Stream.java

/*
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.controller.regexp;

import java.util.NoSuchElementException;


/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 */
public class Stream {

    /** . */
    private final CharSequence stream;

    /** . */
    private int index;

    public Stream(CharSequence stream) {
        this.stream = stream;
        this.index = 0;
    }

    public int getIndex() {
        return index;
    }

    public void reset() {
        index = 0;
    }

    public boolean hasNext() {
        return hasNext(0);
    }

    public boolean hasNext(int delta) {
        return index + delta < stream.length();
    }

    public boolean hasNext(char c) {
        return hasNext(0, c);
    }

    public boolean hasNext(int delta, char c) {
        int offset = index + delta;
        return offset < stream.length() && stream.charAt(offset) == c;
    }

    public boolean next(char c) {
        boolean a = index < stream.length() && stream.charAt(index) == c;
        if (a) {
            index++;
        }
        return a;
    }

    public Character peek() {
        return peek(0);
    }

    public Character peek(int delta) {
        int offset = index + delta;
        if (offset < stream.length()) {
            return stream.charAt(offset);
        } else {
            return null;
        }
    }

    public char next() {
        if (hasNext()) {
            return stream.charAt(index++);
        } else {
            throw new NoSuchElementException();
        }
    }
}