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