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package java.sql;

import java.io.InputStream;

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 is 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.

Since:1.2
/** * The representation (mapping) in * the Java&trade; programming language of an SQL * {@code BLOB} value. An SQL {@code 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 {@code Blob} using * an SQL {@code locator(BLOB)}, which means that a * {@code Blob} object contains a logical pointer to the * SQL {@code BLOB} data rather than the data itself. * A {@code Blob} object is valid for the duration of the * transaction in which is was created. * * <P>Methods in the interfaces {@link ResultSet}, * {@link CallableStatement}, and {@link PreparedStatement}, such as * {@code getBlob} and {@code setBlob} allow a programmer to * access an SQL {@code BLOB} value. * The {@code Blob} interface provides methods for getting the * length of an SQL {@code BLOB} (Binary Large Object) value, * for materializing a {@code BLOB} value on the client, and for * determining the position of a pattern of bytes within a * {@code BLOB} value. In addition, this interface has methods for updating * a {@code BLOB} value. * <p> * All methods on the {@code Blob} interface must be fully implemented if the * JDBC driver supports the data type. * * @since 1.2 */
public interface Blob {
Returns the number of bytes in the BLOB value designated by this Blob object.
Throws:
Returns:length of the BLOB in bytes
Since:1.2
/** * Returns the number of bytes in the {@code BLOB} value * designated by this {@code Blob} object. * * @return length of the {@code BLOB} in bytes * @exception SQLException if there is an error accessing the * length of the {@code BLOB} * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */
long length() throws 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.
Params:
  • 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; the value for length must be 0 or greater
Throws:
See Also:
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
/** * Retrieves all or part of the {@code BLOB} * value that this {@code Blob} object represents, as an array of * bytes. This {@code byte} array contains up to {@code length} * consecutive bytes starting at position {@code pos}. * * @param pos the ordinal position of the first byte in the * {@code BLOB} value to be extracted; the first byte is at * position 1 * @param length the number of consecutive bytes to be copied; the value * for length must be 0 or greater * @return a byte array containing up to {@code length} * consecutive bytes from the {@code BLOB} value designated * by this {@code Blob} object, starting with the * byte at position {@code pos} * @exception SQLException if there is an error accessing the * {@code BLOB} value; if pos is less than 1 or length is * less than 0 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #setBytes * @since 1.2 */
byte[] getBytes(long pos, int length) throws SQLException;
Retrieves the BLOB value designated by this Blob instance as a stream.
Throws:
See Also:
Returns:a stream containing the BLOB data
Since:1.2
/** * Retrieves the {@code BLOB} value designated by this * {@code Blob} instance as a stream. * * @return a stream containing the {@code BLOB} data * @exception SQLException if there is an error accessing the * {@code BLOB} value * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #setBinaryStream * @since 1.2 */
java.io.InputStream getBinaryStream () throws 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.
Params:
  • pattern – the byte array for which to search
  • start – the position at which to begin searching; the first position is 1
Throws:
Returns:the position at which the pattern appears, else -1
Since:1.2
/** * Retrieves the byte position at which the specified byte array * {@code pattern} begins within the {@code BLOB} * value that this {@code Blob} object represents. * The search for {@code pattern} begins at position * {@code start}. * * @param pattern the byte array for which to search * @param start the position at which to begin searching; the * first position is 1 * @return the position at which the pattern appears, else -1 * @exception SQLException if there is an error accessing the * {@code BLOB} or if start is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */
long position(byte pattern[], long start) throws SQLException;
Retrieves the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.
Params:
  • 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
Throws:
Returns:the position at which the pattern begins, else -1
Since:1.2
/** * Retrieves the byte position in the {@code BLOB} value * designated by this {@code Blob} object at which * {@code pattern} begins. The search begins at position * {@code start}. * * @param pattern the {@code Blob} object designating * the {@code BLOB} value for which to search * @param start the position in the {@code BLOB} value * at which to begin searching; the first position is 1 * @return the position at which the pattern begins, else -1 * @exception SQLException if there is an error accessing the * {@code BLOB} value or if start is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.2 */
long position(Blob pattern, long start) throws SQLException; // -------------------------- JDBC 3.0 -----------------------------------
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 an SQLException while other drivers may support this operation.

Params:
  • 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
Throws:
See Also:
Returns:the number of bytes written
Since:1.4
/** * Writes the given array of bytes to the {@code BLOB} value that * this {@code Blob} object represents, starting at position * {@code pos}, and returns the number of bytes written. * The array of bytes will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing the array of bytes, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} value then the * behavior is undefined. Some JDBC drivers may throw an * {@code SQLException} while other drivers may support this * operation. * * @param pos the position in the {@code BLOB} object at which * to start writing; the first position is 1 * @param bytes the array of bytes to be written to the {@code BLOB} * value that this {@code Blob} object represents * @return the number of bytes written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBytes * @since 1.4 */
int setBytes(long pos, byte[] bytes) throws 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 an SQLException while other drivers may support this operation.

Params:
  • 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
Throws:
See Also:
Returns:the number of bytes written
Since:1.4
/** * Writes all or part of the given {@code byte} array to the * {@code BLOB} value that this {@code Blob} object represents * and returns the number of bytes written. * Writing starts at position {@code pos} in the {@code BLOB} * value; {@code len} bytes from the given byte array are written. * The array of bytes will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing the array of bytes, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} value then the * behavior is undefined. Some JDBC drivers may throw an * {@code SQLException} while other drivers may support this * operation. * * @param pos the position in the {@code BLOB} object at which * to start writing; the first position is 1 * @param bytes the array of bytes to be written to this {@code BLOB} * object * @param offset the offset into the array {@code bytes} at which * to start reading the bytes to be set * @param len the number of bytes to be written to the {@code BLOB} * value from the array of bytes {@code bytes} * @return the number of bytes written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBytes * @since 1.4 */
int setBytes(long pos, byte[] bytes, int offset, int len) 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. 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 an SQLException while other drivers may support this operation.

Params:
  • pos – the position in the BLOB value at which to start writing; the first position is 1
Throws:
See Also:
Returns:a java.io.OutputStream object to which data can be written
Since:1.4
/** * Retrieves a stream that can be used to write to the {@code BLOB} * value that this {@code Blob} object represents. The stream begins * at position {@code pos}. * The bytes written to the stream will overwrite the existing bytes * in the {@code Blob} object starting at the position * {@code pos}. If the end of the {@code Blob} value is reached * while writing to the stream, then the length of the {@code Blob} * value will be increased to accommodate the extra bytes. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} value then the * behavior is undefined. Some JDBC drivers may throw an * {@code SQLException} while other drivers may support this * operation. * * @param pos the position in the {@code BLOB} value at which * to start writing; the first position is 1 * @return a {@code java.io.OutputStream} object to which data can * be written * @exception SQLException if there is an error accessing the * {@code BLOB} value or if pos is less than 1 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @see #getBinaryStream * @since 1.4 */
java.io.OutputStream setBinaryStream(long pos) throws 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 an SQLException while other drivers may support this operation.

Params:
  • len – the length, in bytes, to which the BLOB value that this Blob object represents should be truncated
Throws:
Since:1.4
/** * Truncates the {@code BLOB} value that this {@code Blob} * object represents to be {@code len} bytes in length. * <p> * <b>Note:</b> If the value specified for {@code pos} * is greater than the length+1 of the {@code BLOB} value then the * behavior is undefined. Some JDBC drivers may throw an * {@code SQLException} while other drivers may support this * operation. * * @param len the length, in bytes, to which the {@code BLOB} value * that this {@code Blob} object represents should be truncated * @exception SQLException if there is an error accessing the * {@code BLOB} value or if len is less than 0 * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.4 */
void truncate(long len) throws 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 an SQLException being thrown. If free is called multiple times, the subsequent calls to free are treated as a no-op.

Throws:
Since:1.6
/** * This method frees the {@code Blob} object and releases the resources that * it holds. The object is invalid once the {@code free} * method is called. * <p> * After {@code free} has been called, any attempt to invoke a * method other than {@code free} will result in an {@code SQLException} * being thrown. If {@code free} is called multiple times, the subsequent * calls to {@code free} are treated as a no-op. * * @throws SQLException if an error occurs releasing * the Blob's resources * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.6 */
void free() throws SQLException;
Returns an InputStream object that contains a partial Blob value, starting with the byte specified by pos, which is length bytes in length.
Params:
  • 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
Throws:
  • 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
  • SQLFeatureNotSupportedException – if the JDBC driver does not support this method
Returns:InputStream through which the partial Blob value can be read.
Since:1.6
/** * Returns an {@code InputStream} object that contains * a partial {@code Blob} value, starting with the byte * specified by pos, which is length bytes in length. * * @param pos the offset to the first byte of the partial value to be * retrieved. The first byte in the {@code Blob} is at position 1. * @param length the length in bytes of the partial value to be retrieved * @return {@code InputStream} through which * the partial {@code Blob} value can be read. * @throws SQLException if pos is less than 1 or if pos is greater * than the number of bytes in the {@code Blob} or if * pos + length is greater than the number of bytes * in the {@code Blob} * * @exception SQLFeatureNotSupportedException if the JDBC driver * does not support this method * @since 1.6 */
InputStream getBinaryStream(long pos, long length) throws SQLException; }