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package java.sql;

import java.io.InputStream;

/**
 * The representation (mapping) in
 * the Java™ programming
 * language of an SQL
 * <code>BLOB</code> value. An SQL <code>BLOB</code> 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</code> using
 * an SQL <code>locator(BLOB)</code>, which means that a
 * <code>Blob</code> object contains a logical pointer to the
 * SQL <code>BLOB</code> data rather than the data itself.
 * A <code>Blob</code> 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</code> and <code>setBlob</code> allow a programmer to
 * access an SQL <code>BLOB</code> value.
 * The <code>Blob</code> interface provides methods for getting the
 * length of an SQL <code>BLOB</code> (Binary Large Object) value,
 * for materializing a <code>BLOB</code> value on the client, and for
 * determining the position of a pattern of bytes within a
 * <code>BLOB</code> value. In addition, this interface has methods for updating
 * a <code>BLOB</code> value.
 * <p>
 * All methods on the <code>Blob</code> 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 <code>BLOB</code> value
 * designated by this <code>Blob</code> object.
 * @return length of the <code>BLOB</code> in bytes
 * @exception SQLException if there is an error accessing the
 * length of the <code>BLOB</code>
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.2
 */
 long length() throws SQLException;

 /**
 * Retrieves all or part of the <code>BLOB</code>
 * value that this <code>Blob</code> object represents, as an array of
 * bytes. This <code>byte</code> array contains up to <code>length</code>
 * consecutive bytes starting at position <code>pos</code>.
 *
 * @param pos the ordinal position of the first byte in the
 * <code>BLOB</code> 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</code>
 * consecutive bytes from the <code>BLOB</code> value designated
 * by this <code>Blob</code> object, starting with the
 * byte at position <code>pos</code>
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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 <code>BLOB</code> value designated by this
 * <code>Blob</code> instance as a stream.
 *
 * @return a stream containing the <code>BLOB</code> data
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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
 * <code>pattern</code> begins within the <code>BLOB</code>
 * value that this <code>Blob</code> object represents. The
 * search for <code>pattern</code> begins at position
 * <code>start</code>.
 *
 * @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</code> 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 <code>BLOB</code> value
 * designated by this <code>Blob</code> object at which
 * <code>pattern</code> begins. The search begins at position
 * <code>start</code>.
 *
 * @param pattern the <code>Blob</code> object designating
 * the <code>BLOB</code> value for which to search
 * @param start the position in the <code>BLOB</code> 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</code> 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 <code>BLOB</code> value that
 * this <code>Blob</code> object represents, starting at position
 * <code>pos</code>, and returns the number of bytes written.
 * The array of bytes will overwrite the existing bytes
 * in the <code>Blob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Blob</code> value is reached
 * while writing the array of bytes, then the length of the <code>Blob</code>
 * value will be increased to accommodate the extra bytes.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>BLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position in the <code>BLOB</code> object at which
 * to start writing; the first position is 1
 * @param bytes the array of bytes to be written to the <code>BLOB</code>
 * value that this <code>Blob</code> object represents
 * @return the number of bytes written
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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 <code>byte</code> array to the
 * <code>BLOB</code> value that this <code>Blob</code> object represents
 * and returns the number of bytes written.
 * Writing starts at position <code>pos</code> in the <code>BLOB</code>
 * value; <code>len</code> bytes from the given byte array are written.
 * The array of bytes will overwrite the existing bytes
 * in the <code>Blob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Blob</code> value is reached
 * while writing the array of bytes, then the length of the <code>Blob</code>
 * value will be increased to accommodate the extra bytes.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>BLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position in the <code>BLOB</code> object at which
 * to start writing; the first position is 1
 * @param bytes the array of bytes to be written to this <code>BLOB</code>
 * object
 * @param offset the offset into the array <code>bytes</code> at which
 * to start reading the bytes to be set
 * @param len the number of bytes to be written to the <code>BLOB</code>
 * value from the array of bytes <code>bytes</code>
 * @return the number of bytes written
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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 <code>BLOB</code>
 * value that this <code>Blob</code> object represents. The stream begins
 * at position <code>pos</code>.
 * The bytes written to the stream will overwrite the existing bytes
 * in the <code>Blob</code> object starting at the position
 * <code>pos</code>. If the end of the <code>Blob</code> value is reached
 * while writing to the stream, then the length of the <code>Blob</code>
 * value will be increased to accommodate the extra bytes.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>BLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param pos the position in the <code>BLOB</code> value at which
 * to start writing; the first position is 1
 * @return a <code>java.io.OutputStream</code> object to which data can
 * be written
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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 <code>BLOB</code> value that this <code>Blob</code>
 * object represents to be <code>len</code> bytes in length.
 * <p>
 * <b>Note:</b> If the value specified for <code>pos</code>
 * is greater then the length+1 of the <code>BLOB</code> value then the
 * behavior is undefined. Some JDBC drivers may throw a
 * <code>SQLException</code> while other drivers may support this
 * operation.
 *
 * @param len the length, in bytes, to which the <code>BLOB</code> value
 * that this <code>Blob</code> object represents should be truncated
 * @exception SQLException if there is an error accessing the
 * <code>BLOB</code> 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 <code>Blob</code> object and releases the resources that
 * it holds. The object is invalid once the <code>free</code>
 * method is called.
 *<p>
 * After <code>free</code> has been called, any attempt to invoke a
 * method other than <code>free</code> will result in a <code>SQLException</code>
 * being thrown. If <code>free</code> is called multiple times, the subsequent
 * calls to <code>free</code> are treated as a no-op.
 *<p>
 *
 * @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 <code>InputStream</code> object that contains a partial <code>Blob</code> 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</code> is at position 1
 * @param length the length in bytes of the partial value to be retrieved
 * @return <code>InputStream</code> through which the partial <code>Blob</code> 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</code> or if pos + length is greater than the number of bytes
 * in the <code>Blob</code>
 *
 * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
 * this method
 * @since 1.6
 */
 InputStream getBinaryStream(long pos, long length) throws SQLException;
}