/*
    * 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.
   */
  package org.apache.commons.configuration2.builder.combined;
  
  import java.util.Map;
  
  import org.apache.commons.configuration2.ConfigurationUtils;
  import org.apache.commons.configuration2.builder.BasicBuilderParameters;
  import org.apache.commons.configuration2.builder.BuilderParameters;
  
  /**
   * <p>
   * A specialized parameters object for {@link MultiFileConfigurationBuilder}.
   * </p>
   * <p>
   * A parameters object of this type is used by a configuration builder with manages multiple file-based configurations.
   * Such a builder is a bit special because it does not create a configuration on its own, but delegates to a file-based
   * builder for this purpose. Therefore, parameters inherited from the super class are treated differently:
   * </p>
   * <ul>
   * <li>The {@link org.apache.commons.configuration2.interpol.ConfigurationInterpolator ConfigurationInterpolator} is
   * needed by a {@code MultiFileConfigurationBuilder} to resolve the file pattern. It is expected to be set and will not
   * be passed to sub configurations created by the builder.</li>
   * <li>All other parameters are evaluated when creating sub configurations. However, it is preferred to use the
   * {@link #setManagedBuilderParameters(BuilderParameters)} method to define all properties of sub configurations in a
   * single place. If such a parameters object is set, its properties take precedence.</li>
   * </ul>
   * <p>
   * This class is not thread-safe. It is intended that an instance is constructed and initialized by a single thread
   * during configuration of a {@code ConfigurationBuilder}.
   * </p>
   *
   * @since 2.0
   */
  public class MultiFileBuilderParametersImpl extends BasicBuilderParameters implements MultiFileBuilderProperties<MultiFileBuilderParametersImpl> {
      /** Constant for the key in the parameters map used by this class. */
      private static final String PARAM_KEY = RESERVED_PARAMETER_PREFIX + MultiFileBuilderParametersImpl.class.getName();
  
      /**
       * Obtains an instance of this class from the given map with parameters. If this map does not contain an instance,
       * result is <strong>null</strong>. This is equivalent to {@code fromParameters(params, false)}.
       *
       * @param params the map with parameters (must not be <strong>null</strong>)
       * @return an instance of this class fetched from the map or <strong>null</strong>
       * @throws NullPointerException if the map with parameters is <strong>null</strong>
       */
      public static MultiFileBuilderParametersImpl fromParameters(final Map<String, Object> params) {
          return fromParameters(params, false);
      }
  
      /**
       * Obtains an instance of this class from the given map with parameters and creates a new object if such an instance
       * cannot be found. This method can be used to obtain an instance from a map which has been created using the
       * {@code getParameters()} method. If the map does not contain an instance under the expected key and the
       * {@code createIfMissing} parameter is <strong>true</strong>, a new instance is created. Otherwise, result is <strong>null</strong>.
       *
       * @param params the map with parameters (must not be <strong>null</strong>)
       * @param createIfMissing a flag whether a new instance should be created if necessary
       * @return an instance of this class fetched from the map or <strong>null</strong>
       * @throws NullPointerException if the map with parameters is <strong>null</strong>
       */
      public static MultiFileBuilderParametersImpl fromParameters(final Map<String, Object> params, final boolean createIfMissing) {
          MultiFileBuilderParametersImpl instance = (MultiFileBuilderParametersImpl) params.get(PARAM_KEY);
          if (instance == null && createIfMissing) {
              instance = new MultiFileBuilderParametersImpl();
          }
          return instance;
      }
  
      /** The parameters object for managed builders. */
      private BuilderParameters managedBuilderParameters;
  
      /** The file pattern. */
      private String filePattern;
  
      /**
       * {@inheritDoc} This implementation also tries to clone the parameters object for managed builders if possible.
       */
      @Override
      public MultiFileBuilderParametersImpl clone() {
          final MultiFileBuilderParametersImpl copy = (MultiFileBuilderParametersImpl) super.clone();
          copy.setManagedBuilderParameters((BuilderParameters) ConfigurationUtils.cloneIfPossible(getManagedBuilderParameters()));
          return copy;
      }
  
     /**
      * Gets the pattern for determining file names for managed configurations.
      *
      * @return the file pattern
      */
     public String getFilePattern() {
         return filePattern;
     }
 
     /**
      * Gets the parameters object for managed configuration builders.
      *
      * @return the parameters for sub configurations
      */
     public BuilderParameters getManagedBuilderParameters() {
         return managedBuilderParameters;
     }
 
     /**
      * {@inheritDoc} This implementation puts a reference to this object under a reserved key in the resulting parameters
      * map.
      */
     @Override
     public Map<String, Object> getParameters() {
         final Map<String, Object> params = super.getParameters();
         params.put(PARAM_KEY, this);
         return params;
     }
 
     @Override
     public MultiFileBuilderParametersImpl setFilePattern(final String p) {
         filePattern = p;
         return this;
     }
 
     @Override
     public MultiFileBuilderParametersImpl setManagedBuilderParameters(final BuilderParameters p) {
         managedBuilderParameters = p;
         return this;
     }
 }