+
−/*
+
− * 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 - 2020 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.mcl.io;
+
−
+
−import java.io.BufferedReader;
+
−import java.io.IOException;
+
−import java.io.InputStream;
+
−import java.io.Reader;
+
−import java.io.UnsupportedEncodingException;
+
−
+
−/**
+
− * Read text from a character-input stream, buffering characters so as
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− * to provide a means for efficient reading of characters, arrays and
+
− * lines.  This class is based on the BufferedReader class, and provides
+
− * extra functionality useful for MCL.
+
− *
+
− * The BufferedMCLReader is typically used as layer inbetween an
+
− * InputStream and a specific interpreter of the data.
+
− * <pre>
+
− *                         / Response
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− * BufferedMCLReader ---o &lt;- Tuple
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− *                         \ DataBlock
+
− * </pre>
+
− * Because the BufferedMCLReader provides an efficient way to access the
+
− * data from the stream in a linewise fashion, whereby each line is
+
− * identified as a certain type, consumers can easily decide how to
+
− * parse each retrieved line.  The line parsers from
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− * nl.cwi.monetdb.mcl.parser are well suited to work with the lines
+
− * outputted by the BufferedMCLReader.
+
− * This class is client-oriented, as it doesn't take into account the
+
− * messages as the server receives them.
+
− *
+
− * @author Fabian Groffen
+
− * @see nl.cwi.monetdb.mcl.net.MapiSocket
+
− * @see nl.cwi.monetdb.mcl.io.BufferedMCLWriter
+
− */
+
−public final class BufferedMCLReader extends BufferedReader {
+
−	/** "there is currently no line", or the the type is unknown is represented by UNKNOWN */
+
−	public final static int UNKNOWN  = 0;
+
−	/** a line starting with ! indicates ERROR */
+
−	public final static int ERROR    = '!';
+
−	/** a line starting with % indicates HEADER */
+
−	public final static int HEADER   = '%';
+
−	/** a line starting with [ indicates RESULT */
+
−	public final static int RESULT   = '[';
+
−	/** a line which matches the pattern of prompt1 is a PROMPT */
+
−	public final static int PROMPT   = '.';
+
−	/** a line which matches the pattern of prompt2 is a MORE */
+
−	public final static int MORE     = ',';
+
−	/** a line starting with &amp; indicates the start of a header block */
+
−	public final static int SOHEADER = '&';
+
−	/** a line starting with ^ indicates REDIRECT */
+
−	public final static int REDIRECT = '^';
+
−	/** a line starting with # indicates INFO */
+
−	public final static int INFO     = '#';
+
−
+
−	/** The type of the last line read */
+
−	private int lineType = UNKNOWN;
+
−
+
−	/**
+
−	 * Create a buffering character-input stream that uses a
+
−	 * default-sized input buffer.
+
−	 *
+
−	 * @param in A Reader
+
−	 */
+
−	public BufferedMCLReader(final Reader in) {
+
−		super(in);
+
−	}
+
−
+
−	/**
+
−	 * Create a buffering character-input stream that uses a
+
−	 * default-sized input buffer, from an InputStream.
+
−	 *
+
−	 * @param in An InputStream
+
−	 * @param enc Encoding
+
−	 * @throws UnsupportedEncodingException If encoding is not supported
+
−	 */
+
−	public BufferedMCLReader(final InputStream in, final String enc)
+
−		throws UnsupportedEncodingException
+
−	{
+
−		super(new java.io.InputStreamReader(in, enc));
+
−	}
+
−
+
−	/**
+
−	 * Read a line of text.  A line is considered to be terminated by
+
−	 * any one of a line feed ('\n'), a carriage return ('\r'), or a
+
−	 * carriage return followed immediately by a linefeed.  Before this
+
−	 * method returns, it sets the linetype to any of the in MCL
+
−	 * recognised line types.
+
−	 *
+
−	 * Warning: until the server properly prefixes all of its error
+
−	 * messages with SQLSTATE codes, this method prefixes all errors it
+
−	 * sees without sqlstate with the generic data exception code (22000).
+
−	 *
+
−	 * @return A String containing the contents of the line, not
+
−	 *         including any line-termination characters, or null if the
+
−	 *         end of the stream has been reached
+
−	 * @throws IOException If an I/O error occurs
+
−	 */
+
−	@Override
+
−	public String readLine() throws IOException {
+
−		String r = super.readLine();
+
−		setLineType(r);
+
−		if (lineType == ERROR && r != null && !r.matches("^![0-9A-Z]{5}!.+")) {
+
−			r = "!22000!" + r.substring(1);
+
−		}
+
−		return r;
+
−	}
+
−	
+
−	/**
+
−	 * Sets the linetype to the type of the string given.  If the string
+
−	 * is null, lineType is set to UNKNOWN.
+
−	 *
+
−	 * @param line the string to examine
+
−	 */
+
−	public void setLineType(final String line) {
+
−		if (line == null || line.isEmpty()) {
+
−			lineType = UNKNOWN;
+
−			return;
+
−		}
+
−		switch (line.charAt(0)) {
+
−			case '.':
+
−				lineType = PROMPT;
+
−				break;
+
−			case ',':
+
−				lineType = MORE;
+
−				break;
+
−			case '[':	/* multi field result */
+
−			case '=':	/* single value result */
+
−				lineType = RESULT;
+
−				break;
+
−			case '%':
+
−				lineType = HEADER;
+
−				break;
+
−			case '&':
+
−				lineType = SOHEADER;
+
−				break;
+
−			case '#':
+
−				lineType = INFO;
+
−				break;
+
−			case '!':
+
−				lineType = ERROR;
+
−				break;
+
−			case '^':
+
−				lineType = REDIRECT;
+
−				break;
+
−			default:
+
−				lineType = UNKNOWN;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * getLineType returns the type of the last line read.
+
−	 *
+
−	 * @return an integer representing the kind of line this is, one of the
+
−	 *         following constants: UNKNOWN, HEADER, ERROR, PROMPT, MORE,
+
−	 *         RESULT, SOHEADER, REDIRECT, INFO
+
−	 */
+
−	public int getLineType() {
+
−		return lineType;
+
−	}
+
−
+
−	/**
+
−	 * Reads up till the MonetDB prompt, indicating the server is ready
+
−	 * for a new command.  All read data is discarded.  If the last line
+
−	 * read by readLine() was a prompt, this method will immediately return.
+
−	 *
+
−	 * If there are errors present in the lines that are read, then they
+
−	 * are put in one string and returned <b>after</b> the prompt has
+
−	 * been found. If no errors are present, null will be returned.
+
−	 *
+
−	 * @return a string containing error messages, or null if there aren't any
+
−	 * @throws IOException if an IO exception occurs while talking to the server
+
−	 *
+
−	 * TODO(Wouter): should probably not have to be synchronized.
+
−	 */
+
−	final public synchronized String waitForPrompt() throws IOException {
+
−		final StringBuilder ret = new StringBuilder(128);
+
−		String tmp;
+
−
+
−		while (lineType != PROMPT) {
+
−			tmp = readLine();
+
−			if (tmp == null)
+
−				throw new IOException("Connection to server lost!");
+
−			if (lineType == ERROR)
+
−				ret.append('\n').append(tmp.substring(1));
+
−		}
+
−		return ret.length() == 0 ? null : ret.toString().trim();
+
−	}
+
−}