org.firebirdsql.jdbc

Class FBBlob

java.lang.Object
- org.firebirdsql.jdbc.FBBlob

Implemented Interfaces:: Blob, FirebirdBlob, Synchronizable

public class FBBlob

extends java.lang.Object

implements FirebirdBlob, Synchronizable

The representation (mapping) in the Java^TM programming language of an SQL BLOB value. An SQL BLOB is a built-in type that stores a Binary Large Object as a column value in a row of a database table. The driver implements Blob using an SQL locator(BLOB), which means that a Blob object contains a logical pointer to the SQL BLOB data rather than the data itself. A Blob object is valid for the duration of the transaction in which is was created.

Methods in the interfaces java.sql.ResultSet, java.sql.CallableStatement, and java.sql.PreparedStatement, such as getBlob and setBlob allow a programmer to access an SQL BLOB value. The Blob interface provides methods for getting the length of an SQL BLOB (Binary Large Object) value, for materializing a BLOB value on the client, and for determining the position of a pattern of bytes within a BLOB value.

This class is new in the JDBC 2.0 API.

Since:: 1.2

Nested Class Summary
`class`	`FBBlob.FBBlobInputStream` An input stream for reading directly from a FBBlob instance.
`class`	`FBBlob.FBBlobOutputStream`

Field Summary
`static byte[]`	`BLOB_LENGTH_REQUEST`
`static int`	`READ_FULLY_BUFFER_SIZE`
`static boolean`	`SEGMENTED`

Constructor Summary
`FBBlob(org.firebirdsql.gds.impl.GDSHelper c)`
`FBBlob(org.firebirdsql.gds.impl.GDSHelper c, long blob_id)`
`FBBlob(org.firebirdsql.gds.impl.GDSHelper c, long blob_id, FBObjectListener.BlobListener blobListener)` Create instance of this class to access existing Blob.
`FBBlob(org.firebirdsql.gds.impl.GDSHelper c, FBObjectListener.BlobListener blobListener)` Create new Blob instance.

Method Summary
`void`	`close()` Close this Blob object.
`void`	`copyBytes(byte[] bytes, int pos, int len)`
`void`	`copyCharacterStream(Reader inputStream, int length, String encoding)` Copy data from a character stream into this Blob.
`void`	`copyStream(InputStream inputStream)` Copy the contents of an `InputStream` into this Blob.
`void`	`copyStream(InputStream inputStream, int length)` Copy the contents of an `InputStream` into this Blob.
`FirebirdBlob`	`detach()` Detach this blob.
`InputStream`	`getBinaryStream()` Retrieves the `BLOB` designated by this `Blob` instance as a stream.
`long`	`getBlobId()` Get the identifier for this `Blob`
`byte[]`	`getBytes(long pos, int length)` Returns as an array of bytes, part or all of the `BLOB` value that this `Blob` object designates.
`byte[]`	`getInfo(byte[] items, int buffer_length)` Get information about this Blob.
`Object`	`getSynchronizationObject()` Get synchronization object that will be used to synchronize multithreaded access to the database.
`static long`	`interpretLength(GDS gds, byte[] info, int position)` Interpret BLOB length from buffer.
`boolean`	`isSegmented()` Check if blob is segmented.
`long`	`length()` Returns the number of bytes in the `BLOB` value designated by this `Blob` object.
`long`	`position(Blob pattern, long start)` Determines the byte position in the `BLOB` value designated by this `Blob` object at which `pattern` begins.
`long`	`position(pattern[] , long start)` Determines the byte position at which the specified byte `pattern` begins within the `BLOB` value that this `Blob` object represents.
`OutputStream`	`setBinaryStream(long pos)` Retrieves a stream that can be used to write to the BLOB value that this Blob object represents.
`int`	`setBytes(long param1, byte[] param2)` This operation is not currently supported Writes all or part of the given byte array to the BLOB value that this `Blob` object represents and returns the number of bytes written.
`int`	`setBytes(long param1, byte[] param2, int param3, int param4)` This operation is not currently supported Writes all or part of the given byte array to the BLOB value that this `Blob` object represents and returns the number of bytes written.
`void`	`truncate(long param1)` This operation is not currently supported Truncate this `Blob` to a given length.

BLOB_LENGTH_REQUEST

public static final byte[] BLOB_LENGTH_REQUEST

READ_FULLY_BUFFER_SIZE

public static final int READ_FULLY_BUFFER_SIZE

Field Value:
16384

SEGMENTED

public static final boolean SEGMENTED

Field Value:
true

FBBlob

public FBBlob(org.firebirdsql.gds.impl.GDSHelper c)

FBBlob

public FBBlob(org.firebirdsql.gds.impl.GDSHelper c,
              long blob_id)

FBBlob

public FBBlob(org.firebirdsql.gds.impl.GDSHelper c,
              long blob_id,
              FBObjectListener.BlobListener blobListener)

Create instance of this class to access existing Blob.
Parameters:
c - connection that will be used to access Blob.
blob_id - ID of the Blob.

FBBlob

public FBBlob(org.firebirdsql.gds.impl.GDSHelper c,
              FBObjectListener.BlobListener blobListener)

Create new Blob instance. This constructor creates new fresh Blob, only writing to the Blob is allowed.
Parameters:
c - connection that will be used to write data to blob.

close

public void close()
            throws IOException

Close this Blob object. This method closes all open input streams.

copyBytes

public void copyBytes(byte[] bytes,
                      int pos,
                      int len)
            throws SQLException

copyCharacterStream

public void copyCharacterStream(Reader inputStream,
                                int length,
                                String encoding)
            throws SQLException

Copy data from a character stream into this Blob.
Parameters:
inputStream - the source of data to copy
length - The maximum number of bytes to copy
encoding - The encoding used in the character stream

copyStream

public void copyStream(InputStream inputStream)
            throws SQLException

Copy the contents of an InputStream into this Blob. Unlike the copyStream(InputStream,int) method, this one copies bytes until the EOF is reached.
Parameters:
inputStream - the stream from which data will be copied

copyStream

public void copyStream(InputStream inputStream,
                       int length)
            throws SQLException

Copy the contents of an InputStream into this Blob.
Parameters:
inputStream - the stream from which data will be copied
length - The maximum number of bytes to read from the InputStream

detach

public FirebirdBlob detach()
            throws SQLException

Detach this blob. This method creates new instance of the same blob database object that is not under result set control. When result set is closed, all associated resources are also released, including open blob streams. This method creates an new instance of blob object with the same blob ID that can be used even when result set is closed.
Note, detached blob will not remember the stream position of this object. This means that you cannot start reading data from the blob, then detach it, and then continue reading. Reading from detached blob will begin at the blob start.
Specified by:
detach in interface FirebirdBlob
Returns:
instance of FBBlob that is not under result set control.

getBinaryStream

public InputStream getBinaryStream()
            throws SQLException

Retrieves the BLOB designated by this Blob instance as a stream.
Returns:
a stream containing the BLOB data
Since:
1.2
See Also:
What Is in the JDBC 2.0 API

getBlobId

public long getBlobId()
            throws SQLException

Get the identifier for this Blob
Returns:
This Blob's identifier

getBytes

public byte[] getBytes(long pos,
                       int length)
            throws SQLException

Returns as an array of bytes, part or all of the BLOB value that this Blob object designates. The byte array contains up to length consecutive bytes starting at position pos.
Parameters:
pos - the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1
length - the number of consecutive bytes to be copied
Returns:
a byte array containing up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos
Since:
1.2
See Also:
What Is in the JDBC 2.0 API

getInfo

public byte[] getInfo(byte[] items,
                      int buffer_length)
            throws SQLException

Get information about this Blob. This method should be considered as temporary because it provides access to low-level API. More information on how to use the API can be found in "API Guide".
Parameters:
items - items in which we are interested.
buffer_length - buffer where information will be stored.
Returns:
array of bytes containing information about this Blob.

getSynchronizationObject

public Object getSynchronizationObject()

Get synchronization object that will be used to synchronize multithreaded access to the database.
Specified by:
getSynchronizationObject in interface Synchronizable
Returns:
object that will be used for synchronization.

interpretLength

public static long interpretLength(GDS gds,
                                   byte[] info,
                                   int position)
            throws SQLException

Interpret BLOB length from buffer.
Parameters:
info - server response.
position - where to start interpreting.
Returns:
length of the blob.

isSegmented

public boolean isSegmented()
            throws SQLException

Check if blob is segmented.
Specified by:
isSegmented in interface FirebirdBlob
Returns:
true if this blob is segmented, otherwise false

length

public long length()
            throws SQLException

Returns the number of bytes in the BLOB value designated by this Blob object.
Returns:
length of the BLOB in bytes
Since:
1.2
See Also:
What Is in the JDBC 2.0 API

position

public long position(Blob pattern,
                     long start)
            throws SQLException

Determines the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.
Parameters:
pattern - the Blob object designating the BLOB value for which to search
start - the position in the BLOB value at which to begin searching; the first position is 1
Returns:
the position at which the pattern begins, else -1
Since:
1.2
See Also:
What Is in the JDBC 2.0 API

position

public long position(pattern[] ,
                     long start)
            throws SQLException

Determines the byte position at which the specified byte pattern begins within the BLOB value that this Blob object represents. The search for pattern begins at position start.
Parameters:
start - the position at which to begin searching; the first position is 1
Returns:
the position at which the pattern appears, else -1
Since:
1.2
See Also:
What Is in the JDBC 2.0 API

setBinaryStream

public OutputStream setBinaryStream(long pos)
            throws SQLException

Retrieves a stream that can be used to write to the BLOB value that this Blob object represents. The stream begins at position pos.
Specified by:
setBinaryStream in interface FirebirdBlob
Parameters:
pos - The position in the blob to start writing.
Returns:
OuputStream to write to.

setBytes

public int setBytes(long param1,
                    byte[] param2)
            throws SQLException

This operation is not currently supported Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
Parameters:
param1 - The position at which to start writing
param2 - The array of bytes to be written
Returns:
the number of bytes written

setBytes

public int setBytes(long param1,
                    byte[] param2,
                    int param3,
                    int param4)
            throws SQLException

This operation is not currently supported Writes all or part of the given byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
Parameters:
param1 - The position at which to start writing
param2 - The array of bytes to be written
param3 - the offset into the byte array at which to start reading the bytes to be set
param4 - the number of bytes to be written to the BLOB value from the byte array
Returns:
the number of bytes written

truncate

public void truncate(long param1)
            throws SQLException

This operation is not currently supported Truncate this Blob to a given length.
Parameters:
param1 - The length to truncate this Blob to

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org.firebirdsql.jdbc

Class FBBlob

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Field Details

BLOB_LENGTH_REQUEST

READ_FULLY_BUFFER_SIZE

SEGMENTED

Constructor Details

FBBlob

FBBlob

FBBlob

FBBlob

Method Details

close

copyBytes

copyCharacterStream

copyStream

copyStream

detach

getBinaryStream

getBlobId

getBytes

getInfo

getSynchronizationObject

interpretLength

isSegmented

length

position

position

setBinaryStream

setBytes

setBytes

truncate