte[] segment) throws java.sql.SQLExceptionDescription copied from interface:FbBlobWrites a segment of blob data.Implementations must handle segment lengths exceeding
FbBlob.getMaximumSegmentSize()by batching. This method should either callput(segment, 0, segment.length), or produce the same effects as that call.Passing a section that is length 0 will throw an
SQLException.- Specified by:
putSegmentin interfaceFbBlob- Parameters:
segment- segment to write- Throws:
java.sql.SQLException- if this is an input blob, the blob is closed, the transaction is not active, the segment is length 0, or a database connection error occurred- See Also:
FbBlob.put(byte[], int, int)
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get
public final int get(byte[] b, int off, int len) throws java.sql.SQLExceptionDescription copied from interface:FbBlobReads content from the blob intobstarting atoffforlenbytes.Implementations must read the requested number of bytes (
len), unless end-of-blob is reached before the requested number of bytes were read. The return value of this method is the actual number of bytes read.If the implementation cannot perform reads without additional allocation, it should use at most
DatabaseConnectionProperties.getBlobBufferSize()as an internal buffer. If the implementation can perform reads without additional allocation, it is recommended it performs reads using (at most)FbBlob.getMaximumSegmentSize().Contrary to similar methods like
InputStream.read(byte[], int, int), this method returns0when no bytes were read if end-of-blob is reached without reading any bytes, not-1.Given this method attempts to fulfill the entire request for
lenbytes, it may not always be efficient. For example, requests near multiples of the maximum segment size (or blob buffer size) may result in a final request for just a few bytes. This is not a problem if the entire blob is requested at once, but for intermediate buffering it might be better not to do that final request, and instead work with a smaller number of bytes than requested. For those cases, useFbBlob.get(byte[], int, int, float).- Specified by:
getin interfaceFbBlob- Parameters:
b- target byte arrayoff- offset to startlen- number of bytes- Returns:
- actual number of bytes read; this will only be less than
lenwhen end-of-blob was reached - Throws:
java.sql.SQLException- for database access errors, ifoff < 0,len < 0, or ifoff + len > b.length
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get
public final int get(byte[] b, int off, int len, float minFillFactor) throws java.sql.SQLExceptionDescription copied from interface:FbBlobVariant ofFbBlob.get(byte[], int, int)to exert some control over the number of requests performed.This method will request segments until at least
(int) (minFillFactor * len)bytes have been retrieved, or end-of-blob is reached. This method is intended as an alternative toFbBlob.get(byte[], int, int)where avoiding the potential inefficiencies of that method are preferred over getting all the requestedlenbytes.If the implementation cannot perform reads without additional allocation, it should use at most
DatabaseConnectionProperties.getBlobBufferSize()as an internal buffer. If the implementation can perform reads without additional allocation, it is recommended it performs reads using (at most)FbBlob.getMaximumSegmentSize().Contrary to similar methods like
InputStream.read(byte[], int, int), this method returns0when no bytes were read if end-of-blob is reached without reading any bytes, not-1.- Specified by:
getin interfaceFbBlob- Parameters:
b- target byte arrayoff- offset to startlen- number of bytesminFillFactor- minimum fill factor (0 < minFillFactor <= 1)- Returns:
- actual number of bytes read, this method returns at least
(int) (minFillFactor * len)bytes, unless end-of-blob is reached - Throws:
java.sql.SQLException- for database access errors, ifoff < 0,len < 0, or ifoff + len > b.length,minFillFactor <= 0, orminFillFactor > 1orminFillFactor is NaN
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get
protected abstract int get(byte[] b, int off, int len, int minLen) throws java.sql.SQLExceptionDefault implementation forget(byte[], int, int)andget(byte[], int, int, float).- Parameters:
b- target byte arrayoff- offset to startlen- number of bytesminLen- minimum number of bytes to fill (must be0 < minLen <= leniflen != 0- Returns:
- actual number of bytes read; is
0iflen == 0, will only be less thanminLenif end-of-blob is reached - Throws:
java.sql.SQLException- for database access errors, ifoff < 0,len < 0, or ifoff + len > b.length, orlen != 0 && (minLen <= 0 || minLen > len)
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releaseResources
protected abstract void releaseResources()
Release Java resources held. This should not communicate with the Firebird server.
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registerDeferredException
protected final void registerDeferredException(java.sql.SQLException deferredException)
Registers an exception as a deferred exception.This should only be used for exceptions from deferred response that need to be thrown.
- Parameters:
deferredException- deferred exception- Since:
- 5.0.7
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clearDeferredException
protected final void clearDeferredException()
Clears the deferred exception.- Since:
- 5.0.7
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throwAndClearDeferredException
protected final void throwAndClearDeferredException() throws java.sql.SQLExceptionIf a deferred exception is registered it is cleared and thrown.- Throws:
java.sql.SQLException- the current deferred exception, if any- Since:
- 5.0.7
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transferDeferredExceptionTo
protected final void transferDeferredExceptionTo(java.sql.SQLException target)
If a deferred exception is registered, it is cleared and set as a next exception ontarget.- Parameters:
target- the target exception to add the deferred exception to (notnull)- Throws:
java.lang.NullPointerException- if there is a deferred exception, andtarget == null- Since:
- 5.0.7
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withLock
protected final LockCloseable withLock()
- See Also:
FbAttachment.withLock()
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transactionStateChanged
public void transactionStateChanged(FbTransaction transaction, TransactionState newState, TransactionState previousState)
Description copied from interface:TransactionListenerSignals that the transaction state changed.- Specified by:
transactionStateChangedin interfaceTransactionListener- Parameters:
transaction-FbTransactionthat changed state
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detaching
public void detaching(FbDatabase database)
Description copied from interface:DatabaseListenerCalled before thedatabasewill be detached.This event is intended for cleanup action, implementer should take care that no exceptions are thrown from this method.
- Specified by:
detachingin interfaceDatabaseListener- Parameters:
database- The database object that is detaching
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detached
public void detached(FbDatabase database)
Description copied from interface:DatabaseListenerCalled when thedatabaseconnection has been detached- Specified by:
detachedin interfaceDatabaseListener- Parameters:
database- The database object that was detached
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warningReceived
public void warningReceived(FbDatabase database, java.sql.SQLWarning warning)
Description copied from interface:DatabaseListenerCalled when a warning was received for thedatabaseconnection.In implementation it is possible that some warnings are not sent to listeners on the database, but only to listeners on specific connection derived objects (like an
FbStatementimplementation).- Specified by:
warningReceivedin interfaceDatabaseListener- Parameters:
database- Database receiving the warningwarning- Warning
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isEndingTransaction
protected final boolean isEndingTransaction()
- Returns:
trueif the transaction is committing, rolling back or preparing
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checkTransactionActive
protected final void checkTransactionActive() throws java.sql.SQLException- Throws:
java.sql.SQLException- when no transaction is set, or the transaction state is notTransactionState.ACTIVE
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checkDatabaseAttached
protected final void checkDatabaseAttached() throws java.sql.SQLException- Throws:
java.sql.SQLException- when no database is set, or the database is not attached
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checkBlobOpen
protected void checkBlobOpen() throws java.sql.SQLExceptionChecks if the blob is open.NOTE: Subclasses may perform additional side effects, like queuing a server-side open for a deferred open blob.
- Throws:
java.sql.SQLException- when the blob is closed.
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checkBlobClosed
protected void checkBlobClosed() throws java.sql.SQLException- Throws:
java.sql.SQLException- when the blob is open.
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getTransaction
protected FbTransaction getTransaction()
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clearTransaction
protected final void clearTransaction()
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getDatabase
public FbDatabase getDatabase()
- Specified by:
getDatabasein interfaceFbBlob- Returns:
- The database connection that created this blob
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getBlobInfo
public <T> T getBlobInfo(byte[] requestItems, int bufferLength, InfoProcessor<T> infoProcessor) throws java.sql.SQLExceptionDescription copied from interface:FbBlobRequest blob info.- Specified by:
getBlobInfoin interfaceFbBlob- Parameters:
requestItems- Array of info items to requestbufferLength- Response buffer length to useinfoProcessor- Implementation ofInfoProcessorto transform the info response- Returns:
- Transformed info response of type T
- Throws:
java.sql.SQLException- For errors retrieving or transforming the response.
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getKnownBlobInfoItems
protected byte[] getKnownBlobInfoItems()
The known blob info items for the connected server as a blob info request buffer.- Returns:
- the known blob info items (possibly empty under implementation-specific circumstances)
- Since:
- 5.0.7
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length
public long length() throws java.sql.SQLExceptionDescription copied from interface:FbBlobRequests the blob length from the server.
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errorOccurred
protected final void errorOccurred(java.sql.SQLException e)
NotifiesExceptionListenerDispatcher.errorOccurred(SQLException).If there is a registered deferred exception, it is set as a next exception on
ebefore notification.- Parameters:
e- exception to notify to exception listeners
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addExceptionListener
public final void addExceptionListener(ExceptionListener listener)
Description copied from interface:ExceptionListenableAdds an exception listener to this object.Implementations use
WeakReference.- Specified by:
addExceptionListenerin interfaceExceptionListenable- Parameters:
listener- Listener to register
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removeExceptionListener
public final void removeExceptionListener(ExceptionListener listener)
Description copied from interface:ExceptionListenableRemoves an exception listener to this object.- Specified by:
removeExceptionListenerin interfaceExceptionListenable- Parameters:
listener- Listener to remove
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clearDatabase
protected final void clearDatabase()
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getBlobParameterBuffer
protected BlobParameterBuffer getBlobParameterBuffer()
- Returns:
- The blob parameter buffer of this blob.
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createBlobLengthProcessor
protected BlobLengthProcessor createBlobLengthProcessor()
- Returns:
- New instance of
BlobLengthProcessorfor this blob.
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getMaximumSegmentSize
public int getMaximumSegmentSize()
Description copied from interface:FbBlobThe maximum segment size allowed by the protocol forFbBlob.getSegment(int)andFbBlob.putSegment(byte[]).This value is not the segment size (optionally) defined for the column.
- Specified by:
getMaximumSegmentSizein interfaceFbBlob- Returns:
- The maximum segment size allowed for get or put.
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