/*
 * Proprietary unpublished source code property of 
 * Simon Brooke <simon@journeyman.cc>.
 * 
 * Copyright (c) 2013 Simon Brooke <simon@journeyman.cc>
 */
package cc.journeyman.milkwood;

import java.util.LinkedList;
import java.util.Queue;

/**
 * An ordered sequence of words. Of course it implements Queue since it is a
 * LinkedList and LinkedList implements Queue, but I want to make it explicitly
 * clear that this is a queue and can be used as such. Different from WordStack
 * which is a Stack.
 *
 * @see WordStack
 *
 * @author Simon Brooke <simon@journeyman.cc>
 */
public class WordSequence extends LinkedList<String> implements Queue<String> {

    private static final long serialVersionUID = 1L;

    /**
     *
     * @param tokens a sequence of tokens
     * @param marker a marker to terminate after the last occurrance of.
     * @return a copy of tokens, truncated at the last occurrance of the marker.
     */
    public WordSequence truncateAtLastInstance(String marker) {
        final WordSequence result = new WordSequence();

        for (String token : this) {
            result.add(token);
            if (token.endsWith(marker) && !this.contains(marker)) {
                /*
                 * If the token we're looking at ends with the marker, and the
                 * remainder of the tokens does not include a token ending with
                 * the marker, we're done. Otherwise, we continue. OK?
                 */
                break;
            }
        }

        return result;
    }

    /**
     * Specialisation: Working around the bug that the tokeniser treats PERIOD
     * as a word character.
     */
    @Override
    public boolean contains(Object target) {
        boolean result = false;
        if (target != null) {
            String marker = target.toString();

            for (String token : this) {
                if (token.endsWith(marker)) {
                    result = true;
                    break;
                }
            }
        }
        return result;
    }
}