Back to index...

	/*
	* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.tools.jstat;

	import java.io.*;
	import java.util.*;

	/**
	* A class implementing a simple predictive parser for output format
	* specification language for the jstat command.
	*
	* @author Brian Doherty
	* @since 1.5
	*/
	public class Parser {

	private static boolean pdebug = Boolean.getBoolean("jstat.parser.debug");
	private static boolean ldebug = Boolean.getBoolean("jstat.lex.debug");

	private static final char OPENBLOCK = '{';
	private static final char CLOSEBLOCK = '}';
	private static final char DOUBLEQUOTE = '"';
	private static final char PERCENT_CHAR = '%';
	private static final char OPENPAREN = '(';
	private static final char CLOSEPAREN = ')';

	private static final char OPERATOR_PLUS = '+';
	private static final char OPERATOR_MINUS = '-';
	private static final char OPERATOR_MULTIPLY = '*';
	private static final char OPERATOR_DIVIDE = '/';

	private static final String OPTION = "option";
	private static final String COLUMN = "column";
	private static final String DATA = "data";
	private static final String HEADER = "header";
	private static final String WIDTH = "width";
	private static final String FORMAT = "format";
	private static final String ALIGN = "align";
	private static final String SCALE = "scale";

	private static final String START = OPTION;

	private static final Set scaleKeyWords = Scale.keySet();
	private static final Set alignKeyWords = Alignment.keySet();
	private static String[] otherKeyWords = {
	OPTION, COLUMN, DATA, HEADER, WIDTH, FORMAT, ALIGN, SCALE
	};

	private static char[] infixOps = {
	OPERATOR_PLUS, OPERATOR_MINUS, OPERATOR_MULTIPLY, OPERATOR_DIVIDE
	};

	private static char[] delimiters = {
	OPENBLOCK, CLOSEBLOCK, PERCENT_CHAR, OPENPAREN, CLOSEPAREN
	};


	private static Set<String> reservedWords;

	private StreamTokenizer st;
	private String filename;
	private Token lookahead;
	private Token previous;
	private int columnCount;
	private OptionFormat optionFormat;

	public Parser(String filename) throws FileNotFoundException {
	this.filename = filename;
	Reader r = new BufferedReader(new FileReader(filename));
	}

	public Parser(Reader r) {
	st = new StreamTokenizer(r);

	// allow both c++ style comments
	st.ordinaryChar('/');
	st.wordChars('_','_');
	st.slashSlashComments(true);
	st.slashStarComments(true);

	reservedWords = new HashSet<String>();
	for (int i = 0; i < otherKeyWords.length; i++) {
	reservedWords.add(otherKeyWords[i]);
	}

	for (int i = 0; i < delimiters.length; i++ ) {
	st.ordinaryChar(delimiters[i]);
	}

	for (int i = 0; i < infixOps.length; i++ ) {
	st.ordinaryChar(infixOps[i]);
	}
	}

	/**
	* push back the lookahead token and restore the lookahead token
	* to the previous token.
	*/
	private void pushBack() {
	lookahead = previous;
	st.pushBack();
	}

	/**
	* retrieve the next token, placing the token value in the lookahead
	* member variable, storing its previous value in the previous member
	* variable.
	*/
	private void nextToken() throws ParserException, IOException {
	int t = st.nextToken();
	previous = lookahead;
	lookahead = new Token(st.ttype, st.sval, st.nval);
	log(ldebug, "lookahead = " + lookahead);
	}

	/**
	* match one of the token values in the given set of key words
	* token is assumed to be of type TT_WORD, and the set is assumed
	* to contain String objects.
	*/
	private Token matchOne(Set keyWords) throws ParserException, IOException {
	if ((lookahead.ttype == StreamTokenizer.TT_WORD)
	&& keyWords.contains(lookahead.sval)) {
	Token t = lookahead;
	nextToken();
	return t;
	}
	throw new SyntaxException(st.lineno(), keyWords, lookahead);
	}

	/**
	* match a token with TT_TYPE=type, and the token value is a given sequence
	* of characters.
	*/
	private void match(int ttype, String token)
	throws ParserException, IOException {
	if (lookahead.ttype == ttype && lookahead.sval.compareTo(token) == 0) {
	nextToken();
	} else {
	throw new SyntaxException(st.lineno(), new Token(ttype, token),
	lookahead);
	}
	}

	/**
	* match a token with TT_TYPE=type
	*/
	private void match(int ttype) throws ParserException, IOException {
	if (lookahead.ttype == ttype) {
	nextToken();
	} else {
	throw new SyntaxException(st.lineno(), new Token(ttype), lookahead);
	}
	}

	/**
	* match a token with TT_TYPE=char, where the token value is the given char.
	*/
	private void match(char ttype) throws ParserException, IOException {
	if (lookahead.ttype == (int)ttype) {
	nextToken();
	}
	else {
	throw new SyntaxException(st.lineno(), new Token((int)ttype),
	lookahead);
	}
	}

	/**
	* match a token with TT_TYPE='"', where the token value is a sequence
	* of characters between matching quote characters.
	*/
	private void matchQuotedString() throws ParserException, IOException {
	match(DOUBLEQUOTE);
	}

	/**
	* match a TT_NUMBER token that matches a parsed number value
	*/
	private void matchNumber() throws ParserException, IOException {
	match(StreamTokenizer.TT_NUMBER);
	}

	/**
	* match a TT_WORD token that matches an arbitrary, not quoted token.
	*/
	private void matchID() throws ParserException, IOException {
	match(StreamTokenizer.TT_WORD);
	}

	/**
	* match a TT_WORD token that matches the given string
	*/
	private void match(String token) throws ParserException, IOException {
	match(StreamTokenizer.TT_WORD, token);
	}

	/**
	* determine if the given word is a reserved key word
	*/
	private boolean isReservedWord(String word) {
	return reservedWords.contains(word);
	}

	/**
	* determine if the give work is a reserved key word
	*/
	private boolean isInfixOperator(char op) {
	for (int i = 0; i < infixOps.length; i++) {
	if (op == infixOps[i]) {
	return true;
	}
	}
	return false;
	}

	/**
	* scalestmt -> 'scale' scalespec
	* scalespec -> <see above scaleTerminals array>
	*/
	private void scaleStmt(ColumnFormat cf)
	throws ParserException, IOException {
	match(SCALE);
	Token t = matchOne(scaleKeyWords);
	cf.setScale(Scale.toScale(t.sval));
	String scaleString = t.sval;
	log(pdebug, "Parsed: scale -> " + scaleString);
	}

	/**
	* alignstmt -> 'align' alignspec
	* alignspec -> <see above alignTerminals array>
	*/
	private void alignStmt(ColumnFormat cf)
	throws ParserException, IOException {
	match(ALIGN);
	Token t = matchOne(alignKeyWords);
	cf.setAlignment(Alignment.toAlignment(t.sval));
	String alignString = t.sval;
	log(pdebug, "Parsed: align -> " + alignString);
	}

	/**
	* headerstmt -> 'header' quotedstring
	*/
	private void headerStmt(ColumnFormat cf)
	throws ParserException, IOException {
	match(HEADER);
	String headerString = lookahead.sval;
	matchQuotedString();
	cf.setHeader(headerString);
	log(pdebug, "Parsed: header -> " + headerString);
	}

	/**
	* widthstmt -> 'width' integer
	*/
	private void widthStmt(ColumnFormat cf)
	throws ParserException, IOException {
	match(WIDTH);
	double width = lookahead.nval;
	matchNumber();
	cf.setWidth((int)width);
	log(pdebug, "Parsed: width -> " + width );
	}

	/**
	* formatstmt -> 'format' quotedstring
	*/
	private void formatStmt(ColumnFormat cf)
	throws ParserException, IOException {
	match(FORMAT);
	String formatString = lookahead.sval;
	matchQuotedString();
	cf.setFormat(formatString);
	log(pdebug, "Parsed: format -> " + formatString);
	}

	/**
	* Primary -> Literal \| Identifier \| '(' Expression ')'
	*/
	private Expression primary() throws ParserException, IOException {
	Expression e = null;

	switch (lookahead.ttype) {
	case OPENPAREN:
	match(OPENPAREN);
	e = expression();
	match(CLOSEPAREN);
	break;
	case StreamTokenizer.TT_WORD:
	String s = lookahead.sval;
	if (isReservedWord(s)) {
	throw new SyntaxException(st.lineno(), "IDENTIFIER",
	"Reserved Word: " + lookahead.sval);
	}
	matchID();
	e = new Identifier(s);
	log(pdebug, "Parsed: ID -> " + s);
	break;
	case StreamTokenizer.TT_NUMBER:
	double literal = lookahead.nval;
	matchNumber();
	e = new Literal(new Double(literal));
	log(pdebug, "Parsed: number -> " + literal);
	break;
	default:
	throw new SyntaxException(st.lineno(), "IDENTIFIER", lookahead);
	}
	log(pdebug, "Parsed: primary -> " + e);
	return e;
	}

	/**
	* Unary -> ('+'\|'-') Unary \| Primary
	*/
	private Expression unary() throws ParserException, IOException {
	Expression e = null;
	Operator op = null;

	while (true) {
	switch (lookahead.ttype) {
	case OPERATOR_PLUS:
	match(OPERATOR_PLUS);
	op = Operator.PLUS;
	break;
	case OPERATOR_MINUS:
	match(OPERATOR_MINUS);
	op = Operator.MINUS;
	break;
	default:
	e = primary();
	log(pdebug, "Parsed: unary -> " + e);
	return e;
	}
	Expression e1 = new Expression();
	e1.setOperator(op);
	e1.setRight(e);
	log(pdebug, "Parsed: unary -> " + e1);
	e1.setLeft(new Literal(new Double(0)));
	e = e1;
	}
	}

	/**
	* MultExpression -> Unary (('' \| '/') Unary)
	*/
	private Expression multExpression() throws ParserException, IOException {
	Expression e = unary();
	Operator op = null;

	while (true) {
	switch (lookahead.ttype) {
	case OPERATOR_MULTIPLY:
	match(OPERATOR_MULTIPLY);
	op = Operator.MULTIPLY;
	break;
	case OPERATOR_DIVIDE:
	match(OPERATOR_DIVIDE);
	op = Operator.DIVIDE;
	break;
	default:
	log(pdebug, "Parsed: multExpression -> " + e);
	return e;
	}
	Expression e1 = new Expression();
	e1.setOperator(op);
	e1.setLeft(e);
	e1.setRight(unary());
	e = e1;
	log(pdebug, "Parsed: multExpression -> " + e);
	}
	}

	/**
	* AddExpression -> MultExpression (('+' \| '-') MultExpression)*
	*/
	private Expression addExpression() throws ParserException, IOException {
	Expression e = multExpression();
	Operator op = null;

	while (true) {
	switch (lookahead.ttype) {
	case OPERATOR_PLUS:
	match(OPERATOR_PLUS);
	op = Operator.PLUS;
	break;
	case OPERATOR_MINUS:
	match(OPERATOR_MINUS);
	op = Operator.MINUS;
	break;
	default:
	log(pdebug, "Parsed: addExpression -> " + e);
	return e;
	}
	Expression e1 = new Expression();
	e1.setOperator(op);
	e1.setLeft(e);
	e1.setRight(multExpression());
	e = e1;
	log(pdebug, "Parsed: addExpression -> " + e);
	}
	}

	/**
	* Expression -> AddExpression
	*/
	private Expression expression() throws ParserException, IOException {
	Expression e = addExpression();
	log(pdebug, "Parsed: expression -> " + e);
	return e;
	}

	/**
	* datastmt -> 'data' expression
	*/
	private void dataStmt(ColumnFormat cf) throws ParserException, IOException {
	match(DATA);
	Expression e = expression();
	cf.setExpression(e);
	log(pdebug, "Parsed: data -> " + e);
	}

	/**
	* statementlist -> optionalstmt statementlist
	* optionalstmt -> 'data' expression
	* 'header' quotedstring
	* 'width' integer
	* 'format' formatstring
	* 'align' alignspec
	* 'scale' scalespec
	*/
	private void statementList(ColumnFormat cf)
	throws ParserException, IOException {
	while (true) {
	if (lookahead.ttype != StreamTokenizer.TT_WORD) {
	return;
	}

	if (lookahead.sval.compareTo(DATA) == 0) {
	dataStmt(cf);
	} else if (lookahead.sval.compareTo(HEADER) == 0) {
	headerStmt(cf);
	} else if (lookahead.sval.compareTo(WIDTH) == 0) {
	widthStmt(cf);
	} else if (lookahead.sval.compareTo(FORMAT) == 0) {
	formatStmt(cf);
	} else if (lookahead.sval.compareTo(ALIGN) == 0) {
	alignStmt(cf);
	} else if (lookahead.sval.compareTo(SCALE) == 0) {
	scaleStmt(cf);
	} else {
	return;
	}
	}
	}

	/**
	* optionlist -> columspec optionlist
	* null
	* columspec -> 'column' '{' statementlist '}'
	*/
	private void optionList(OptionFormat of)
	throws ParserException, IOException {
	while (true) {
	if (lookahead.ttype != StreamTokenizer.TT_WORD) {
	return;
	}

	match(COLUMN);
	match(OPENBLOCK);
	ColumnFormat cf = new ColumnFormat(columnCount++);
	statementList(cf);
	match(CLOSEBLOCK);
	cf.validate();
	of.addSubFormat(cf);
	}
	}

	/**
	* optionstmt -> 'option' ID '{' optionlist '}'
	*/
	private OptionFormat optionStmt() throws ParserException, IOException {
	match(OPTION);
	String optionName=lookahead.sval;
	matchID();
	match(OPENBLOCK);
	OptionFormat of = new OptionFormat(optionName);
	optionList(of);
	match(CLOSEBLOCK);
	return of;
	}

	/**
	* parse the specification for the given option identifier
	*/
	public OptionFormat parse(String option)
	throws ParserException, IOException {
	nextToken();

	/*
	* this search stops on the first occurance of an option
	* statement with a name matching the given option. Any
	* duplicate options are ignored.
	*/
	while (lookahead.ttype != StreamTokenizer.TT_EOF) {
	// look for the start symbol
	if ((lookahead.ttype != StreamTokenizer.TT_WORD)
	\|\| (lookahead.sval.compareTo(START) != 0)) {
	// skip tokens until a start symbol is found
	nextToken();
	continue;
	}

	// check if the option name is the one we are interested in
	match(START);

	if ((lookahead.ttype == StreamTokenizer.TT_WORD)
	&& (lookahead.sval.compareTo(option) == 0)) {
	// this is the one we are looking for, parse it
	pushBack();
	return optionStmt();
	} else {
	// not what we are looking for, start skipping tokens
	nextToken();
	}
	}
	return null;
	}

	public Set<OptionFormat> parseOptions() throws ParserException, IOException {
	Set<OptionFormat> options = new HashSet<OptionFormat>();

	nextToken();

	while (lookahead.ttype != StreamTokenizer.TT_EOF) {
	// look for the start symbol
	if ((lookahead.ttype != StreamTokenizer.TT_WORD)
	\|\| (lookahead.sval.compareTo(START) != 0)) {
	// skip tokens until a start symbol is found
	nextToken();
	continue;
	}

	// note: if a duplicate option statement exists, then
	// first one encountered is the chosen definition.
	OptionFormat of = optionStmt();
	options.add(of);
	}
	return options;
	}

	OptionFormat getOptionFormat() {
	return optionFormat;
	}

	private void log(boolean logging, String s) {
	if (logging) {
	System.out.println(s);
	}
	}
	}

Back to index...