content: /*
   * 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.calcite.schema.lookup;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Set;
  import java.util.function.BiFunction;
  
  /**
   * This class implements a {@code Lookup} on base of another {@code Lookup}
   * transforming all entities using a given function.
   *
   * @param <S> Source element type
   * @param <T> Target element type
   */
  class TransformingLookup<S, T> implements Lookup<T> {
    private final Lookup<S> lookup;
    private final BiFunction<S, String, T> transform;
  
    TransformingLookup(Lookup<S> lookup, BiFunction<S, String, T> transform) {
      this.lookup = lookup;
      this.transform = transform;
    }
  
    @Override public @Nullable T get(String name) {
      S entity = lookup.get(name);
      return entity == null ? null : transform.apply(entity, name);
    }
  
    @Override public @Nullable Named<T> getIgnoreCase(String name) {
      Named<S> named = lookup.getIgnoreCase(name);
      return named == null
          ? null
          : new Named<>(named.name(), transform.apply(named.entity(), named.name()));
    }
  
    @Override public Set<String> getNames(LikePattern pattern) {
      return lookup.getNames(pattern);
    }
  }
  