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;
  
  import java.util.Set;
  
  /**
   * Some implementations of WebDriver, notably those that support native testing, need the ability to
   * switch between the native and web-based contexts. This can be achieved by using this interface.
   */
  public interface ContextAware {
  
    /**
     * Switch the focus of future commands for this driver to the context with the given name.
     *
     * @param name The name of the context as returned by {@link #getContextHandles()}.
     * @return This driver focused on the given window.
     * @throws NoSuchContextException If the context cannot be found.
     */
    WebDriver context(String name);
  
    /**
     * Return a set of context handles which can be used to iterate over all contexts of this
     * WebDriver instance.
     *
     * @return A set of context handles which can be used to iterate over available contexts.
     */
    Set<String> getContextHandles();
  
    /**
     * Return an opaque handle to this context that uniquely identifies it within this driver
     * instance. This can be used to switch to this context at a later date.
     *
     * @return The current context handle.
     */
    String getContext();
  }
  