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
020package org.crsh.cli.impl.parser;
021
022import org.crsh.cli.descriptor.CommandDescriptor;
023import org.crsh.cli.impl.tokenizer.Tokenizer;
024
025import java.util.Iterator;
026import java.util.LinkedList;
027import java.util.NoSuchElementException;
028
029public final class Parser<T> implements Iterator<Event> {
030
031  /** . */
032  private final Tokenizer tokenizer;
033
034  /** . */
035  private final Mode mode;
036
037  /** . */
038  private CommandDescriptor<T> command;
039
040  /** . */
041  private Status status;
042
043  /** . */
044  private final LinkedList<Event> next;
045
046  public Parser(Tokenizer tokenizer, CommandDescriptor<T> command, Mode mode) {
047    this.tokenizer = tokenizer;
048    this.command = command;
049    this.status = new Status.ReadingOption();
050    this.mode = mode;
051    this.next = new LinkedList<Event>();
052  }
053
054  Status getStatus() {
055    return status;
056  }
057
058  public boolean hasNext() {
059    if (next.isEmpty()) {
060      determine();
061    }
062    return next.size() > 0;
063  }
064
065  public Event next() {
066    if (!hasNext()) {
067      throw new NoSuchElementException();
068    }
069    return next.removeFirst();
070  }
071
072  public void remove() {
073    throw new UnsupportedOperationException();
074  }
075
076  private void determine() {
077    while (next.isEmpty()) {
078      Status.Response<T> nextStatus = status.process(new Status.Request<T>(mode, tokenizer, command));
079      if (nextStatus.status != null) {
080        this.status = nextStatus.status;
081      }
082      if (nextStatus.events != null) {
083        next.addAll(nextStatus.events);
084      }
085      if (nextStatus.command != null) {
086        command = (CommandDescriptor<T>)nextStatus.command;
087      }
088    }
089  }
090}