package org.eclipse.aether.internal.impl.synccontext.named;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import org.eclipse.aether.named.NamedLockFactory;
  
  import java.util.Map;
  
  /**
   * Selector implementation support class: by extending this class one may override defaults, or provide completely
   * alternative way of configuration. This implementation uses Java System properties to select factory and name mapper.
   *
   * @since 1.7.3
   */
  public abstract class NamedLockFactorySelectorSupport
      implements NamedLockFactorySelector
  {
      public static final String FACTORY_KEY = "aether.syncContext.named.factory";
  
      public static final String NAME_MAPPER_KEY = "aether.syncContext.named.nameMapper";
  
      private final NamedLockFactory namedLockFactory;
  
      private final NameMapper nameMapper;
  
      public NamedLockFactorySelectorSupport( final Map<String, NamedLockFactory> factories,
                                              final String defaultFactoryName,
                                              final Map<String, NameMapper> nameMappers,
                                              final String defaultNameMapperName )
      {
          this.namedLockFactory = selectNamedLockFactory( factories, getFactoryName( defaultFactoryName ) );
          this.nameMapper = selectNameMapper( nameMappers, getNameMapperName( defaultNameMapperName ) );
      }
  
      /**
       * Returns the selected {@link NamedLockFactory}, never null.
       */
      @Override
      public NamedLockFactory getSelectedNamedLockFactory()
      {
          return namedLockFactory;
      }
  
      /**
       * Returns the selected {@link NameMapper}, never null.
       */
      @Override
      public NameMapper getSelectedNameMapper()
      {
          return nameMapper;
      }
  
      /**
       * Returns selected factory name (or passed in default) using System property value of {@link #FACTORY_KEY}.
       */
      protected String getFactoryName( final String defaultFactoryName )
      {
          return System.getProperty( FACTORY_KEY, defaultFactoryName );
      }
  
      /**
       * Returns selected name mapper name (or passed in default) using System property value of {@link #NAME_MAPPER_KEY}.
       */
      protected String getNameMapperName( final String defaultNameMapperName )
      {
          return System.getProperty( NAME_MAPPER_KEY, defaultNameMapperName );
      }
  
      private NamedLockFactory selectNamedLockFactory( final Map<String, NamedLockFactory> factories,
                                                       final String factoryName )
      {
          NamedLockFactory factory = factories.get( factoryName );
          if ( factory == null )
          {
              throw new IllegalArgumentException( "Unknown NamedLockFactory name: " + factoryName
                  + ", known ones: " + factories.keySet() );
          }
          return factory;
      }
  
      private NameMapper selectNameMapper( final Map<String, NameMapper> nameMappers,
                                           final String mapperName )
     {
         NameMapper nameMapper = nameMappers.get( mapperName );
         if ( nameMapper == null )
         {
             throw new IllegalArgumentException( "Unknown NameMapper name: " + mapperName
                 + ", known ones: " + nameMappers.keySet() );
         }
         return nameMapper;
     }
 }