code: ///////////////////////////////////////////////////////////////////////////
  //                   __                _      _   ________               //
  //                  / /   ____  ____ _(_)____/ | / / ____/               //
  //                 / /   / __ \/ __ `/ / ___/  |/ / / __                 //
  //                / /___/ /_/ / /_/ / / /__/ /|  / /_/ /                 //
  //               /_____/\____/\__, /_/\___/_/ |_/\____/                  //
  //                           /____/                                      //
  //                                                                       //
  //               The Next Generation Logic Library                       //
  //                                                                       //
  ///////////////////////////////////////////////////////////////////////////
  //                                                                       //
  //  Copyright 2015-20xx Christoph Zengler                                //
  //                                                                       //
  //  Licensed 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.logicng.explanations.mus;
  
  import org.logicng.configurations.Configuration;
  import org.logicng.configurations.ConfigurationType;
  import org.logicng.handlers.SATHandler;
  
  /**
   * The configuration object for the MUS generation.
   * @version 2.1.0
   * @since 1.1
   */
  public final class MUSConfig extends Configuration {
  
      /**
       * The algorithm for the MUS generation.
       */
      public enum Algorithm {
          DELETION, PLAIN_INSERTION
      }
  
      final Algorithm algorithm;
      final SATHandler handler;
  
      /**
       * Constructs a new configuration with a given type.
       * @param builder the builder
       */
      private MUSConfig(final Builder builder) {
          super(ConfigurationType.MUS);
          this.algorithm = builder.algorithm;
          this.handler = builder.handler;
      }
  
      /**
       * Returns a new builder for the configuration.
       * @return the builder
       */
      public static Builder builder() {
          return new Builder();
      }
  
      @Override
      public String toString() {
          final StringBuilder sb = new StringBuilder("MUSConfig{").append(System.lineSeparator());
          sb.append("algorithm=").append(this.algorithm).append(System.lineSeparator());
          sb.append("}").append(System.lineSeparator());
          return sb.toString();
      }
  
      /**
       * The builder for a MUS configuration.
       */
      public static class Builder {
  
          private Algorithm algorithm = Algorithm.DELETION;
          private SATHandler handler = null;
  
          private Builder() {
              // Initialize only via factory
          }
  
          /**
           * Sets the algorithm for the MUS generation. The default value is {@code DELETION}.
           * @param algorithm the algorithm for the MUS generation
           * @return the builder
           */
          public Builder algorithm(final Algorithm algorithm) {
              this.algorithm = algorithm;
              return this;
          }
  
          /**
           * Sets the SAT handler for the MUS generation.
           * @param handler the SAT handler
           * @return the current builder
           */
          public Builder handler(final SATHandler handler) {
              this.handler = handler;
              return this;
          }
  
          /**
           * Builds the configuration.
           * @return the configuration.
           */
          public MUSConfig build() {
              return new MUSConfig(this);
          }
      }
  }
  