+
−/*
+
− * 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 - 2017 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.jdbc;
+
−
+
−import java.io.InputStream;
+
−import java.io.OutputStream;
+
−import java.io.Reader;
+
−import java.io.StringReader;
+
−import java.io.Writer;
+
−import java.sql.Clob;
+
−import java.sql.SQLException;
+
−import java.sql.SQLFeatureNotSupportedException;
+
−
+
−/**
+
− * The MonetClob class implements the {@link java.sql.Clob} interface.  Because
+
− * MonetDB/SQL currently has no support for streams, this class is a
+
− * shallow wrapper of a {@link StringBuilder}.  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
+
− * sole reason for a Clob: avoidance of huge resource consumption.
+
− * <b>Use of this class is highly discouraged.</b>
+
− *
+
− * @author Fabian Groffen
+
− */
+
−public class MonetClob implements Clob {
+
−
+
−	private StringBuilder buf;
+
−
+
−	protected MonetClob(String in) {
+
−		buf = new StringBuilder(in);
+
−	}
+
−
+
−	/* internal utility method */
+
−	private void checkBufIsNotNull() throws SQLException {
+
−		if (buf == null)
+
−			throw new SQLException("This MonetClob has been freed", "M1M20");
+
−	}
+
−
+
−	//== begin interface Clob
+
−
+
−	/**
+
−	 * This method frees the Clob object and releases the resources 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.
+
−	 */
+
−	@Override
+
−	public void free() {
+
−		buf = null;
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the CLOB value designated by this Clob object as an
+
−	 * ascii stream.
+
−	 *
+
−	 * @return a java.io.InputStream object containing the CLOB data
+
−	 * @throws SQLFeatureNotSupportedException this JDBC driver does
+
−	 *         not support this method
+
−	 */
+
−	@Override
+
−	public InputStream getAsciiStream() throws SQLException {
+
−		throw new SQLFeatureNotSupportedException("Method getAsciiStream() not supported", "0A000");
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the CLOB value designated by this Clob object as a
+
−	 * java.io.Reader object (or as a stream of characters).
+
−	 *
+
−	 * @return a java.io.Reader object containing the CLOB data
+
−	 * @throws SQLFeatureNotSupportedException this JDBC driver does
+
−	 *         not support this method
+
−	 */
+
−	@Override
+
−	public Reader getCharacterStream() throws SQLException {
+
−		checkBufIsNotNull();
+
−		return new StringReader(buf.toString());
+
−	}
+
−
+
−	/**
+
−	 * Returns a Reader object that contains a partial Clob value,
+
−	 * starting with the character specified by pos, which is length
+
−	 * characters in length.
+
−	 *
+
−	 * @param pos the offset to the first character of the partial value
+
−	 *        to be retrieved. The first character in the Clob is at
+
−	 *        position 1.
+
−	 * @param length the length in characters of the partial value to be
+
−	 *        retrieved.
+
−	 * @return Reader through which the partial Clob value can be read.
+
−	 * @throws SQLFeatureNotSupportedException this JDBC driver does
+
−	 *         not support this method
+
−	 */
+
−	@Override
+
−	public Reader getCharacterStream(long pos, long length) throws SQLException {
+
−		checkBufIsNotNull();
+
−		return new StringReader(getSubString(pos, (int)length));
+
−	}
+
−
+
−	/**
+
−	 * Retrieves a copy of the specified substring in the CLOB value
+
−	 * designated by this Clob object.  The substring begins at
+
−	 * position pos and has up to length consecutive characters.
+
−	 *
+
−	 * @param pos the first character of the substring to be
+
−	 *        extracted. The first character is at position 1.
+
−	 * @param length the number of consecutive characters to be copied
+
−	 * @return a String that is the specified substring in the
+
−	 *         CLOB value designated by this Clob object
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public String getSubString(long pos, int length) throws SQLException {
+
−		checkBufIsNotNull();
+
−		try {
+
−			return buf.substring((int)(pos - 1), (int)(pos - 1 + length));
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw new SQLException(e.getMessage());
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the number of characters in the CLOB value designated
+
−	 * by this Clob object.
+
−	 *
+
−	 * @return length of the CLOB in characters
+
−	 * @throws SQLException if there is an error accessing the length
+
−	 *         of the CLOB value
+
−	 */
+
−	@Override
+
−	public long length() throws SQLException {
+
−		checkBufIsNotNull();
+
−		return (long)buf.length();
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the character position at which the specified Clob
+
−	 * object searchstr appears in this Clob object.  The search
+
−	 * begins at position start.
+
−	 *
+
−	 * @param searchstr the Clob object for which to search
+
−	 * @param start the position at which to begin searching;
+
−	 *        the first position is 1
+
−	 * @return the position at which the Clob object appears or
+
−	 *         -1 if it is not present; the first position is 1
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public long position(Clob searchstr, long start) throws SQLException {
+
−		return position(searchstr.getSubString(1L, (int)(searchstr.length())), start);
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the character position at which the specified
+
−	 * substring searchstr appears in the SQL CLOB value represented
+
−	 * by this Clob object.  The search begins at position start.
+
−	 *
+
−	 * @param searchstr the substring for which to search
+
−	 * @param start the position at which to begin searching;
+
−	 *        the first position is 1
+
−	 * @return the position at which the substring appears or
+
−	 *         -1 if it is not present; the first position is 1
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public long position(String searchstr, long start) throws SQLException {
+
−		checkBufIsNotNull();
+
−		return (long)(buf.indexOf(searchstr, (int)(start - 1)));
+
−	}
+
−
+
−	@Override
+
−	public OutputStream setAsciiStream(long pos) throws SQLException {
+
−		throw new SQLFeatureNotSupportedException("Method setAsciiStream(long pos) not supported", "0A000");
+
−	}
+
−
+
−	@Override
+
−	public Writer setCharacterStream(long pos) throws SQLException {
+
−		throw new SQLFeatureNotSupportedException("Method setCharacterStream(long pos) not supported", "0A000");
+
−	}
+
−
+
−	/**
+
−	 * Writes the given Java String to the CLOB  value that this
+
−	 * Clob object designates at the position pos.
+
−	 *
+
−	 * @param pos the position at which to start writing to the
+
−	 *        CLOB value that this Clob object represents
+
−	 * @param str the string to be written to the CLOB value that
+
−	 *        this Clob designates
+
−	 * @return the number of characters written
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public int setString(long pos, String str) throws SQLException {
+
−		return setString(pos, str, 1, str.length());
+
−	}
+
−
+
−	/**
+
−	 * Writes len characters of str, starting at character offset,
+
−	 * to the CLOB value that this Clob represents.
+
−	 *
+
−	 * @param pos the position at which to start writing to this
+
−	 *        CLOB object
+
−	 * @param str the string to be written to the CLOB value that
+
−	 *        this Clob object represents
+
−	 * @param offset the offset into str to start reading the
+
−	 *        characters to be written
+
−	 * @param len the number of characters to be written
+
−	 * @return the number of characters written
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public int setString(long pos, String str, int offset, int len)
+
−		throws SQLException
+
−	{
+
−		checkBufIsNotNull();
+
−
+
−		int buflen = buf.length();
+
−		int retlen = Math.min(buflen, (int)(pos - 1 + len));
+
−		if (retlen > 0) {
+
−			buf.replace((int)(pos - 1), (int)(pos + retlen), str.substring(offset - 1, (offset + len)));
+
−			return retlen;
+
−		} else {
+
−			return 0;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Truncates the CLOB value that this Clob designates to
+
−	 * have a length of len characters.
+
−	 *
+
−	 * @param len the length, in bytes, to which the CLOB value
+
−	 *        should be truncated
+
−	 * @throws SQLException if there is an error accessing the
+
−	 *         CLOB value
+
−	 */
+
−	@Override
+
−	public void truncate(long len) throws SQLException {
+
−		checkBufIsNotNull();
+
−		// this command is a no-op
+
−	}
+
−
+
−	/**
+
−	 * Returns the String behind this Clob.  This is a MonetClob
+
−	 * extension that does not violate nor is described in the Clob
+
−	 * interface.
+
−	 *
+
−	 * @return the String this Clob wraps.
+
−	 */
+
−	@Override
+
−	public String toString() {
+
−		return (buf == null) ? "null" : buf.toString();
+
−	}
+
−}