/*
* Copyright (C) 2011 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.web.controller.regexp;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
* @version $Revision$
*/
public class REParser {
/** . */
private final Lexer lexer;
public REParser(CharSequence seq) {
this.lexer = new Lexer(seq);
}
public REParser(Lexer lexer) {
this.lexer = lexer;
}
public void reset() {
lexer.reset();
}
public int getIndex() {
return lexer.getIndex();
}
public RENode parse() throws SyntaxException {
return parseDisjunction();
}
public boolean isDone() {
return lexer.isDone();
}
public RENode.Disjunction parseDisjunction() throws SyntaxException {
RENode.Alternative alternative = parseAlternative();
if (alternative != null) {
if (lexer.next(Kind.OR)) {
RENode.Disjunction next = parseDisjunction();
return new RENode.Disjunction(alternative, next);
} else {
return new RENode.Disjunction(alternative);
}
} else {
if (lexer.next(Kind.OR)) {
RENode.Disjunction next = parseDisjunction();
return new RENode.Disjunction(null, next);
} else {
return null;
}
}
}
public RENode.Alternative parseAlternative() throws SyntaxException {
RENode.Expr expr = parseExpression();
if (expr != null) {
RENode.Alternative next = parseAlternative();
return new RENode.Alternative(expr, next);
} else {
return null;
}
}
public RENode.Expr parseExpression() throws SyntaxException {
RENode.Expr expr;
if (lexer.next(Kind.BEGIN)) {
expr = new RENode.Assertion.Begin();
} else if (lexer.next(Kind.END)) {
expr = new RENode.Assertion.End();
} else if (lexer.next(Kind.GROUP_OPEN)) {
GroupType groupType = GroupType.forPrefix(lexer.getToken());
RENode.Disjunction group = parseDisjunction();
if (lexer.next(Kind.GROUP_CLOSE)) {
expr = new RENode.Group(group, groupType);
} else {
throw new SyntaxException("Group not closed ");
}
} else {
expr = parseCharacter();
}
if (expr != null) {
Quantifier quantifier = parseQuantifier();
if (quantifier != null) {
expr.setQuantifier(quantifier);
}
}
return expr;
}
private static final Pattern QUANTIFIER_PATTERN = Pattern.compile("^" + "(\\?|\\+|\\*)|\\{([0-9]+)(?:(,)([0-9]*))?\\}"
+ "$");
public Quantifier parseQuantifier() throws SyntaxException {
if (lexer.next(Kind.QUANTIFIER)) {
String quantifierToken = lexer.getToken();
Matcher matcher = QUANTIFIER_PATTERN.matcher(quantifierToken);
if (!matcher.matches()) {
throw new AssertionError("The quantifier token " + quantifierToken + " is not valid");
}
Quantifier.Range range;
if (matcher.group(1) != null) {
switch (quantifierToken.charAt(0)) {
case '*':
range = Quantifier.Range.zeroOrMore();
break;
case '+':
range = Quantifier.Range.oneOrMore();
break;
case '?':
range = Quantifier.Range.onceOrNotAtAll();
break;
default:
throw new AssertionError();
}
} else {
int min = Integer.parseInt(matcher.group(2));
Integer max;
if (matcher.group(3) != null) {
max = matcher.group(4).isEmpty() ? null : Integer.parseInt(matcher.group(4));
} else {
max = min;
}
range = new Quantifier.Range(min, max);
}
Quantifier.Mode mode;
if (lexer.next(Kind.QUANTIFIER_MODE)) {
switch (lexer.getToken().charAt(0)) {
case '?':
mode = Quantifier.Mode.RELUCTANT;
break;
case '+':
mode = Quantifier.Mode.POSSESSIVE;
break;
default:
throw new AssertionError();
}
} else {
mode = Quantifier.Mode.GREEDY;
}
return new Quantifier(mode, range);
} else {
return null;
}
}
public RENode.Atom parseCharacter() throws SyntaxException {
if (lexer.next(Kind.ANY)) {
return new RENode.Any();
} else {
RENode.Atom atom = parseCharacterLiteral();
if (atom == null) {
atom = parseCharacterClass();
}
return atom;
}
}
public RENode.Char parseCharacterLiteral() throws SyntaxException {
if (lexer.next(Kind.LITERAL)) {
return new RENode.Char(lexer.getToken().charAt(0));
} else {
return null;
}
}
public RENode.CharacterClass parseCharacterClass() throws SyntaxException {
RENode.CharacterClassExpr cce = _parseCharacterClass();
if (cce != null) {
return new RENode.CharacterClass(cce);
} else {
return null;
}
}
private RENode.CharacterClassExpr _parseCharacterClass() throws SyntaxException {
if (lexer.next(Kind.CC_OPEN)) {
boolean negated = lexer.getToken().length() > 1;
RENode.CharacterClassExpr expr = parseCharacterClassExpression();
if (expr != null) {
if (lexer.next(Kind.CC_CLOSE)) {
return negated ? new RENode.CharacterClassExpr.Not(expr) : expr;
} else {
throw new SyntaxException("");
}
} else {
throw new SyntaxException("");
}
} else {
return null;
}
}
public RENode.CharacterClassExpr parseCharacterClassExpression() throws SyntaxException {
RENode.CharacterClassExpr left = parseCharacterClassTerm();
if (left != null) {
boolean and = lexer.next(Kind.CC_AND);
RENode.CharacterClassExpr right = parseCharacterClassExpression();
if (right != null) {
if (and) {
return new RENode.CharacterClassExpr.And(left, right);
} else {
return new RENode.CharacterClassExpr.Or(left, right);
}
} else {
return left;
}
} else {
return null;
}
}
public RENode.CharacterClassExpr parseCharacterClassTerm() throws SyntaxException {
RENode.CharacterClassExpr expr = _parseCharacterClass();
if (expr == null) {
RENode.CharacterClassExpr.Char c = parseCharacterClassLiteral();
if (c != null) {
if (lexer.next(Kind.HYPHEN)) {
RENode.CharacterClassExpr.Char to = parseCharacterClassLiteral();
if (to != null) {
expr = new RENode.CharacterClassExpr.Range(c, to);
} else {
throw new SyntaxException();
}
} else {
expr = c;
}
} else if (lexer.next(Kind.ANY)) {
// NOT SURE THIS IS CORRECT
expr = new RENode.CharacterClassExpr.Char('.');
} else if (lexer.next(Kind.BEGIN)) {
// NOT SURE THIS IS CORRECT
expr = new RENode.CharacterClassExpr.Char('^');
} else if (lexer.next(Kind.END)) {
// NOT SURE THIS IS CORRECT
expr = new RENode.CharacterClassExpr.Char('$');
}
}
return expr;
}
public RENode.CharacterClassExpr.Char parseCharacterClassLiteral() throws SyntaxException {
if (lexer.next(Kind.LITERAL)) {
return new RENode.CharacterClassExpr.Char(lexer.getToken().charAt(0));
} else {
return null;
}
}
}