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.apache.calcite.linq4j.function.Predicate1;
  import org.apache.calcite.util.NameMap;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Map;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  /**
   * A Lookup class which is based on a NameMap.
   *
   * @param <T> Element type
   */
  class NameMapLookup<T> implements Lookup<T> {
    private final NameMap<T> map;
  
    NameMapLookup(NameMap<T> map) {
      this.map = map;
    }
  
    @Override public @Nullable T get(String name) {
      Map.Entry<String, T> entry = map.range(name, true).firstEntry();
      if (entry != null) {
        return entry.getValue();
      }
      return null;
    }
  
    @Override public @Nullable Named<T> getIgnoreCase(String name) {
      Map.Entry<String, T> entry = map.range(name, false).firstEntry();
      if (entry != null) {
        return new Named<>(entry.getKey(), entry.getValue());
      }
      return null;
    }
  
    @Override public Set<String> getNames(LikePattern pattern) {
      final Predicate1<String> matcher = pattern.matcher();
      return map.map().keySet().stream()
          .filter(name -> matcher.apply(name))
          .collect(Collectors.toSet());
    }
  }
  