code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC 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.openqa.selenium.support.pagefactory;
  
  import java.lang.reflect.Field;
  import java.util.List;
  import org.openqa.selenium.By;
  import org.openqa.selenium.SearchContext;
  import org.openqa.selenium.WebElement;
  
  /**
   * The default element locator, which will lazily locate an element or an element list on a page.
   * This class is designed for use with the {@link org.openqa.selenium.support.PageFactory} and
   * understands the annotations {@link org.openqa.selenium.support.FindBy} and {@link
   * org.openqa.selenium.support.CacheLookup}.
   */
  public class DefaultElementLocator implements ElementLocator {
    private final SearchContext searchContext;
    private final boolean shouldCache;
    private final By by;
    private WebElement cachedElement;
    private List<WebElement> cachedElementList;
  
    /**
     * Creates a new element locator.
     *
     * @param searchContext The context to use when finding the element
     * @param field The field on the Page Object that will hold the located value
     */
    public DefaultElementLocator(SearchContext searchContext, Field field) {
      this(searchContext, new Annotations(field));
    }
  
    /**
     * Use this constructor in order to process custom annotations.
     *
     * @param searchContext The context to use when finding the element
     * @param annotations AbstractAnnotations class implementation
     */
    public DefaultElementLocator(SearchContext searchContext, AbstractAnnotations annotations) {
      this.searchContext = searchContext;
      this.shouldCache = annotations.isLookupCached();
      this.by = annotations.buildBy();
    }
  
    /** Find the element. */
    @Override
    public WebElement findElement() {
      if (cachedElement != null && shouldCache()) {
        return cachedElement;
      }
  
      WebElement element = searchContext.findElement(by);
      if (shouldCache()) {
        cachedElement = element;
      }
  
      return element;
    }
  
    /** Find the element list. */
    @Override
    public List<WebElement> findElements() {
      if (cachedElementList != null && shouldCache()) {
        return cachedElementList;
      }
  
      List<WebElement> elements = searchContext.findElements(by);
      if (shouldCache()) {
        cachedElementList = elements;
      }
  
      return elements;
    }
  
    /**
     * Returns whether the element should be cached.
     *
     * @return {@code true} if the element should be cached
     */
    protected boolean shouldCache() {
      return shouldCache;
    }
  
    @Override
    public String toString() {
      return this.getClass().getSimpleName() + " '" + by + "'";
    }
  }
  