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.cli.impl.tokenizer; 021 022 import org.crsh.cli.impl.Delimiter; 023 024 import java.util.ArrayList; 025 import java.util.Iterator; 026 import java.util.NoSuchElementException; 027 028 public abstract class Tokenizer implements Iterator<Token> { 029 030 /** . */ 031 private ArrayList<Token> stack; 032 033 /** . */ 034 private int ptr; 035 036 /** . */ 037 private int index = 0; 038 039 protected Tokenizer() { 040 this.stack = new ArrayList<Token>(); 041 this.ptr = 0; 042 } 043 044 public final boolean hasNext() { 045 if (ptr < stack.size()) { 046 return true; 047 } else { 048 Token next = parse(); 049 if (next != null) { 050 stack.add(next); 051 } 052 return next != null; 053 } 054 } 055 056 public final void pushBack(int count) { 057 if (count < 0) { 058 throw new IllegalArgumentException(); 059 } 060 if (ptr - count < 0) { 061 throw new IllegalStateException("Trying to push back too many tokens"); 062 } else { 063 while (count > 0) { 064 index -= stack.get(--ptr).raw.length(); 065 count--; 066 } 067 } 068 } 069 070 public final Token peek() { 071 if (hasNext()) { 072 return stack.get(ptr); 073 } else { 074 return null; 075 } 076 } 077 078 public final Token next() { 079 if (hasNext()) { 080 Token token = stack.get(ptr++); 081 index += token.raw.length(); 082 return token; 083 } else { 084 throw new NoSuchElementException(); 085 } 086 } 087 088 public final void remove() { 089 throw new UnsupportedOperationException(); 090 } 091 092 public final void pushBack() { 093 pushBack(1); 094 } 095 096 protected abstract Token parse(); 097 098 public final int getIndex() { 099 return index; 100 } 101 102 public abstract Delimiter getDelimiter(); 103 }