+
−/*
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 1997 - July 2008 CWI, August 2008 - 2019 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.jdbc;
+
−
+
−import java.io.ByteArrayInputStream;
+
−import java.io.InputStream;
+
−import java.io.OutputStream;
+
−import java.sql.Blob;
+
−import java.sql.SQLException;
+
−import java.sql.SQLFeatureNotSupportedException;
+
−
+
−/**
+
− * The MonetBlob class implements the {@link java.sql.Blob} interface.
+
− *
+
− * Because MonetDB/SQL currently has no support for streams, this class is a
+
− * shallow wrapper of a byte[].  It is more or less supplied to
+
− * enable an application that depends on it to run.  It may be obvious
+
− * that it is a real resource expensive workaround that contradicts the
+
− * benefits for a Blob: avoidance of huge resource consumption.
+
− * <b>Use of this class is highly discouraged.</b>
+
− *
+
− * @author Fabian Groffen
+
− */
+
−public final class MonetBlob implements Blob {
+
−	private byte[] buf;
+
−
+
−	protected MonetBlob(byte[] data) {
+
−		buf = data;
+
−	}
+
−	
+
−	static MonetBlob create(String in) {
+
−		// unpack the HEX (BLOB) notation to real bytes
+
−		int len = in.length() / 2;
+
−		byte[] buf = new byte[len];
+
−		int offset;
+
−		for (int i = 0; i < len; i++) {
+
−			offset = 2 * i;
+
−			buf[i] = (byte)Integer.parseInt(in.substring(offset, offset + 2), 16);
+
−		}
+
−		return new MonetBlob(buf);
+
−	}
+
−
+
−	/* internal utility method */
+
−	final private void checkBufIsNotNull() throws SQLException {
+
−		if (buf == null)
+
−			throw new SQLException("This MonetBlob has been freed", "M1M20");
+
−	}
+
−
+
−	//== begin interface Blob
+
−	
+
−	/**
+
−	 * 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
+
−	 */
+
−	@Override
+
−	public void free() throws SQLException {
+
−		buf = null;
+
−	}
+
−	
+
−	/**
+
−	 * Retrieves the BLOB value designated by this Blob instance as a
+
−	 * stream.
+
−	 *
+
−	 * @return a stream containing the BLOB data
+
−	 * @throws SQLException if there is an error accessing the BLOB value
+
−	 */
+
−	@Override
+
−	public InputStream getBinaryStream() throws SQLException {
+
−		checkBufIsNotNull();
+
−		return new ByteArrayInputStream(buf);
+
−	}
+
−
+
−	/**
+
−	 * Returns an InputStream object that contains a partial 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 Blob is at position 1
+
−	 * @param length the length in bytes of the partial value to be
+
−	 *        retrieved
+
−	 * @return InputStream through which the partial 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 Blob or if pos +
+
−	 *         length is greater than the number of bytes in the Blob
+
−	 */
+
−	@Override
+
−	public InputStream getBinaryStream(long pos, long length)
+
−		throws SQLException
+
−	{
+
−		checkBufIsNotNull();
+
−		if (pos < 1 || pos > buf.length) {
+
−			throw new SQLException("Invalid pos value: " + pos, "M1M05");
+
−		}
+
−		if (length < 0 || pos - 1 + length > buf.length) {
+
−			throw new SQLException("Invalid length value: " + length, "M1M05");
+
−		}
+
−
+
−		return new ByteArrayInputStream(buf, (int) pos - 1, (int) length);
+
−	}
+
−
+
−	/**
+
−	 * 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.
+
−	 *
+
−	 * @param pos the ordinal position of the first byte in the BLOB
+
−	 *        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 length consecutive bytes
+
−	 *         from the BLOB value designated by this Blob object,
+
−	 *         starting with the byte at position pos.
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         BLOB value
+
−	 */
+
−	@Override
+
−	public byte[] getBytes(long pos, int length) throws SQLException {
+
−		checkBufIsNotNull();
+
−		if (pos < 1 || pos > buf.length) {
+
−			throw new SQLException("Invalid pos value: " + pos, "M1M05");
+
−		}
+
−		if (length < 0 || pos - 1 + length > buf.length) {
+
−			throw new SQLException("Invalid length value: " + length, "M1M05");
+
−		}
+
−
+
−		try {
+
−			return java.util.Arrays.copyOfRange(buf, (int) pos - 1, (int) pos - 1 + length);
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw new SQLException(e.getMessage(), "M0M10");
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Returns the number of bytes in the BLOB value designated by this
+
−	 * Blob object.
+
−	 *
+
−	 * @return length of the BLOB in bytes
+
−	 * @throws SQLException if there is an error accessing the length
+
−	 *         of the BLOB value
+
−	 */
+
−	@Override
+
−	public long length() throws SQLException {
+
−		checkBufIsNotNull();
+
−		return (long)buf.length;
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the byte position in the BLOB value designated by this
+
−	 * Blob object at which pattern begins.  The search begins at
+
−	 * position start.
+
−	 *
+
−	 * @param pattern the Blob object designating the BLOB value for
+
−	 *        which to search
+
−	 * @param start the position in the BLOB 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
+
−	 *         BLOB value
+
−	 */
+
−	@Override
+
−	public long position(Blob pattern, long start) throws SQLException {
+
−		if (pattern == null) {
+
−			throw new SQLException("Missing pattern object", "M1M05");
+
−		}
+
−		return position(pattern.getBytes(1L, (int)pattern.length()), start);
+
−	}
+
−
+
−	/**
+
−	 * 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.
+
−	 *
+
−	 * @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
+
−	 *         BLOB value
+
−	 */
+
−	@Override
+
−	public long position(byte[] pattern, long start) throws SQLException {
+
−		checkBufIsNotNull();
+
−		if (pattern == null) {
+
−			throw new SQLException("Missing pattern object", "M1M05");
+
−		}
+
−		if (start < 1 || start > buf.length) {
+
−			throw new SQLException("Invalid start value: " + start, "M1M05");
+
−		}
+
−		try {
+
−			final int patternLength = pattern.length;
+
−			final int bufLength = buf.length;
+
−			for (int i = (int)(start - 1); i < bufLength - patternLength; i++) {
+
−				int j;
+
−				for (j = 0; j < patternLength; j++) {
+
−					if (buf[i + j] != pattern[j])
+
−						break;
+
−				}
+
−				if (j == patternLength)
+
−					return i;
+
−			}
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw new SQLException(e.getMessage(), "M0M10");
+
−		}
+
−		return -1;
+
−	}
+
−
+
−	/**
+
−	 * 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 accomodate the
+
−	 * extra bytes.
+
−	 *
+
−	 * @param pos the position in the BLOB value at which to start
+
−	 *            writing; the first position is 1
+
−	 * @return a java.io.OutputStream object to which data can be
+
−	 *         written
+
−	 * @throws SQLException if there is an error accessing the BLOB
+
−	 *         value or if pos is less than 1
+
−	 * @throws SQLFeatureNotSupportedException if the JDBC driver does
+
−	 *         not support this method
+
−	 */
+
−	@Override
+
−	public OutputStream setBinaryStream(long pos) throws SQLException {
+
−		throw new SQLFeatureNotSupportedException("Method setBinaryStream(long pos) not supported", "0A000");
+
−	}
+
−
+
−	/**
+
−	 * 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.
+
−	 *
+
−	 * @param pos the position in the BLOB object at which to start
+
−	 *        writing
+
−	 * @param bytes the array of bytes to be written to the BLOB  value
+
−	 *        that this Blob object represents
+
−	 * @return the number of bytes written
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         BLOB value or if pos is less than 1
+
−	 */
+
−	@Override
+
−	public int setBytes(long pos, byte[] bytes) throws SQLException {
+
−		if (bytes == null) {
+
−			throw new SQLException("Missing bytes[] object", "M1M05");
+
−		}
+
−		return setBytes(pos, bytes, 1, 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.  Writing starts at position pos in the BLOB  value; len
+
−	 * bytes from the given byte array are written.
+
−	 *
+
−	 * @param pos the position in the BLOB object at which to start
+
−	 *        writing
+
−	 * @param bytes the array of bytes to be written to this BLOB
+
−	 *        object
+
−	 * @param offset the offset into the array bytes at which to start
+
−	 *        reading the bytes to be set
+
−	 * @param len the number of bytes to be written to the BLOB  value
+
−	 *        from the array of bytes bytes
+
−	 * @return the number of bytes written
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         BLOB value or if pos is less than 1
+
−	 */
+
−	@Override
+
−	public int setBytes(long pos, byte[] bytes, int offset, int len)
+
−		throws SQLException
+
−	{
+
−		checkBufIsNotNull();
+
−		if (bytes == null) {
+
−			throw new SQLException("Missing bytes[] object", "M1M05");
+
−		}
+
−		if (pos < 1 || pos > Integer.MAX_VALUE) {
+
−			throw new SQLException("Invalid pos value: " + pos, "M1M05");
+
−		}
+
−		if (len < 0 || pos + len > buf.length) {
+
−			throw new SQLException("Invalid len value: " + len, "M1M05");
+
−		}
+
−		if (offset < 0 || offset > bytes.length) {
+
−			throw new SQLException("Invalid offset value: " + offset, "M1M05");
+
−		}
+
−
+
−		try {
+
−			/* transactions? what are you talking about? */
+
−			for (int i = (int)pos; i < len; i++)
+
−				buf[i] = bytes[offset - 1 + i];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw new SQLException(e.getMessage(), "M0M10");
+
−		}
+
−		return len;
+
−	}
+
−
+
−	/**
+
−	 * Truncates the BLOB value that this Blob  object represents to be
+
−	 * len bytes in length.
+
−	 *
+
−	 * @param len the length, in bytes, to which the BLOB value
+
−	 *        should be truncated
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         BLOB value
+
−	 */
+
−	@Override
+
−	public void truncate(long len) throws SQLException {
+
−		checkBufIsNotNull();
+
−		if (len < 0 || len > buf.length) {
+
−			throw new SQLException("Invalid len value: " + len, "M1M05");
+
−		}
+
−		if (buf.length > len) {
+
−			byte[] newbuf = new byte[(int)len];
+
−			for (int i = 0; i < len; i++)
+
−				newbuf[i] = buf[i];
+
−			buf = newbuf;
+
−		}
+
−	}
+
−}