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plantuml/src/net/sourceforge/plantuml/ebnf/ShuntingYard.java
Arnaud Roques f846634ce2 wip
2022-09-23 18:53:33 +02:00

72 lines
2.1 KiB
Java

/* ========================================================================
* PlantUML : a free UML diagram generator
* ========================================================================
*
* (C) Copyright 2009-2020, Arnaud Roques
*
* Project Info: http://plantuml.com
*
* If you like this project or if you find it useful, you can support us at:
*
* http://plantuml.com/patreon (only 1$ per month!)
* http://plantuml.com/paypal
*
* This file is part of PlantUML.
*
* PlantUML is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* PlantUML 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 for more details.
*
* You should have received a copy of the GNU General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
*
* Original Author: Arnaud Roques
*
*
*/
package net.sourceforge.plantuml.ebnf;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.Iterator;
import java.util.List;
public class ShuntingYard {
final private List<Token> ouputQueue = new ArrayList<>();
final private Deque<Token> operatorStack = new ArrayDeque<>();
public ShuntingYard(Iterator<Token> it) {
while (it.hasNext()) {
final Token token = it.next();
if (token.getSymbol() == Symbol.LITTERAL || token.getSymbol() == Symbol.TERMINAL_STRING1) {
ouputQueue.add(token);
} else if (token.getSymbol() == Symbol.ALTERNATION) {
operatorStack.addFirst(token);
} else {
throw new UnsupportedOperationException(token.toString());
}
}
while (operatorStack.isEmpty() == false) {
final Token token = operatorStack.removeFirst();
ouputQueue.add(token);
}
}
public final Iterator<Token> getOuputQueue() {
return ouputQueue.iterator();
}
}