content: /*
   * Copyright (C) 2021 The Android Open Source Project
   *
   * Licensed 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 androidx.test.internal.platform.reflect;
  
  import androidx.annotation.RestrictTo;
  import androidx.annotation.RestrictTo.Scope;
  import java.lang.reflect.Field;
  
  /**
   * Helper class for making more performant reflection field access.
   *
   * <p>Lazy initializes and caches Method object ro attempt to reduce reflection overhead.
   *
   * @hide
   */
  @RestrictTo(Scope.LIBRARY_GROUP)
  public class ReflectiveField<T> {
    private final String className;
    private final String fieldName;
    private final Class<?> clazz;
  
    // lazy init
    private boolean initialized = false;
    private Field field;
  
    /**
     * Creates a ReflectiveField.
     *
     * @param className the fully qualified class name that defines the field
     * @param fieldName the field name
     */
    public ReflectiveField(String className, String fieldName) {
      this.clazz = null;
      this.className = className;
      this.fieldName = fieldName;
    }
  
    public ReflectiveField(Class<?> clazz, String fieldName) {
      this.clazz = clazz;
      this.className = null;
      this.fieldName = fieldName;
    }
  
    /**
     * Retrieves the field's value, initializing if necessary.
     *
     * @param object the object that holds the field's value
     * @return the field's value
     * @throws ReflectionException if field could not be accessed
     */
    public T get(Object object) throws ReflectionException {
      try {
        initIfNecessary();
        return (T) field.get(object);
      } catch (ClassNotFoundException e) {
        throw new ReflectionException(e);
      } catch (NoSuchFieldException e) {
        throw new ReflectionException(e);
      } catch (IllegalAccessException e) {
        throw new ReflectionException(e);
      }
    }
  
    private synchronized void initIfNecessary() throws ClassNotFoundException, NoSuchFieldException {
      if (initialized) {
        return;
      }
      field = getClazz().getDeclaredField(fieldName);
      field.setAccessible(true);
      initialized = true;
    }
  
    private Class<?> getClazz() throws ClassNotFoundException {
      if (clazz == null) {
        return Class.forName(className);
      } else {
        return clazz;
      }
    }
  }
  