http://hsqldb.org: HSQLDB - Lightweight 100% Java SQL Database Engine (The HSQL Development Group)
  • Blaine Simpson 
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 *
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package org.hsqldb.jdbc;

import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.SQLException;

import org.hsqldb.HsqlException;
import org.hsqldb.SessionInterface;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.types.BlobDataID;
import org.hsqldb.types.BlobInputStream;


A wrapper for HSQLDB BlobData objects.
Instances of this class are returned by calls to ResultSet methods.

Author:Fred Toussi (fredt@users dot sourceforge.net)
Version:2.3.5
Since:1.9.0
/**
 * A wrapper for HSQLDB BlobData objects.
 *
 * Instances of this class are returned by calls to ResultSet methods.
 *
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.5
 * @since 1.9.0
 */
public class JDBCBlobClient implements Blob {

    
Returns the number of bytes in the BLOB value designated
by this Blob object.

Throws:
  • SQLException – if there is an error accessing the length of the
  BLOB
Returns:length of the BLOB in bytes
/**
     * 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
     * @throws SQLException if there is an error accessing the length of the
     *   <code>BLOB</code>
     */
    public synchronized long length() throws SQLException {

        checkClosed();

        try {
            return blob.length(session);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    
Retrieves all or part of the BLOB value that this
Blob object represents, as an array of bytes.

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
Throws:
  • SQLException – if there is an error accessing the
  BLOB value
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
/**
     * Retrieves all or part of the <code>BLOB</code> value that this
     * <code>Blob</code> object represents, as an array of bytes.
     *
     * @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
     * @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>
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized byte[] getBytes(long pos,
                                        int length) throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, pos - 1, length)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            return blob.getBytes(session, pos - 1, length);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    
Retrieves the BLOB value designated by this
Blob instance as a stream.

Throws:
  • SQLException – if there is an error accessing the
  BLOB value
Returns:a stream containing the BLOB data
/**
     * 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
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized InputStream getBinaryStream() throws SQLException {

        checkClosed();

        return new BlobInputStream(session, blob, 0, length());
    }

    
Retrieves the byte position at which the specified byte array
pattern begins within the BLOB value that
this Blob object represents.

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
/**
     * 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.
     *
     * @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
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code>
     */
    public synchronized long position(byte[] pattern,
                                      long start) throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, start - 1, 0)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            long position = blob.position(session, pattern, start - 1);

            if (position >= 0) {
                position++;
            }

            return position;
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    
Retrieves the byte position in the BLOB value designated
by this Blob object at which pattern begins.

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:
  • SQLException – if there is an error accessing the
  BLOB value
Returns:the position at which the pattern begins, else -1
/**
     * Retrieves the byte position in the <code>BLOB</code> value designated
     * by this <code>Blob</code> object at which <code>pattern</code> begins.
     *
     * @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
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized long position(Blob pattern,
                                      long start) throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, start - 1, 0)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (pattern instanceof JDBCBlobClient) {
            BlobDataID searchClob = ((JDBCBlobClient) pattern).blob;

            try {
                long position = blob.position(session, searchClob, start - 1);

                if (position >= 0) {
                    position++;
                }

                return position;
            } catch (HsqlException e) {
                throw JDBCUtil.sqlException(e);
            }
        }

        if (!isInLimits(Integer.MAX_VALUE, 0, pattern.length())) {
            throw JDBCUtil.outOfRangeArgument();
        }

        byte[] bytePattern = pattern.getBytes(1, (int) pattern.length());

        return position(bytePattern, start);
    }

    
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.

Params:
  • pos – the position in the BLOB object at which to
  start writing
  • bytes – the array of bytes to be written to the
  BLOB value that this Blob object
  represents
Throws:
  • SQLException – if there is an error accessing the
  BLOB value
Returns:the number of bytes written
/**
     * 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.
     *
     * @param pos the position in the <code>BLOB</code> object at which to
     *   start writing
     * @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
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized int setBytes(long pos,
                                     byte[] bytes) throws SQLException {
        return setBytes(pos, bytes, 0, bytes.length);
    }

    
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.

Params:
  • pos – the position in the BLOB object at which to
  start writing
  • 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:
  • SQLException – if there is an error accessing the
  BLOB value
Returns:the number of bytes written
/**
     * 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.
     *
     * @param pos the position in the <code>BLOB</code> object at which to
     *   start writing
     * @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
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized int setBytes(long pos, byte[] bytes, int offset,
                                     int len) throws SQLException {

        checkClosed();

        if (!isInLimits(bytes.length, offset, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (!isInLimits(Long.MAX_VALUE, pos - 1, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (!isWritable) {
            throw JDBCUtil.notUpdatableColumn();
        }

        startUpdate();

        try {
            blob.setBytes(session, pos - 1, bytes, offset, len);

            return len;
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    
Retrieves a stream that can be used to write to the BLOB
value that this Blob object represents.

Params:
  • pos – the position in the BLOB value at which to
  start writing
Throws:
  • SQLException – if there is an error accessing the
  BLOB value
Returns:a java.io.OutputStream object to which data can
  be written
/**
     * Retrieves a stream that can be used to write to the <code>BLOB</code>
     * value that this <code>Blob</code> object represents.
     *
     * @param pos the position in the <code>BLOB</code> value at which to
     *   start writing
     * @return a <code>java.io.OutputStream</code> object to which data can
     *   be written
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized OutputStream setBinaryStream(long pos)
    throws SQLException {
        throw JDBCUtil.notSupported();
    }

    
Truncates the BLOB value that this Blob
object represents to be len bytes in length.

Params:
  • len – the length, in bytes, to which the BLOB value
  that this Blob object represents should be truncated
Throws:
  • SQLException – if there is an error accessing the
  BLOB value
/**
     * Truncates the <code>BLOB</code> value that this <code>Blob</code>
     * object represents to be <code>len</code> bytes in length.
     *
     * @param len the length, in bytes, to which the <code>BLOB</code> value
     *   that this <code>Blob</code> object represents should be truncated
     * @throws SQLException if there is an error accessing the
     *   <code>BLOB</code> value
     */
    public synchronized void truncate(long len) throws SQLException {

        checkClosed();

        if (!isInLimits(Long.MAX_VALUE, 0, len)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        try {
            blob.truncate(session, len);
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }
    }

    
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.



Throws:
  • SQLException – if an error occurs releasing
the Blob's resources
Since:JDK 1.6, HSQLDB 2.0
/**
     * 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
     * @since JDK 1.6, HSQLDB 2.0
     */
    public synchronized void free() throws SQLException {
        isClosed = true;
    }

    
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
Returns:InputStream through which the partial Blob value can be read.
Since:JDK 1.6, HSQLDB 2.0
/**
     * 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>
     *
     * @since JDK 1.6, HSQLDB 2.0
     */
    public synchronized InputStream getBinaryStream(long pos,
            long length) throws SQLException {

        checkClosed();

        if (!isInLimits(this.length(), pos - 1, length)) {
            throw JDBCUtil.outOfRangeArgument();
        }

        return new BlobInputStream(session, blob, pos - 1, length);
    }

    //--
    BlobDataID       originalBlob;
    BlobDataID       blob;
    SessionInterface session;
    int              colIndex;
    private boolean  isClosed;
    private boolean  isWritable;
    JDBCResultSet    resultSet;

    public JDBCBlobClient(SessionInterface session, BlobDataID blob) {
        this.session = session;
        this.blob    = blob;
    }

    public boolean isClosed() {
        return isClosed;
    }

    public BlobDataID getBlob() {
        return blob;
    }

    public synchronized void setWritable(JDBCResultSet result, int index) {

        isWritable = true;
        resultSet  = result;
        colIndex   = index;
    }

    public synchronized void clearUpdates() {

        if (originalBlob != null) {
            blob         = originalBlob;
            originalBlob = null;
        }
    }

    private void startUpdate() throws SQLException {

        if (originalBlob != null) {
            return;
        }

        originalBlob = blob;
        blob         = (BlobDataID) blob.duplicate(session);

        resultSet.startUpdate(colIndex + 1);

        resultSet.preparedStatement.parameterValues[colIndex] = blob;
        resultSet.preparedStatement.parameterSet[colIndex]    = Boolean.TRUE;
    }

    private void checkClosed() throws SQLException {

        if (isClosed) {
            throw JDBCUtil.sqlException(ErrorCode.X_0F502);
        }
    }

    static boolean isInLimits(long fullLength, long pos, long len) {
        return pos >= 0 && len >= 0 && pos + len <= fullLength;
    }
}