1 /* 2 * Copyright (C) 2009 The Guava Authors 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.google.common.util.concurrent; 18 19 import com.google.common.base.Supplier; 20 import com.google.common.base.Suppliers; 21 22 import junit.framework.TestCase; 23 24 import java.security.Permission; 25 import java.util.concurrent.Callable; 26 27 /** 28 * Unit tests for {@link Callables}. 29 * 30 * @author Isaac Shum 31 */ 32 public class CallablesTest extends TestCase { 33 testReturning()34 public void testReturning() throws Exception { 35 assertNull(Callables.returning(null).call()); 36 37 Object value = new Object(); 38 Callable<Object> callable = Callables.returning(value); 39 assertSame(value, callable.call()); 40 // Expect the same value on subsequent calls 41 assertSame(value, callable.call()); 42 } 43 testRenaming()44 public void testRenaming() throws Exception { 45 String oldName = Thread.currentThread().getName(); 46 final Supplier<String> newName = Suppliers.ofInstance("MyCrazyThreadName"); 47 Callable<Void> callable = new Callable<Void>() { 48 @Override public Void call() throws Exception { 49 assertEquals(Thread.currentThread().getName(), newName.get()); 50 return null; 51 } 52 }; 53 Callables.threadRenaming(callable, newName).call(); 54 assertEquals(oldName, Thread.currentThread().getName()); 55 } 56 testRenaming_exceptionalReturn()57 public void testRenaming_exceptionalReturn() throws Exception { 58 String oldName = Thread.currentThread().getName(); 59 final Supplier<String> newName = Suppliers.ofInstance("MyCrazyThreadName"); 60 class MyException extends Exception {} 61 Callable<Void> callable = new Callable<Void>() { 62 @Override public Void call() throws Exception { 63 assertEquals(Thread.currentThread().getName(), newName.get()); 64 throw new MyException(); 65 } 66 }; 67 try { 68 Callables.threadRenaming(callable, newName).call(); 69 fail(); 70 } catch (MyException expected) {} 71 assertEquals(oldName, Thread.currentThread().getName()); 72 } 73 testRenaming_noPermissions()74 public void testRenaming_noPermissions() throws Exception { 75 System.setSecurityManager(new SecurityManager() { 76 @Override public void checkAccess(Thread t) { 77 throw new SecurityException(); 78 } 79 @Override public void checkPermission(Permission perm) { 80 // Do nothing so we can clear the security manager at the end 81 } 82 }); 83 try { 84 final String oldName = Thread.currentThread().getName(); 85 Supplier<String> newName = Suppliers.ofInstance("MyCrazyThreadName"); 86 Callable<Void> callable = new Callable<Void>() { 87 @Override public Void call() throws Exception { 88 assertEquals(Thread.currentThread().getName(), oldName); 89 return null; 90 } 91 }; 92 Callables.threadRenaming(callable, newName).call(); 93 assertEquals(oldName, Thread.currentThread().getName()); 94 } finally { 95 System.setSecurityManager(null); 96 } 97 } 98 } 99