+
−/*
+
− * SPDX-License-Identifier: MPL-2.0
+
− *
+
− * 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 2024, 2025 MonetDB Foundation;
+
− * Copyright August 2008 - 2023 MonetDB B.V.;
+
− * Copyright 1997 - July 2008 CWI.
+
− */
+
−
+
−package org.monetdb.mcl.io;
+
−
+
−import java.io.BufferedReader;
+
−import java.io.IOException;
+
−import java.io.InputStream;
+
−import java.io.Reader;
+
−import java.nio.charset.Charset;
+
−
+
−/**
+
− * Helper class to read and classify the lines of a query response.
+
− *
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− * This class wraps and buffers the Reader on which the responses come in.
+
− * Use {@link #getLine()} to get the current line, {@link #getLineType()}
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− * to get its {@link LineType} and {@link #advance()} to proceed to the
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− * next line.
+
− *
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− * Initially, the line type is set to LineType.UNKNOWN and the line
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− * is set to null. When the end of the result set has been reached the line type
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− * will remain LineType.PROMPT and the line will again be null.
+
− *
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− * To start reading the next response, call {@link #resetLineType()}. This
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− * is usually done automatically by the accompanying {@link BufferedMCLWriter}
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− * whenever a new request is sent to the server.
+
− *
+
− * @author Fabian Groffen
+
− * @see org.monetdb.mcl.net.MapiSocket
+
− * @see org.monetdb.mcl.io.BufferedMCLWriter
+
− */
+
−public final class BufferedMCLReader {
+
−
+
−	private final BufferedReader inner;
+
−	private String current = null;
+
−	private LineType lineType = LineType.UNKNOWN;
+
−
+
−	/**
+
−	 * 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
+
−	 */
+
−	public BufferedMCLReader(final Reader in) {
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−		inner = new BufferedReader(in);
+
−	}
+
−
+
−	/**
+
−	 * 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
+
−	 * @param cs A Charset
+
−	 */
+
−	public BufferedMCLReader(final InputStream in, final Charset cs) {
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−		this(new java.io.InputStreamReader(in, cs));
+
−	}
+
−
+
−	/**
+
−	 * Proceed to the next line of the response.
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−	 * 
+
−	 * Set line type to PROMPT and line to null if the end of the response
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−	 * has been reached.
+
−	 * @throws IOException if exception occurred during reading
+
−	 */
+
−	public void advance() throws IOException {
+
−		if (lineType == LineType.PROMPT)
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−			return;
+
−
+
−		current = inner.readLine();
+
−		lineType = LineType.classify(current);
+
−		if (lineType == LineType.ERROR && current != null && !current.matches("^![0-9A-Z]{5}!.+")) {
+
−			current = "!22000!" + current.substring(1);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Reset the linetype to UNKNOWN.
+
−	 */
+
−	public void resetLineType() {
+
−		lineType = LineType.UNKNOWN;
+
−	}
+
−
+
−	/**
+
−	 * Return the current line, or null if we're at the end or before the beginning.
+
−	 * @return the current line or null
+
−	 */
+
−	public String getLine() {
+
−		return current;
+
−	}
+
−
+
−	/**
+
−	 * Return a substring of the current line, or null if we're at the end or before the beginning.
+
−	 *
+
−	 * @param start beginIndex
+
−	 * @return the current line or null
+
−	 */
+
−	public String getLine(int start) {
+
−		String line = getLine();
+
−		if (line != null)
+
−			line = line.substring(start);
+
−		return line;
+
−	}
+
−
+
−	/**
+
−	 * getLineType returns the type of the current line.
+
−	 *
+
−	 * @return Linetype representing the kind of line this is, one of the
+
−	 *         following enums: UNKNOWN, HEADER, ERROR, RESULT,
+
−	 *         PROMPT, MORE, FILETRANSFER, SOHEADER, REDIRECT, INFO
+
−	 */
+
−	public LineType getLineType() {
+
−		return lineType;
+
−	}
+
−
+
−	/**
+
−	 * Discard the remainder of the response but collect any further error messages.
+
−	 *
+
−	 * @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
+
−	 */
+
−	final public String discardRemainder() throws IOException {
+
−		return discard(null);
+
−	}
+
−
+
−	/**
+
−	 * Discard the remainder of the response but collect any further error messages.
+
−	 *
+
−	 * @param error A string containing earlier error messages to include in the error report.
+
−	 * @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
+
−	 */
+
−	final public String discardRemainder(String error) throws IOException {
+
−		final StringBuilder sb;
+
−
+
−		if (error != null) {
+
−			sb = makeErrorBuffer();
+
−			sb.append(error);
+
−		} else {
+
−			sb = null;
+
−		}
+
−		return discard(sb);
+
−	}
+
−
+
−	/**
+
−	 * Discard the remainder of the response but collect any further error messages.
+
−	 *
+
−	 * @param errmsgs An optional StringBuilder object containing earlier error messages to include in the error report.
+
−	 * @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 synchronized String discard(StringBuilder errmsgs) throws IOException {
+
−		while (lineType != LineType.PROMPT) {
+
−			advance();
+
−			if (getLine() == null)
+
−				throw new IOException("Connection to server lost!");
+
−			if (getLineType() == LineType.ERROR) {
+
−				if (errmsgs == null)
+
−					errmsgs = new StringBuilder(128);
+
−				errmsgs.append('\n').append(getLine().substring(1));
+
−			}
+
−		}
+
−		if (errmsgs == null)
+
−			return null;
+
−		return errmsgs.toString().trim();
+
−	}
+
−
+
−	private final StringBuilder makeErrorBuffer() {
+
−		return new StringBuilder(128);
+
−	}
+
−
+
−	/**
+
−	 * Close the wrapped Reader.
+
−	 * @throws IOException if an IO exception occurs while talking to the server
+
−	 */
+
−	public void close() throws IOException {
+
−		inner.close();
+
−	}
+
−}