001 /* 002 * Copyright (C) 2012 eXo Platform SAS. 003 * 004 * This is free software; you can redistribute it and/or modify it 005 * under the terms of the GNU Lesser General Public License as 006 * published by the Free Software Foundation; either version 2.1 of 007 * the License, or (at your option) any later version. 008 * 009 * This software is distributed in the hope that it will be useful, 010 * but WITHOUT ANY WARRANTY; without even the implied warranty of 011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 012 * Lesser General Public License for more details. 013 * 014 * You should have received a copy of the GNU Lesser General Public 015 * License along with this software; if not, write to the Free 016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org. 018 */ 019 020 package org.crsh.shell.impl.command; 021 022 import org.crsh.command.SyntaxException; 023 024 public class PipeLineParser { 025 026 /** . */ 027 private Tokenizer tokenizer; 028 029 /** . */ 030 private Token token; 031 032 public PipeLineParser(CharSequence s) { 033 this.tokenizer = new Tokenizer(s); 034 this.token = tokenizer.nextToken(); 035 } 036 037 public PipeLineFactory parse() { 038 if (token == Token.EOF) { 039 return null; 040 } else { 041 return parseExpr(); 042 } 043 } 044 045 private PipeLineFactory parseExpr() { 046 if (token instanceof Token.Command) { 047 Token.Command command = (Token.Command)token; 048 token = tokenizer.nextToken(); 049 PipeLineFactory next; 050 if (token == Token.EOF) { 051 next = null; 052 } else if (token == Token.PIPE) { 053 token = tokenizer.nextToken(); 054 next = parseExpr(); 055 } else { 056 throw new SyntaxException("Syntax error"); 057 } 058 return new PipeLineFactory(command.line, next); 059 } else { 060 throw new SyntaxException("Syntax error"); 061 } 062 } 063 }