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/*
 * 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.collections4.sequence;

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.
 * 

* 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 SequencesComparator SequencesComparator} class. The user can * walk through it using the visitor design pattern. *

* 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 equals * method is specialized. * * @see SequencesComparator * @see EditCommand * @see CommandVisitor * @see ReplacementsHandler * * @since 4.0 * @version $Id: EditScript.java 1477760 2013-04-30 18:34:03Z tn $ */ public class EditScript { /** Container for the commands. */ private final List> 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 command) { commands.add(command); ++lcsLength; } /** * Add an insert command to the script. * * @param command command to add */ public void append(final InsertCommand command) { commands.add(command); ++modifications; } /** * Add a delete command to the script. * * @param command command to add */ public void append(final DeleteCommand command) { commands.add(command); ++modifications; } /** * Visit the script. The script implements the visitor 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 visitor) { for (final EditCommand 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; } }





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