1 /* 2 * Copyright (C) 2013 DroidDriver committers 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.appium.droiddriver.finders; 18 19 import io.appium.droiddriver.UiElement; 20 import io.appium.droiddriver.util.Preconditions; 21 22 /** 23 * Finds UiElement by applying Finders in turn: using the UiElement returned by 24 * first Finder as context for the second Finder. It is conceptually similar to 25 * <a href="http://en.wikipedia.org/wiki/Functional_composition">Function 26 * composition</a>. The returned UiElement can be thought of as the result of 27 * second(first(context)). 28 * <p> 29 * Note typically first Finder finds the ancestor, then second Finder finds the 30 * target UiElement, which is a descendant. ChainFinder can be chained with 31 * additional Finders to make a "chain". 32 */ 33 public class ChainFinder implements Finder { 34 private final Finder first; 35 private final Finder second; 36 37 protected ChainFinder(Finder first, Finder second) { 38 this.first = Preconditions.checkNotNull(first); 39 this.second = Preconditions.checkNotNull(second); 40 } 41 42 @Override 43 public String toString() { 44 return String.format("Chain{%s, %s}", first, second); 45 } 46 47 @Override 48 public UiElement find(UiElement context) { 49 return second.find(first.find(context)); 50 } 51 } 52
