// =================== DO NOT EDIT THIS FILE ====================
   //  Generated by Modello Velocity from model.vm
   //  template, any modifications will be overwritten.
   // ==============================================================
   package org.apache.maven.api.model;
   
   import java.io.Serializable;
   import java.util.Collections;
   import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.Set;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  import org.apache.maven.api.annotations.Experimental;
  import org.apache.maven.api.annotations.Generated;
  import org.apache.maven.api.annotations.Immutable;
  import org.apache.maven.api.annotations.Nonnull;
  import org.apache.maven.api.annotations.NotThreadSafe;
  import org.apache.maven.api.annotations.ThreadSafe;
  
  /**
   * Describes the prerequisites a project can have.
   */
  @Experimental
  @Generated @ThreadSafe @Immutable
  public class Prerequisites
      implements Serializable, InputLocationTracker
  {
      /**
       * For a plugin project (packaging is {@code maven-plugin}), the minimum version of
       * Maven required to use the resulting plugin.
       */
      final String maven;
      /** Locations */
      final Map<Object, InputLocation> locations;
      /** Location tracking */
      final InputLocation importedFrom;
  
      /**
        * Constructor for this class, to be called from its subclasses and {@link Builder}.
        * @see Builder#build()
        */
      protected Prerequisites(Builder builder) {
          this.maven = builder.maven != null ? builder.maven : (builder.base != null ? builder.base.maven : null);
          this.locations = builder.computeLocations();
          this.importedFrom = builder.importedFrom;
      }
  
      /**
       * For a plugin project (packaging is {@code maven-plugin}), the minimum version of
       * Maven required to use the resulting plugin.
       *
       * @return a {@code String}
       */
      public String getMaven() {
          return this.maven;
      }
  
      /**
       * Gets the location of the specified field in the input source.
       *
       * @param key the key of the field, must not be {@code null}
       * @return the location of the field in the input source or {@code null} if unknown
       * @throws NullPointerException if {@code key} is {@code null}
       */
      public InputLocation getLocation(Object key) {
          Objects.requireNonNull(key, "key");
          return locations.get(key);
      }
  
      /**
       * Gets the keys of the locations of the input source.
       */
      public Set<Object> getLocationKeys() {
          return locations.keySet();
      }
  
      protected Stream<Object> getLocationKeyStream() {
          return locations.keySet().stream();
      }
  
      /**
       * Gets the input location that caused this model to be read.
       */
      public InputLocation getImportedFrom() {
          return importedFrom;
      }
  
      /**
       * Creates a new builder with this object as the basis.
       *
       * @return a {@code Builder}
       */
      @Nonnull
      public Builder with() {
          return newBuilder(this);
      }
     /**
      * Creates a new {@code Prerequisites} instance using the specified maven.
      *
      * @param maven the new {@code String} to use
      * @return a {@code Prerequisites} with the specified maven
      */
     @Nonnull
     public Prerequisites withMaven(String maven) {
         return newBuilder(this, true).maven(maven).build();
     }
 
     /**
      * Creates a new {@code Prerequisites} instance.
      * Equivalent to {@code newInstance(true)}.
      * @see #newInstance(boolean)
      *
      * @return a new {@code Prerequisites}
      */
     @Nonnull
     public static Prerequisites newInstance() {
         return newInstance(true);
     }
 
     /**
      * Creates a new {@code Prerequisites} instance using default values or not.
      * Equivalent to {@code newBuilder(withDefaults).build()}.
      *
      * @param withDefaults the boolean indicating whether default values should be used
      * @return a new {@code Prerequisites}
      */
     @Nonnull
     public static Prerequisites newInstance(boolean withDefaults) {
         return newBuilder(withDefaults).build();
     }
 
     /**
      * Creates a new {@code Prerequisites} builder instance.
      * Equivalent to {@code newBuilder(true)}.
      * @see #newBuilder(boolean)
      *
      * @return a new {@code Builder}
      */
     @Nonnull
     public static Builder newBuilder() {
         return newBuilder(true);
     }
 
     /**
      * Creates a new {@code Prerequisites} builder instance using default values or not.
      *
      * @param withDefaults the boolean indicating whether default values should be used
      * @return a new {@code Builder}
      */
     @Nonnull
     public static Builder newBuilder(boolean withDefaults) {
         return new Builder(withDefaults);
     }
 
     /**
      * Creates a new {@code Prerequisites} builder instance using the specified object as a basis.
      * Equivalent to {@code newBuilder(from, false)}.
      *
      * @param from the {@code Prerequisites} instance to use as a basis
      * @return a new {@code Builder}
      */
     @Nonnull
     public static Builder newBuilder(Prerequisites from) {
         return newBuilder(from, false);
     }
 
     /**
      * Creates a new {@code Prerequisites} builder instance using the specified object as a basis.
      *
      * @param from the {@code Prerequisites} instance to use as a basis
      * @param forceCopy the boolean indicating if a copy should be forced
      * @return a new {@code Builder}
      */
     @Nonnull
     public static Builder newBuilder(Prerequisites from, boolean forceCopy) {
         return new Builder(from, forceCopy);
     }
 
     /**
      * Builder class used to create Prerequisites instances.
      * @see #with()
      * @see #newBuilder()
      */
     @NotThreadSafe
     public static class Builder
     {
         Prerequisites base;
         String maven;
         Map<Object, InputLocation> locations;
         InputLocation importedFrom;
 
         protected Builder(boolean withDefaults) {
             if (withDefaults) {
                 this.maven = "2.0";
             }
         }
 
         protected Builder(Prerequisites base, boolean forceCopy) {
             if (forceCopy) {
                 this.maven = base.maven;
                 this.locations = base.locations;
                 this.importedFrom = base.importedFrom;
             } else {
                 this.base = base;
             }
         }
 
         @Nonnull
         public Builder maven(String maven) {
             this.maven = maven;
             return this;
         }
 
 
         @Nonnull
         public Builder location(Object key, InputLocation location) {
             if (location != null) {
                 if (!(this.locations instanceof HashMap)) {
                     this.locations = this.locations != null ? new HashMap<>(this.locations) : new HashMap<>();
                 }
                 this.locations.put(key, location);
             }
             return this;
         }
 
         @Nonnull
         public Builder importedFrom(InputLocation importedFrom) {
             this.importedFrom = importedFrom;
             return this;
         }
 
         @Nonnull
         public Prerequisites build() {
             // this method should not contain any logic other than creating (or reusing) an object in order to ease subclassing
             if (base != null
                     && (maven == null || maven == base.maven)
             ) {
                 return base;
             }
             return new Prerequisites(this);
         }
 
         Map<Object, InputLocation> computeLocations() {
             Map<Object, InputLocation> newlocs = locations != null ? locations : Map.of();
             Map<Object, InputLocation> oldlocs = base != null ? base.locations : Map.of();
             if (newlocs.isEmpty()) {
                 return Map.copyOf(oldlocs);
             }
             if (oldlocs.isEmpty()) {
                 return Map.copyOf(newlocs);
             }
             return Stream.concat(newlocs.entrySet().stream(), oldlocs.entrySet().stream())
                     // Keep value from newlocs in case of duplicates
                     .collect(Collectors.toUnmodifiableMap(Map.Entry::getKey, Map.Entry::getValue, (v1, v2) -> v1));
         }
     }
 
 }