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.celeborn.reflect;
  
  import java.util.LinkedHashSet;
  import java.util.Set;
  
  /** this class is copied from Apache Kyuubi, derived from iceberg-common */
  public class DynClasses {
  
    private DynClasses() {}
  
    public static Builder builder() {
      return new Builder();
    }
  
    public static class Builder {
      private ClassLoader loader = Thread.currentThread().getContextClassLoader();
      private Class<?> foundClass = null;
      private boolean nullOk = false;
      private final Set<String> classNames = new LinkedHashSet<>();
  
      private Builder() {}
  
      /**
       * Set the {@link ClassLoader} used to lookup classes by name.
       *
       * <p>If not set, the current thread's ClassLoader is used.
       *
       * @param newLoader a ClassLoader
       * @return this Builder for method chaining
       */
      public Builder loader(ClassLoader newLoader) {
        this.loader = newLoader;
        return this;
      }
  
      /**
       * Checks for an implementation of the class by name.
       *
       * @param className name of a class
       * @return this Builder for method chaining
       */
      public Builder impl(String className) {
        classNames.add(className);
  
        if (foundClass != null) {
          return this;
        }
  
        try {
          this.foundClass = Class.forName(className, true, loader);
        } catch (ClassNotFoundException e) {
          // not the right implementation
        }
  
        return this;
      }
  
      /**
       * Instructs this builder to return null if no class is found, rather than throwing an
       * Exception.
       *
       * @return this Builder for method chaining
       */
      public Builder orNull() {
        this.nullOk = true;
        return this;
      }
  
      /**
       * Returns the first implementation or throws ClassNotFoundException if one was not found.
       *
       * @param <S> Java superclass
       * @return a {@link Class} for the first implementation found
       * @throws ClassNotFoundException if no implementation was found
       */
      @SuppressWarnings("unchecked")
      public <S> Class<? extends S> buildChecked() throws ClassNotFoundException {
        if (!nullOk && foundClass == null) {
          throw new ClassNotFoundException(
              "Cannot find class; alternatives: " + String.join(", ", classNames));
        }
        return (Class<? extends S>) foundClass;
      }
  
      /**
       * Returns the first implementation or throws RuntimeException if one was not found.
       *
       * @param <S> Java superclass
       * @return a {@link Class} for the first implementation found
       * @throws RuntimeException if no implementation was found
       */
      @SuppressWarnings("unchecked")
      public <S> Class<? extends S> build() {
        if (!nullOk && foundClass == null) {
          throw new RuntimeException(
              "Cannot find class; alternatives: " + String.join(", ", classNames));
        }
        return (Class<? extends S>) foundClass;
      }
    }
  }
  