| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.text.diff; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * This class gathers all the {@link EditCommand commands} needed to transform |
| * one objects sequence into another objects sequence. |
| * <p> |
| * An edit script is the most general view of the differences between two |
| * sequences. It is built as the result of the comparison between two sequences |
| * by the {@link StringsComparator StringsComparator} class. The user can |
| * walk through it using the <em>visitor</em> design pattern. |
| * <p> |
| * It is guaranteed that the objects embedded in the {@link InsertCommand insert |
| * commands} come from the second sequence and that the objects embedded in |
| * either the {@link DeleteCommand delete commands} or {@link KeepCommand keep |
| * commands} come from the first sequence. This can be important if subclassing |
| * is used for some elements in the first sequence and the {@code equals} |
| * method is specialized. |
| * |
| * @see StringsComparator |
| * @see EditCommand |
| * @see CommandVisitor |
| * @see ReplacementsHandler |
| * |
| * @param <T> object type |
| * @since 1.0 |
| */ |
| public class EditScript<T> { |
| |
| /** Container for the commands. */ |
| private final List<EditCommand<T>> commands; |
| |
| /** Length of the longest common subsequence. */ |
| private int lcsLength; |
| |
| /** Number of modifications. */ |
| private int modifications; |
| |
| /** |
| * Simple constructor. Creates a new empty script. |
| */ |
| public EditScript() { |
| commands = new ArrayList<>(); |
| lcsLength = 0; |
| modifications = 0; |
| } |
| |
| /** |
| * Add a keep command to the script. |
| * |
| * @param command command to add |
| */ |
| public void append(final KeepCommand<T> command) { |
| commands.add(command); |
| ++lcsLength; |
| } |
| |
| /** |
| * Add an insert command to the script. |
| * |
| * @param command command to add |
| */ |
| public void append(final InsertCommand<T> command) { |
| commands.add(command); |
| ++modifications; |
| } |
| |
| /** |
| * Add a delete command to the script. |
| * |
| * @param command command to add |
| */ |
| public void append(final DeleteCommand<T> command) { |
| commands.add(command); |
| ++modifications; |
| } |
| |
| /** |
| * Visit the script. The script implements the <em>visitor</em> design |
| * pattern, this method is the entry point to which the user supplies its |
| * own visitor, the script will be responsible to drive it through the |
| * commands in order and call the appropriate method as each command is |
| * encountered. |
| * |
| * @param visitor the visitor that will visit all commands in turn |
| */ |
| public void visit(final CommandVisitor<T> visitor) { |
| for (final EditCommand<T> command : commands) { |
| command.accept(visitor); |
| } |
| } |
| |
| /** |
| * Get the length of the Longest Common Subsequence (LCS). The length of the |
| * longest common subsequence is the number of {@link KeepCommand keep |
| * commands} in the script. |
| * |
| * @return length of the Longest Common Subsequence |
| */ |
| public int getLCSLength() { |
| return lcsLength; |
| } |
| |
| /** |
| * Get the number of effective modifications. The number of effective |
| * modification is the number of {@link DeleteCommand delete} and |
| * {@link InsertCommand insert} commands in the script. |
| * |
| * @return number of effective modifications |
| */ |
| public int getModifications() { |
| return modifications; |
| } |
| |
| } |