+
−/*
+
− * 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
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− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
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− * Copyright 1997 - July 2008 CWI, August 2008 - 2022 MonetDB B.V.
+
− */
+
−
+
−package org.monetdb.mcl.io;
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−
+
−import java.io.BufferedReader;
+
−import java.io.IOException;
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−import java.io.InputStream;
+
−import java.io.Reader;
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−import java.io.UnsupportedEncodingException;
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−
+
−/**
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− * Read text from a character-input stream, buffering characters so as to
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− * provide a means for efficient reading of characters, arrays and lines.
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− *
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− * The BufferedMCLReader is typically used as layer inbetween an
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− * InputStream and a specific interpreter of the data.
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− * <pre>
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− *                         / Response
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− * BufferedMCLReader ---o &lt;- Tuple
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− *                         \ DataBlock
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− * </pre>
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− * Because the BufferedMCLReader provides an efficient way to access the
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− * data from the stream in a linewise fashion, whereby each line is
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− * identified as a certain type, consumers can easily decide how to
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− * parse each retrieved line.  The line parsers from
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− * org.monetdb.mcl.parser are well suited to work with the lines
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− * outputted by the BufferedMCLReader.
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− * This class is client-oriented, as it doesn't take into account the
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− * messages as the server receives them.
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− *
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− * @author Fabian Groffen
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− * @see org.monetdb.mcl.net.MapiSocket
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− * @see org.monetdb.mcl.io.BufferedMCLWriter
+
− */
+
−public final class BufferedMCLReader {
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−
+
−	private final BufferedReader inner;
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−	private String current = null;
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−	private LineType lineType = LineType.UNKNOWN;
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−
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−	/**
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−	 * Create a buffering character-input stream that uses a
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−	 * default-sized input buffer.
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−	 *
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−	 * @param in A Reader
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−	 */
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−	public BufferedMCLReader(final Reader in) {
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−		inner = new BufferedReader(in);
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−	}
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−
+
−	/**
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−	 * Create a buffering character-input stream that uses a
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−	 * default-sized input buffer, from an InputStream.
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−	 *
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−	 * @param in An InputStream
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−	 * @param enc Encoding
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−	 * @throws UnsupportedEncodingException If encoding is not supported
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−	 */
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−	public BufferedMCLReader(final InputStream in, final String enc)
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−		throws UnsupportedEncodingException
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−	{
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−		this(new java.io.InputStreamReader(in, enc));
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−	}
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−
+
−	public void advance() throws IOException {
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−		if (lineType == LineType.PROMPT)
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−			return;
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−
+
−		current = inner.readLine();
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−		lineType = LineType.classify(current);
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−		if (lineType == LineType.ERROR && current != null && !current.matches("^![0-9A-Z]{5}!.+")) {
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−			current = "!22000!" + current.substring(1);
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−		}
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−	}
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−
+
−	/**
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−	 * Resets the linetype to UNKNOWN.
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−	 */
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−	public void resetLineType() {
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−		lineType = LineType.UNKNOWN;
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−	}
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−
+
−	/**
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−	 * Return the current line, or null if we're at the end or before the beginning.
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−	 * @return the current line or null
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−	 */
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−	public String getLine() {
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−		return current;
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−	}
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−
+
−	/**
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−	 * getLineType returns the type of the current line.
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−	 *
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−	 * @return Linetype representing the kind of line this is, one of the
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−	 *         following enums: UNKNOWN, HEADER, ERROR, RESULT,
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−	 *         PROMPT, MORE, FILETRANSFER, SOHEADER, REDIRECT, INFO
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−	 */
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−	public LineType getLineType() {
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−		return lineType;
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−	}
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−
+
−	/**
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−	 * Discard the remainder of the response but collect any further error messages.
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−	 *
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−	 * @return a string containing error messages, or null if there aren't any
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−	 * @throws IOException if an IO exception occurs while talking to the server
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−	 */
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−	final public String discardRemainder() throws IOException {
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−		return discard(null);
+
−	}
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−
+
−	/**
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−	 * Discard the remainder of the response but collect any further error messages.
+
−	 *
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−	 * @return a string containing error messages, or null if there aren't any
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−	 * @throws IOException if an IO exception occurs while talking to the server
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−	 */
+
−	final public String discardRemainder(String error) throws IOException {
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−		final StringBuilder sb;
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−
+
−		if (error != null) {
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−			sb = makeErrorBuffer();
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−			sb.append(error);
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−		} else {
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−			sb = null;
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−		}
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−		return discard(sb);
+
−	}
+
−
+
−	/**
+
−	 * Discard the remainder of the response but collect any further error messages.
+
−	 *
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−	 * @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
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−	 *
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−	 * TODO(Wouter): should probably not have to be synchronized.
+
−	 */
+
−	final synchronized String discard(StringBuilder errmsgs) throws IOException {
+
−		while (lineType != LineType.PROMPT) {
+
−			advance();
+
−			if (getLine() == null)
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−				throw new IOException("Connection to server lost!");
+
−			if (getLineType() == LineType.ERROR) {
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−				if (errmsgs == null)
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−					errmsgs = new StringBuilder(128);
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−				errmsgs.append('\n').append(getLine().substring(1));
+
−			}
+
−		}
+
−		if (errmsgs == null)
+
−			return null;
+
−		return errmsgs.toString().trim();
+
−	}
+
−
+
−	private final StringBuilder makeErrorBuffer() {
+
−		return new StringBuilder(128);
+
−	}
+
−
+
−	public void close() throws IOException {
+
−		inner.close();
+
−	}
+
−}