java.lang.Object
- org.hsqldb.jdbc.JDBCBlob

All Implemented Interfaces:

java.sql.Blob
```
public class JDBCBlob
extends java.lang.Object
implements java.sql.Blob
```
The representation (mapping) in the Java™ 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. By default drivers implement 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 it was created.
Methods in the interfaces ResultSet, CallableStatement, and 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. In addition, this interface has methods for updating a BLOB value.
All methods on the Blob interface must be fully implemented if the JDBC driver supports the data type.

HSQLDB-Specific Information:

Previous to 2.0, the HSQLDB driver did not implement Blob using an SQL locator(BLOB). That is, an HSQLDB Blob object did not contain a logical pointer to SQL BLOB data; rather it directly contained a representation of the data (a byte array). As a result, an HSQLDB Blob object was itself valid beyond the duration of the transaction in which is was created, although it did not necessarily represent a corresponding value on the database. Also, the interface methods for updating a BLOB value were unsupported, with the exception of the truncate method, in that it could be used to truncate the local value.
Starting with 2.0, the HSQLDB driver fully supports both local and remote SQL BLOB data implementations, meaning that an HSQLDB Blob object may contain a logical pointer to remote SQL BLOB data (see JDBCBlobClient) or it may directly contain a local representation of the data (as implemented in this class). In particular, when the product is built under JDK 1.6+ and the Blob instance is constructed as a result of calling JDBCConnection.createBlob(), then the resulting Blob instance is initially disconnected (is not bound to the transaction scope of the vending Connection object), the data is contained directly and all interface methods for updating the BLOB value are supported for local use until the first invocation of free(); otherwise, an HSQLDB Blob's implementation is determined at runtime by the driver, it is typically not valid beyond the duration of the transaction in which is was created, and there no standard way to query whether it represents a local or remote value.

Since:

JDK 1.2, HSQLDB 1.7.2

Author:

james house (jhouse@part.net), Campbell Burnet (campbell-burnet@users dot sourceforge.net)

Constructor Summary

Constructors
Constructor Description

JDBCBlob(byte[] data)
Constructs a new JDBCBlob instance wrapping the given octet sequence.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`free()`	This method frees the `Blob` object and releases the resources that it holds.
`java.io.InputStream`	`getBinaryStream()`	Retrieves the `BLOB` value designated by this `Blob` instance as a stream.
`java.io.InputStream`	`getBinaryStream(long pos, long length)`	Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
`byte[]`	`getBytes(long pos, int length)`	Retrieves all or part of the `BLOB` value that this `Blob` object represents, as an array of bytes.
`long`	`length()`	Returns the number of bytes in the `BLOB` value designated by this `Blob` object.
`long`	`position(byte[] pattern, long start)`	Retrieves the byte position at which the specified byte array `pattern` begins within the `BLOB` value that this `Blob` object represents.
`long`	`position(java.sql.Blob pattern, long start)`	Retrieves the byte position in the `BLOB` value designated by this `Blob` object at which `pattern` begins.
`java.io.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 pos, byte[] bytes)`	Writes the given array of bytes to the `BLOB` value that this `Blob` object represents, starting at position `pos`, and returns the number of bytes written.
`int`	`setBytes(long pos, byte[] bytes, int offset, int len)`	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 len)`	Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - JDBCBlob
```
public JDBCBlob(byte[] data)
         throws java.sql.SQLException
```
    Constructs a new JDBCBlob instance wrapping the given octet sequence.
    This constructor is used internally to retrieve result set values as Blob objects, yet it must be public to allow access from other packages. As such (in the interest of efficiency) this object maintains a reference to the given octet sequence rather than making a copy; special care should be taken by external clients never to use this constructor with a byte array object that may later be modified externally.
    
    Parameters:
    
    data - the octet sequence representing the Blob value
    
    Throws:
    
    java.sql.SQLException - if the argument is null
- Method Detail
  - length
```
public long length()
            throws java.sql.SQLException
```
    Returns the number of bytes in the BLOB value designated by this Blob object.
    
    Specified by:
    
    length in interface java.sql.Blob
    
    Returns:
    
    length of the BLOB in bytes
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the length of the BLOB
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.2, HSQLDB 1.7.2
  - getBytes
```
public byte[] getBytes(long pos,
                       int length)
                throws java.sql.SQLException
```
    Retrieves all or part of the BLOB value that this Blob object represents, as an array of bytes. This byte array contains up to length consecutive bytes starting at position pos.
    
    HSQLDB-Specific Information:
    
    The official specification above is ambiguous in that it does not precisely indicate the policy to be observed when pos > this.length() - length. One policy would be to retrieve the octets from pos to this.length(). Another would be to throw an exception. HSQLDB observes the second policy.
    
    Specified by:
    
    getBytes in interface java.sql.Blob
    
    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; JDBC 4.1[the value for length must be 0 or greater]
    
    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
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value; if pos is less than 1 or length is less than 0
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.2, HSQLDB 1.7.2
    
    See Also:
    
    setBytes(long, byte[])
  - getBinaryStream
```
public java.io.InputStream getBinaryStream()
                                    throws java.sql.SQLException
```
    Retrieves the BLOB value designated by this Blob instance as a stream.
    
    Specified by:
    
    getBinaryStream in interface java.sql.Blob
    
    Returns:
    
    a stream containing the BLOB data
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.2, HSQLDB 1.7.2
    
    See Also:
    
    setBinaryStream(long)
  - position
```
public long position(byte[] pattern,
                     long start)
              throws java.sql.SQLException
```
    Retrieves the byte position at which the specified byte array pattern begins within the BLOB value that this Blob object represents. The search for pattern begins at position start.
    
    Specified by:
    
    position in interface java.sql.Blob
    
    Parameters:
    
    pattern - the byte array for which to search
    
    start - the position at which to begin searching; the first position is 1
    
    Returns:
    
    the position at which the pattern appears, else -1
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB or if start is less than 1
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.2, HSQLDB 1.7.2
  - position
```
public long position(java.sql.Blob pattern,
                     long start)
              throws java.sql.SQLException
```
    Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.
    
    Specified by:
    
    position in interface java.sql.Blob
    
    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
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value or if start is less than 1
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.2, HSQLDB 1.7.2
  - setBytes
```
public int setBytes(long pos,
                    byte[] bytes)
             throws java.sql.SQLException
```
    Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written. The array of bytes will overwrite the existing bytes in the Blob object starting at the position pos. If the end of the Blob value is reached while writing the array of bytes, then the length of the Blob value will be increased to accommodate the extra bytes.
    Note: If the value specified for pos is greater than the length+1 of the BLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.
    
    HSQLDB-Specific Information:
    
    Starting with HSQLDB 2.0 this feature is supported.
    When built under JDK 1.6+ and the Blob instance is constructed as a result of calling JDBCConnection.createBlob(), this operation affects only the client-side value; it has no effect upon a value stored in a database because JDBCConnection.createBlob() constructs disconnected, initially empty Blob instances. To propagate the Blob value to a database in this case, it is required to supply the Blob instance to an updating or inserting setXXX method of a Prepared or Callable Statement, or to supply the Blob instance to an updateXXX method of an updatable ResultSet.
    Implementation Notes:
    Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields and is effectively thread safe, but still uses local variable snapshot isolation.
    As such, the synchronization policy still does not strictly enforce serialized read/write access to the underlying data
    So, if an application may perform concurrent JDBCBlob modifications and the integrity of the application depends on total order Blob modification semantics, then such operations should be synchronized on an appropriate monitor.
    
    Specified by:
    
    setBytes in interface java.sql.Blob
    
    Parameters:
    
    pos - the position in the BLOB object at which to start writing; the first position is 1
    
    bytes - the array of bytes to be written to the BLOB value that this Blob object represents
    
    Returns:
    
    the number of bytes written
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value or if pos is less than 1
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.4, HSQLDB 1.7.2
    
    See Also:
    
    getBytes(long, int)
  - setBytes
```
public int setBytes(long pos,
                    byte[] bytes,
                    int offset,
                    int len)
             throws java.sql.SQLException
```
    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. Writing starts at position pos in the BLOB value; len bytes from the given byte array are written. The array of bytes will overwrite the existing bytes in the Blob object starting at the position pos. If the end of the Blob value is reached while writing the array of bytes, then the length of the Blob value will be increased to accommodate the extra bytes.
    Note: If the value specified for pos is greater than the length+1 of the BLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.
    
    HSQLDB-Specific Information:
    
    Starting with HSQLDB 2.0 this feature is supported.
    When built under JDK 1.6+ and the Blob instance is constructed as a result of calling JDBCConnection.createBlob(), this operation affects only the client-side value; it has no effect upon a value stored in a database because JDBCConnection.createBlob() constructs disconnected, initially empty Blob instances. To propagate the Blob value to a database in this case, it is required to supply the Blob instance to an updating or inserting setXXX method of a Prepared or Callable Statement, or to supply the Blob instance to an updateXXX method of an updatable ResultSet.
    Implementation Notes:
    If the value specified for pos is greater than the length of the BLOB value, then the BLOB value is extended in length to accept the written octets and the undefined region up to pos is filled with (byte)0.
    Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields and is effectively thread safe, but still uses local variable snapshot isolation.
    As such, the synchronization policy still does not strictly enforce serialized read/write access to the underlying data
    So, if an application may perform concurrent JDBCBlob modifications and the integrity of the application depends on total order Blob modification semantics, then such operations should be synchronized on an appropriate monitor.
    
    Specified by:
    
    setBytes in interface java.sql.Blob
    
    Parameters:
    
    pos - the position in the BLOB object at which to start writing; the first position is 1
    
    bytes - the array of bytes to be written to this BLOB object
    
    offset - the offset into the array bytes at which to start reading the bytes to be set
    
    len - the number of bytes to be written to the BLOB value from the array of bytes bytes
    
    Returns:
    
    the number of bytes written
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value or if pos is less than 1
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.4, HSQLDB 1.7.2
    
    See Also:
    
    getBytes(long, int)
  - setBinaryStream
```
public java.io.OutputStream setBinaryStream(long pos)
                                     throws java.sql.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. The bytes written to the stream will overwrite the existing bytes in the Blob object starting at the position pos. If the end of the Blob value is reached while writing to the stream, then the length of the Blob value will be increased to accommodate the extra bytes.
    Note: If the value specified for pos is greater than the length+1 of the BLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.
    
    HSQLDB-Specific Information:
    
    Starting with HSQLDB 2.0 this feature is supported.
    When built under JDK 1.6+ and the Blob instance is constructed as a result of calling JDBCConnection.createBlob(), this operation affects only the client-side value; it has no effect upon a value stored in a database because JDBCConnection.createBlob() constructs disconnected, initially empty Blob instances. To propagate the Blob value to a database in this case, it is required to supply the Blob instance to an updating or inserting setXXX method of a Prepared or Callable Statement, or to supply the Blob instance to an updateXXX method of an updatable ResultSet.
    Implementation Notes:
    The data written to the stream does not appear in this Blob until the stream is closed
    When the stream is closed, if the value specified for pos is greater than the length of the BLOB value, then the BLOB value is extended in length to accept the written octets and the undefined region up to pos is filled with (byte)0.
    Starting with HSQLDB 2.1, JDBCBlob no longer utilizes volatile fields and is effectively thread safe, but still uses local variable snapshot isolation.
    As such, the synchronization policy still does not strictly enforce serialized read/write access to the underlying data
    So, if an application may perform concurrent JDBCBlob modifications and the integrity of the application depends on total order Blob modification semantics, then such operations should be synchronized on an appropriate monitor.
    
    Specified by:
    
    setBinaryStream in interface java.sql.Blob
    
    Parameters:
    
    pos - the position in the BLOB value at which to start writing; the first position is 1
    
    Returns:
    
    a java.io.OutputStream object to which data can be written
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value or if pos is less than 1
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.4, HSQLDB 1.7.2
    
    See Also:
    
    getBinaryStream()
  - truncate
```
public void truncate(long len)
              throws java.sql.SQLException
```
    Truncates the BLOB value that this Blob object represents to be len bytes in length.
    Note: If the value specified for pos is greater than the length+1 of the BLOB value then the behavior is undefined. Some JDBC drivers may throw a SQLException while other drivers may support this operation.
    
    HSQLDB-Specific Information:
    
    Starting with HSQLDB 2.0 this feature is fully supported.
    When built under JDK 1.6+ and the Blob instance is constructed as a result of calling JDBCConnection.createBlob(), this operation affects only the client-side value; it has no effect upon a value stored in a database because JDBCConnection.createBlob() constructs disconnected, initially empty Blob instances. To propagate the truncated Blob value to a database in this case, it is required to supply the Blob instance to an updating or inserting setXXX method of a Prepared or Callable Statement, or to supply the Blob instance to an updateXXX method of an updateable ResultSet.
    
    Specified by:
    
    truncate in interface java.sql.Blob
    
    Parameters:
    
    len - the length, in bytes, to which the BLOB value that this Blob object represents should be truncated
    
    Throws:
    
    java.sql.SQLException - if there is an error accessing the BLOB value or if len is less than 0
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.4, HSQLDB 1.7.2
  - free
```
public void free()
          throws java.sql.SQLException
```
    This method frees the Blob object and releases the resources that it holds. The object is invalid once the free method is called.
    After free has been called, any attempt to invoke a method other than free will result in a SQLException being thrown. If free is called multiple times, the subsequent calls to free are treated as a no-op.
    
    Specified by:
    
    free in interface java.sql.Blob
    
    Throws:
    
    java.sql.SQLException - if an error occurs releasing the Blob's resources
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.6, HSQLDB 2.0
  - getBinaryStream
```
public java.io.InputStream getBinaryStream(long pos,
                                           long length)
                                    throws java.sql.SQLException
```
    Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.
    
    Specified by:
    
    getBinaryStream in interface java.sql.Blob
    
    Parameters:
    
    pos - the offset to the first byte of the partial value to be retrieved. The first byte in the Blob is at position 1
    
    length - the length in bytes of the partial value to be retrieved
    
    Returns:
    
    InputStream through which the partial Blob value can be read.
    
    Throws:
    
    java.sql.SQLException - if pos is less than 1 or if pos is greater than the number of bytes in the Blob or if pos + length is greater than the number of bytes in the Blob
    
    java.sql.SQLFeatureNotSupportedException - if the JDBC driver does not support this method
    
    Since:
    
    JDK 1.6, HSQLDB 2.0

Class JDBCBlob

HSQLDB-Specific Information:

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

JDBCBlob

Method Detail

length

getBytes

HSQLDB-Specific Information:

getBinaryStream

position

position

setBytes

HSQLDB-Specific Information:

setBytes

HSQLDB-Specific Information:

setBinaryStream

HSQLDB-Specific Information:

truncate

HSQLDB-Specific Information:

free

getBinaryStream