001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.text.matcher;
019
020/**
021 * Determines if a character array portion matches.
022 *
023 * @since 1.3
024 */
025public interface StringMatcher {
026
027    /**
028     * Returns the number of matching characters, zero for no match.
029     * <p>
030     * This method is called to check for a match. The parameter <code>pos</code> represents the current position to be
031     * checked in the string <code>buffer</code> (a character array which must not be changed). The API guarantees that
032     * <code>pos</code> is a valid index for <code>buffer</code>.
033     * <p>
034     * The character array may be larger than the active area to be matched. Only values in the buffer between the
035     * specified indices may be accessed.
036     * <p>
037     * The matching code may check one character or many. It may check characters preceding <code>pos</code> as well as
038     * those after, so long as no checks exceed the bounds specified.
039     * <p>
040     * It must return zero for no match, or a positive number if a match was found. The number indicates the number of
041     * characters that matched.
042     *
043     * @param buffer
044     *            the text content to match against, do not change
045     * @param pos
046     *            the starting position for the match, valid for buffer
047     * @param bufferStart
048     *            the first active index in the buffer, valid for buffer
049     * @param bufferEnd
050     *            the end index (exclusive) of the active buffer, valid for buffer
051     * @return the number of matching characters, or zero if there is no match
052     */
053    int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd);
054
055}