mirror of https://github.com/octoleo/plantuml.git
134 lines
5.0 KiB
Java
134 lines
5.0 KiB
Java
/* ========================================================================
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* PlantUML : a free UML diagram generator
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* ========================================================================
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*
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* (C) Copyright 2009-2020, Arnaud Roques
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*
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* Project Info: http://plantuml.com
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*
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* If you like this project or if you find it useful, you can support us at:
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*
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* http://plantuml.com/patreon (only 1$ per month!)
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* http://plantuml.com/paypal
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*
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* This file is part of PlantUML.
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*
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* PlantUML is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* PlantUML distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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* License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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* USA.
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*
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*
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* Original Author: Arnaud Roques
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*
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*
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*/
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package net.sourceforge.plantuml.ebnf;
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import java.util.ArrayDeque;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.Deque;
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import java.util.Iterator;
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import java.util.List;
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public class ShuntingYard {
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final private List<Token> ouputQueue = new ArrayList<>();
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final private Deque<Token> operatorStack = new ArrayDeque<>();
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public ShuntingYard(Iterator<Token> it) {
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while (it.hasNext()) {
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final Token token = it.next();
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// System.err.println("token=" + token);
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// System.err.println("ouputQueue=" + ouputQueue);
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// System.err.println("operatorStack=" + operatorStack);
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if (token.getSymbol() == Symbol.LITTERAL || token.getSymbol() == Symbol.TERMINAL_STRING1
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|| token.getSymbol() == Symbol.TERMINAL_STRING2) {
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ouputQueue.add(token);
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} else if (token.getSymbol().isOperator()) {
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while (thereIsAnOperatorAtTheTopOfTheOperatorStackWithGreaterPrecedence(token))
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ouputQueue.add(operatorStack.removeFirst());
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operatorStack.addFirst(token);
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} else if (token.getSymbol() == Symbol.GROUPING_OPEN) {
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operatorStack.addFirst(token);
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} else if (token.getSymbol() == Symbol.GROUPING_CLOSE) {
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while (operatorStack.peekFirst().getSymbol() != Symbol.GROUPING_OPEN)
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ouputQueue.add(operatorStack.removeFirst());
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if (operatorStack.peekFirst().getSymbol() == Symbol.GROUPING_OPEN)
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operatorStack.removeFirst();
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} else if (token.getSymbol() == Symbol.OPTIONAL_OPEN) {
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operatorStack.addFirst(new Token(Symbol.OPTIONAL, null));
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} else if (token.getSymbol() == Symbol.OPTIONAL_CLOSE) {
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while (thereIsAnOperatorAtTheTopOfTheOperatorStack())
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ouputQueue.add(operatorStack.removeFirst());
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final Token first = operatorStack.removeFirst();
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if (first.getSymbol() != Symbol.OPTIONAL)
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throw new IllegalStateException();
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ouputQueue.add(first);
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} else if (token.getSymbol() == Symbol.REPETITION_OPEN) {
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operatorStack.addFirst(new Token(Symbol.REPETITION_ZERO_OR_MORE, null));
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} else if (token.getSymbol() == Symbol.REPETITION_CLOSE) {
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while (thereIsAnOperatorAtTheTopOfTheOperatorStack())
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ouputQueue.add(operatorStack.removeFirst());
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final Token first = operatorStack.removeFirst();
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if (first.getSymbol() != Symbol.REPETITION_ZERO_OR_MORE)
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throw new IllegalStateException();
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ouputQueue.add(first);
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} else if (token.getSymbol() == Symbol.REPETITION_MINUS_CLOSE) {
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while (thereIsAnOperatorAtTheTopOfTheOperatorStack())
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ouputQueue.add(operatorStack.removeFirst());
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final Token first = operatorStack.removeFirst();
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if (first.getSymbol() != Symbol.REPETITION_ZERO_OR_MORE)
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throw new IllegalStateException();
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ouputQueue.add(new Token(Symbol.REPETITION_ONE_OR_MORE, null));
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} else {
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throw new UnsupportedOperationException(token.toString());
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}
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}
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while (operatorStack.isEmpty() == false) {
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final Token token = operatorStack.removeFirst();
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if (token.getSymbol() == Symbol.OPTIONAL || token.getSymbol() == Symbol.REPETITION_ONE_OR_MORE
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|| token.getSymbol() == Symbol.REPETITION_ZERO_OR_MORE) {
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ouputQueue.clear();
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return;
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}
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ouputQueue.add(token);
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}
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}
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private boolean thereIsAFunctionAtTheTopOfTheOperatorStack() {
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final Token top = operatorStack.peekFirst();
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return top != null && top.getSymbol().isFunction();
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}
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private boolean thereIsAnOperatorAtTheTopOfTheOperatorStack() {
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final Token top = operatorStack.peekFirst();
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return top != null && top.getSymbol().isOperator();
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}
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private boolean thereIsAnOperatorAtTheTopOfTheOperatorStackWithGreaterPrecedence(Token token) {
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final Token top = operatorStack.peekFirst();
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if (top != null && top.getSymbol().isOperator()
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&& top.getSymbol().getPriority() > token.getSymbol().getPriority())
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return true;
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return false;
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}
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public final List<Token> getOuputQueue() {
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return Collections.unmodifiableList(ouputQueue);
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}
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}
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