code: package com.naveensundarg.shadow.prover.utils;
  
  import com.naveensundarg.shadow.prover.representations.formula.Formula;
  import com.naveensundarg.shadow.prover.representations.value.Value;
  import com.naveensundarg.shadow.prover.representations.value.Variable;
  
  import java.util.List;
  import java.util.Optional;
  import java.util.Set;
  
  /**
   * Created by naveensundarg on 4/13/16.
   */
  public class Problem {
  
  
      private final Set<Formula> assumptions;
  
      private final Formula goal;
  
      private final String name;
      private final String description;
  
  
  
      private final Optional<List<Variable>> answerVariable;
      private final Optional<Set<List<Value>>> answerExpected;
      public Problem(String name, String description, Set<Formula> assumptions, Formula goal) {
  
          this.assumptions = assumptions;
          this.goal = goal;
          this.name = name;
          this.description = description;
          answerExpected = Optional.empty();
  
          answerVariable = Optional.empty();
  
      }
  
          public Problem(String name, String description, Set<Formula> assumptions, Formula goal,
                         List<Variable> answerVariables, Set<List<Value>> expectedAnswers) {
  
          this.assumptions = assumptions;
          this.goal = goal;
          this.name = name;
          this.description = description;
          this.answerExpected = Optional.of(expectedAnswers);
  
          this.answerVariable = Optional.of(answerVariables);
  
      }
  
      public Optional<List<Variable>> getAnswerVariables() {
          return answerVariable;
      }
  
      public Optional<Set<List<Value>>> getAnswersExpected() {
          return answerExpected;
      }
  
      public Set<Formula> getAssumptions() {
          return assumptions;
      }
  
      public Formula getGoal() {
          return goal;
      }
  
      public String getName() {
          return name;
      }
  
      public String getDescription() {
          return description;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
  
          Problem problem = (Problem) o;
  
          if (!assumptions.equals(problem.assumptions)) return false;
          return goal.equals(problem.goal);
  
      }
  
      @Override
      public int hashCode() {
          int result = assumptions.hashCode();
          result = 31 * result + goal.hashCode();
          return result;
      }
  
      @Override
      public String toString() {
          return "Problem{" +
                  "assumptions=" + assumptions +
                  ", goal=" + goal +
                  '}';
      }
  }
  