+
−/*
+
− * 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.mcl.parser;
+
−
+
−
+
−/**
+
− * Interface for parsers in MCL.  The parser family in MCL is set up as
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− * a reusable object.  This allows the same parser to be used again for
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− * the same type of work.  While this is a very unnatural solution in
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− * the Java language, it prevents many object creations on a low level
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− * of the protocol.  This favours performance.
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− * 
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− * A typical parser has a method parse() which takes a String, and the
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− * methods hasNext() and next() to retrieve the values that were
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− * extracted by the parser.  Parser specific methods may be available to
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− * perform common tasks.
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− *
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− * @author Fabian Groffen
+
− */
+
−public abstract class MCLParser {
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−	/** The String values found while parsing.  Public, you may touch it. */
+
−	public final String values[];
+
−	protected int colnr = 0;
+
−
+
−	/**
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−	 * Creates an MCLParser targetted at a given number of field values.
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−	 * The lines parsed by an instance of this MCLParser should have
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−	 * exactly capacity field values.
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−	 *
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−	 * @param capacity the number of field values to expect
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−	 */
+
−	protected MCLParser(final int capacity) {
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−		values = new String[capacity];
+
−	}
+
−
+
−	/**
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−	 * Parse the given string, and populate the internal field array
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−	 * to allow for next() and hasNext() calls.
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−	 *
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−	 * @param source the String containing the line to parse
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−	 * @return value
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−	 * @throws MCLParseException if source cannot be (fully) parsed by
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−	 * this parser
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−	 * @see #next()
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−	 * @see #hasNext()
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−	 */
+
−	abstract public int parse(final String source) throws MCLParseException;
+
−
+
−	/**
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−	 * Repositions the internal field offset to the start, such that the
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−	 * next call to next() will return the first field again.
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−	 */
+
−	final public void reset() {
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−		colnr = 0;
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−	}
+
−
+
−	/**
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−	 * Returns whether the next call to next() or nextInt() succeeds.
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−	 *
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−	 * @return true if the next call to next() or nextInt() is bound to
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−	 * succeed
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−	 * @see #next()
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−	 */
+
−	final public boolean hasNext() {
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−		return colnr < values.length;
+
−	}
+
−
+
−	/**
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−	 * Returns the current field value, and advances the field counter
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−	 * to the next value.  This method may fail with a RuntimeError if
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−	 * the current field counter is out of bounds.  Call hasNext() to
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−	 * determine if the call to next() will succeed.
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−	 *
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−	 * @return the current field value
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−	 * @see #hasNext()
+
−	 */
+
−	final public String next() {
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−		return values[colnr++];
+
−	}
+
−}