package com.infomancers.collections.iterators;

import com.infomancers.collections.yield.Yielder;

import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Copyright (c) 2007, Aviad Ben Dov
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list
 * of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice, this
 * list of conditions and the following disclaimer in the documentation and/or other
 * materials provided with the distribution.
 * 3. Neither the name of Infomancers, Ltd. nor the names of its contributors may be
 * used to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/**
 * Used to iterate strings and string searches in a
 * friendly way.
 */
public final class StringIterators {

    /**
     * Used to iterate over the tokens in a StringTokenizer.
     *
     * @param tokenizer The tokenizer to iterate over.
     * @return An iteration of all result strings.
     * @see java.util.StringTokenizer
     */
    public static Iterable<String> stringTokenizerIterable(final StringTokenizer tokenizer) {
        return new Yielder<String>() {
            @Override
            protected void yieldNextCore() {
                while (tokenizer.hasMoreTokens()) {
                    yieldReturn(tokenizer.nextToken());
                }
            }
        };
    }

    /**
     * Used to iterate over the matches of a pattern in a character sequence.
     *
     * @param target  The character sequence.
     * @param pattern The pattern to match.
     * @return An iteration of all matched strings inside the character sequence.
     */
    public static Iterable<String> regexMatches(final CharSequence target, final Pattern pattern) {
        return new Yielder<String>() {

            @Override
            protected void yieldNextCore() {
                Matcher matcher = pattern.matcher(target);

                while (matcher.find()) {
                    yieldReturn(matcher.group(0));
                }
            }
        };
    }
}