Package com.tulskiy.musique.playlist.formatting

Source Code of com.tulskiy.musique.playlist.formatting.Parser

/*
* Copyright (c) 2008, 2009, 2010 Denis Tulskiy
*
* This program 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 3 of the License, or
* (at your option) any later version.
*
* This program 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
* version 3 along with this work.  If not, see <http://www.gnu.org/licenses/>.
*/

package com.tulskiy.musique.playlist.formatting;

import com.tulskiy.musique.playlist.formatting.tokens.Expression;
import com.tulskiy.musique.playlist.formatting.tokens.MethodExpression;
import com.tulskiy.musique.playlist.formatting.tokens.ParameterExpression;
import com.tulskiy.musique.playlist.formatting.tokens.TextExpression;

import java.util.ArrayList;
import java.util.Stack;
import java.util.StringTokenizer;

/**
* @Author: Denis Tulskiy
* @Date: Feb 6, 2010
*/
public class Parser {
    public static Expression parse(String text) {
        text = text.replaceAll("\\s*,\\s*", ",");
        StringTokenizer st = new StringTokenizer(text, "$%,\'[])", true);
        MethodExpression root = new MethodExpression("eval");
        Stack<MethodExpression> stack = new Stack<MethodExpression>();
        stack.push(root);
        try {
            while (st.hasMoreTokens()) {
                String token = st.nextToken();

                if (token.equals("%")) {
                    if (st.hasMoreTokens()) {
                        String s = st.nextToken();
                        s = Character.toUpperCase(s.charAt(0)) + s.substring(1);
                        stack.peek().addExpression(new ParameterExpression(s));
                        if (st.hasMoreTokens() && !st.nextToken().equals("%")) {
                            break;
                        }
                    }
                } else if (token.equals("$")) {
                    if (st.hasMoreTokens()) {
                        String s = st.nextToken();
                        s = s.substring(0, s.length() - 1);
                        MethodExpression m = new MethodExpression(s);
                        stack.peek().addExpression(m);
                        stack.push(m);
                    }
                } else if (token.equals(")") || token.equals("]")) {
                    stack.pop();
                } else if (token.equals(",")) {
                    //ignore
                } else if (token.equals("\'")) {
                    StringBuilder sb = new StringBuilder();
                    while (st.hasMoreTokens()) {
                        String str = st.nextToken();
                        if (str.equals("\'"))
                            break;
                        sb.append(str);
                    }

                    stack.peek().addExpression(new TextExpression(sb.toString()));
                } else if (token.equals("[")) {
                    MethodExpression m = new MethodExpression("notNull");
                    stack.peek().addExpression(m);
                    stack.push(m);
                } else {
                    stack.peek().addExpression(new TextExpression(token));
                }
            }
        } catch (Exception e) {
//            e.printStackTrace();
        }

        ArrayList<Expression> e = root.getExpressions();
        if (e.size() == 1) {
            return e.get(0);
        } else {
            return root;
        }
    }
}
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