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 */
017package org.apache.commons.text.diff;
018
019import java.util.List;
020
021/**
022 * This interface is devoted to handle synchronized replacement sequences.
023 *
024 * @param <T> object type
025 * @see ReplacementsFinder
026 * @since 1.0
027 */
028public interface ReplacementsHandler<T> {
029
030    /**
031     * Handle two synchronized sequences.
032     * <p>
033     * This method is called by a {@link ReplacementsFinder ReplacementsFinder}
034     * instance when it has synchronized two sub-sequences of object arrays
035     * being compared, and at least one of the sequences is non-empty. Since the
036     * sequences are synchronized, the objects before the two sub-sequences are
037     * equals (if they exist). This property also holds for the objects after
038     * the two sub-sequences.
039     * </p>
040     * <p>
041     * The replacement is defined as replacing the {@code from}
042     * sub-sequence into the {@code to} sub-sequence.
043     * </p>
044     *
045     * @param skipped  number of tokens skipped since the last call (i.e. number of
046     *   tokens that were in both sequences), this number should be strictly positive
047     *   except on the very first call where it can be zero (if the first object of
048     *   the two sequences are different)
049     * @param from  sub-sequence of objects coming from the first sequence
050     * @param to  sub-sequence of objects coming from the second sequence
051     */
052    void handleReplacement(int skipped, List<T> from, List<T> to);
053
054}