1 /* 2 * Copyright (C) 2021 The Android Open Source Project 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 com.android.server.wm.traces.common 18 19 /** 20 * The utility class to wait a condition with customized options. 21 * The default retry policy is 5 times with interval 1 second. 22 * 23 * @param <T> The type of the object to validate. 24 * 25 * <p>Sample:</p> 26 * <pre> 27 * // Simple case. 28 * if (Condition.waitFor("true value", () -> true)) { 29 * println("Success"); 30 * } 31 * // Wait for customized result with customized validation. 32 * String result = Condition.waitForResult(new Condition<String>("string comparison") 33 * .setResultSupplier(() -> "Result string") 34 * .setResultValidator(str -> str.equals("Expected string")) 35 * .setRetryIntervalMs(500) 36 * .setRetryLimit(3) 37 * .setOnFailure(str -> println("Failed on " + str))); 38 * </pre> 39 40 * @param message The message to show what is waiting for. 41 * @param condition If it returns true, that means the condition is satisfied. 42 */ 43 open class Condition<T>( 44 protected open val message: String = "", 45 protected open val condition: (T) -> Boolean 46 ) { 47 /** 48 * @return if [value] satisfies the condition 49 */ isSatisfiednull50 fun isSatisfied(value: T): Boolean { 51 return condition.invoke(value) 52 } 53 54 /** 55 * @return the negation of the current assertion 56 */ negatenull57 fun negate(): Condition<T> = Condition( 58 message = "!$message") { 59 !this.condition.invoke(it) 60 } 61 62 /** 63 * @return a formatted message for the passing or failing condition on a state 64 */ getMessagenull65 open fun getMessage(value: T): String = "$message(passed=${isSatisfied(value)})" 66 67 override fun toString(): String = this.message 68 }