code: ///////////////////////////////////////////////////////////////////////////
  //                   __                _      _   ________               //
  //                  / /   ____  ____ _(_)____/ | / / ____/               //
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  //                           /____/                                      //
  //                                                                       //
  //               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.solvers.maxsat.algorithms;
  
  import org.logicng.configurations.Configuration;
  import org.logicng.configurations.ConfigurationType;
  
  import java.io.PrintStream;
  
  /**
   * The configuration object for a MaxSAT solver.
   * @version 2.0.0
   * @since 1.0
   */
  public final class MaxSATConfig extends Configuration {
  
      /**
       * The solver type of the underlying SAT solver.
       */
      public enum SolverType {
          MINISAT, GLUCOSE
      }
  
      /**
       * The incremental strategy for cardinality and pseudo-boolean constraints.
       */
      public enum IncrementalStrategy {
          NONE, ITERATIVE
      }
  
      /**
       * The AMO encoding.
       */
      public enum AMOEncoding {
          LADDER
      }
  
      /**
       * The pseudo Boolean encoding.
       */
      public enum PBEncoding {
          SWC
      }
  
      /**
       * The cardinality constraint encoding.
       */
      public enum CardinalityEncoding {
          TOTALIZER, MTOTALIZER
      }
  
      /**
       * The weight strategy.
       */
      public enum WeightStrategy {
          NONE, NORMAL, DIVERSIFY
      }
  
      /**
       * The verbosity of the solver.
       */
      public enum Verbosity {
          NONE, SOME
      }
  
      final IncrementalStrategy incrementalStrategy;
      final AMOEncoding amoEncoding;
      final PBEncoding pbEncoding;
      final CardinalityEncoding cardinalityEncoding;
      final WeightStrategy weightStrategy;
      final SolverType solverType;
      final Verbosity verbosity;
      final PrintStream output;
      final boolean symmetry;
      final int limit;
      final boolean bmo;
  
      /**
       * Constructor for a MaxSAT configuration.
       * @param builder the builder
       */
      private MaxSATConfig(final Builder builder) {
          super(ConfigurationType.MAXSAT);
          this.incrementalStrategy = builder.incrementalStrategy;
          this.amoEncoding = builder.amoEncoding;
          this.pbEncoding = builder.pbEncoding;
          this.cardinalityEncoding = builder.cardinalityEncoding;
          this.weightStrategy = builder.weightStrategy;
          this.solverType = builder.solverType;
          this.verbosity = builder.verbosity;
          this.output = builder.output;
          this.symmetry = builder.symmetry;
          this.limit = builder.limit;
          this.bmo = builder.bmo;
      }
  
      /**
       * Copy Constructor with another cardinality encoding.
       * @param config              the configuration to copy
       * @param cardinalityEncoding the cardinality encoding
       */
      public MaxSATConfig(final MaxSATConfig config, final CardinalityEncoding cardinalityEncoding) {
          super(ConfigurationType.MAXSAT);
          this.incrementalStrategy = config.incrementalStrategy;
          this.amoEncoding = config.amoEncoding;
          this.pbEncoding = config.pbEncoding;
          this.cardinalityEncoding = cardinalityEncoding;
          this.weightStrategy = config.weightStrategy;
          this.solverType = config.solverType;
          this.verbosity = config.verbosity;
          this.output = config.output;
          this.symmetry = config.symmetry;
          this.limit = config.limit;
          this.bmo = config.bmo;
      }
  
      /**
       * Copy Constructor with another incrementality strategy.
       * @param config              the configuration to copy
       * @param incrementalStrategy the incrementality strategy
       */
      public MaxSATConfig(final MaxSATConfig config, final IncrementalStrategy incrementalStrategy) {
          super(ConfigurationType.MAXSAT);
          this.incrementalStrategy = incrementalStrategy;
          this.amoEncoding = config.amoEncoding;
          this.pbEncoding = config.pbEncoding;
          this.cardinalityEncoding = config.cardinalityEncoding;
          this.weightStrategy = config.weightStrategy;
          this.solverType = config.solverType;
          this.verbosity = config.verbosity;
          this.output = config.output;
          this.symmetry = config.symmetry;
          this.limit = config.limit;
          this.bmo = config.bmo;
      }
  
      /**
       * 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("MaxSATConfig{").append(System.lineSeparator());
          sb.append("incrementalStrategy=").append(this.incrementalStrategy).append(System.lineSeparator());
          sb.append("pbEncoding=").append(this.amoEncoding).append(System.lineSeparator());
          sb.append("pbEncoding=").append(this.pbEncoding).append(System.lineSeparator());
          sb.append("cardinalityEncoding=").append(this.cardinalityEncoding).append(System.lineSeparator());
          sb.append("weightStrategy=").append(this.weightStrategy).append(System.lineSeparator());
          sb.append("solverType=").append(this.solverType).append(System.lineSeparator());
          sb.append("verbosity=").append(this.verbosity).append(System.lineSeparator());
          sb.append("symmetry=").append(this.symmetry).append(System.lineSeparator());
          sb.append("limit=").append(this.limit).append(System.lineSeparator());
          sb.append("bmo=").append(this.bmo).append(System.lineSeparator());
          sb.append("}");
          return sb.toString();
      }
  
      /**
       * The builder for a MaxSAT configuration.
       */
      public static class Builder {
          private final AMOEncoding amoEncoding;
          private final PBEncoding pbEncoding;
          private IncrementalStrategy incrementalStrategy = IncrementalStrategy.NONE;
          private CardinalityEncoding cardinalityEncoding = CardinalityEncoding.TOTALIZER;
          private WeightStrategy weightStrategy = WeightStrategy.NONE;
          private SolverType solverType = SolverType.GLUCOSE;
          private Verbosity verbosity = Verbosity.NONE;
          private PrintStream output = System.out;
          private boolean symmetry = true;
          private int limit = Integer.MAX_VALUE;
          private boolean bmo = true;
  
          /**
           * Constructor for the builder.
           */
          private Builder() {
              this.amoEncoding = AMOEncoding.LADDER;
              this.pbEncoding = PBEncoding.SWC;
          }
  
          /**
           * Sets the incremental strategy. The default value is {@code NONE}.
           * @param inc the incremental strategy
           * @return the builder
           */
          public Builder incremental(final IncrementalStrategy inc) {
              this.incrementalStrategy = inc;
              return this;
          }
  
          /**
           * Sets the cardinality encoding. The default value is {@code TOTALIZER}.
           * @param card the cardinality encoding
           * @return the builder
           */
          public Builder cardinality(final CardinalityEncoding card) {
              this.cardinalityEncoding = card;
              return this;
          }
  
          /**
           * Sets the weight strategy. The default value is {@code NONE}.
           * @param weight the weight strategy
           * @return the builder
           */
          public Builder weight(final WeightStrategy weight) {
              this.weightStrategy = weight;
              return this;
          }
  
          /**
           * Sets the underlying solver type. The default value is {@code GLUCOSE}.
           * @param solver the underlying solver type
           * @return the builder
           */
          public Builder solver(final SolverType solver) {
              this.solverType = solver;
              return this;
          }
  
          /**
           * Enables symmetry handling. The default value is {@code true}.
           * @param symm {code true} if symmetry handling should be activated, {@code false} otherwise
           * @return the builder
           */
          public Builder symmetry(final boolean symm) {
              this.symmetry = symm;
              return this;
          }
  
          /**
           * Sets the symmetry limit. The default value is {@code Integer.MAX_VALUE}.
           * @param lim the symmetry limit
           * @return the builder
           */
          public Builder limit(final int lim) {
              this.limit = lim;
              return this;
          }
  
          /**
           * Enables BMO (Boolean Multilevel Optimization). The default value is {@code true}.
           * @param bmo {code true} if BMO should be activated, {@code false} otherwise
           * @return the builder
           */
          public Builder bmo(final boolean bmo) {
              this.bmo = bmo;
              return this;
          }
  
          /**
           * Sets the verbosity. The default value is {@code NONE}.  If you set the verbosity to {@code SOME} you have also to
           * set an output stream.
           * @param verb the verbosity level
           * @return the builder
           */
          public Builder verbosity(final Verbosity verb) {
              this.verbosity = verb;
              return this;
          }
  
          /**
           * Sets the output stream for logging information.  The default ist {@code System.out}.
           * @param output the output stream for logging information
           * @return the builder
           */
          public Builder output(final PrintStream output) {
              this.output = output;
              return this;
          }
  
          /**
           * Builds the configuration.
           * @return the configuration.
           */
          public MaxSATConfig build() {
              return new MaxSATConfig(this);
          }
      }
  }
  