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 }