code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2015 Daniel Naber (http://www.danielnaber.de)
   * 
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
   * USA
   */
  package org.languagetool.rules;
  
  import org.languagetool.tools.StringTools;
  
  import java.util.*;
  
  /**
   * Words that can easily be confused - for internal use only.
   * Even though there can be more words in the set, usually there
   * are two, as the factor is specific for this pair of words.
   * @since 3.0
   */
  public class ConfusionSet {
  
    private final Set<ConfusionString> set = new HashSet<>();
    private final long factor;
  
    /**
     * @param factor the factor that one string must be more probable than the other to be considered a correction, must be &gt;= 1
     */
    public ConfusionSet(long factor, List<ConfusionString> confusionStrings) {
      if (factor < 1) {
        throw new IllegalArgumentException("factor must be >= 1: " + factor);
      }
      this.factor = factor;
      set.addAll(Objects.requireNonNull(confusionStrings));
    }
  
    /**
     * @param factor the factor that one string must be more probable than the other to be considered a correction, must be &gt;= 1
     */
    public ConfusionSet(long factor, String... words) {
      if (factor < 1) {
        throw new IllegalArgumentException("factor must be >= 1: " + factor);
      }
      Objects.requireNonNull(words);
      this.factor = factor;
      for (String word : words) {
        set.add(new ConfusionString(word, null));
      }
    }
  
    /* Alternative must be at least this much more probable to be considered correct. */
    public long getFactor() {
      return factor;
    }
  
    public Set<ConfusionString> getSet() {
      return Collections.unmodifiableSet(set);
    }
  
    public Set<ConfusionString> getUppercaseFirstCharSet() {
      Set<ConfusionString> result = new HashSet<>();
      for (ConfusionString s : set) {
        ConfusionString newString = new ConfusionString(StringTools.uppercaseFirstChar(s.getString()), s.getDescription());
        result.add(newString);
      }
      return Collections.unmodifiableSet(result);
    }
  
    @Override
    public String toString() {
      return set.toString();
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || getClass() != o.getClass()) return false;
      ConfusionSet other = (ConfusionSet) o;
      return Objects.equals(set, other.set) && Objects.equals(factor, other.factor);
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(set, factor);
    }
    
  }
  