jtulach@315: package org.apidesign.javamonitorflaws;
jtulach@315: 
jtulach@315: import java.beans.PropertyChangeEvent;
jtulach@315: import java.beans.PropertyChangeListener;
jtulach@315: import org.netbeans.junit.NbTestCase;
jtulach@315: 
jtulach@315: public class CacheTest extends NbTestCase {
jtulach@315:     public CacheTest(String n) {
jtulach@315:         super(n);
jtulach@315:     }
jtulach@315: 
jtulach@315:     @Override
jtulach@315:     protected int timeOut() {
jtulach@315:         return 2000;
jtulach@315:     }
jtulach@315: 
jtulach@315:     /**
jtulach@315:      * To simulate deadlock between the cache's setMultiply method and
jtulach@315:      * ToDeadlock's own lock. The root cause is that setMultiply is calling
jtulach@315:      * foreign code while holding the caches's <code>this</code> lock:
jtulach@315:      
jtulach@315: Thread Test Watch Dog: testDeadlockWithSetter
jtulach@315:   org.apidesign.javamonitorflaws.MultiplyCache.setMultiply:19
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$1ToDeadlock.assertMultiplyByTen:40
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest.testDeadlockWithSetter:50
jtulach@315:   sun.reflect.NativeMethodAccessorImpl.invoke0:-2
jtulach@315:   sun.reflect.NativeMethodAccessorImpl.invoke:39
jtulach@315:   sun.reflect.DelegatingMethodAccessorImpl.invoke:25
jtulach@315:   java.lang.reflect.Method.invoke:597
jtulach@315:   junit.framework.TestCase.runTest:168
jtulach@315:   org.netbeans.junit.NbTestCase.access$200:84
jtulach@315:   org.netbeans.junit.NbTestCase$2.doSomething:328
jtulach@315:   org.netbeans.junit.NbTestCase$1Guard.run:265
jtulach@315:   java.lang.Thread.run:619
jtulach@315: Thread to deadlock
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$1ToDeadlock.assertMultiplyByTen:40
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$1ToDeadlock.propertyChange:36
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:339
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:276
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:297
jtulach@315:   org.apidesign.javamonitorflaws.MultiplyCache.setMultiply:21
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$1ToDeadlock.run:28
jtulach@315:   java.lang.Thread.run:619
jtulach@315:      
jtulach@315:      */
jtulach@315:     public void testDeadlockWithSetter() throws Exception {
jtulach@315:         if (Boolean.getBoolean("no.failures")) return;
jtulach@315:         
jtulach@319:         final CacheToTest cache = new MultiplyCache();
jtulach@319: 
jtulach@315:         class ToDeadlock implements Runnable, PropertyChangeListener {
jtulach@315:             int value;
jtulach@315: 
jtulach@315:             public void run() {
jtulach@315:                 cache.setMultiply(10);
jtulach@315:             }
jtulach@315:             public void propertyChange(PropertyChangeEvent evt) {
jtulach@315:                 try {
jtulach@315:                     Thread.sleep(500);
jtulach@315:                 } catch (InterruptedException ex) {
jtulach@315:                     // ok
jtulach@315:                 }
jtulach@315:                 changeMultiplyToSeven();
jtulach@315:             }
jtulach@315: 
jtulach@315:             public synchronized void changeMultiplyToSeven() {
jtulach@315:                 cache.setMultiply(7);
jtulach@315:             }
jtulach@315:         }
jtulach@315:         ToDeadlock toDeadlock = new ToDeadlock();
jtulach@315:         cache.addPropertyChangeListener(toDeadlock);
jtulach@315:         Thread t = new Thread(toDeadlock, "to deadlock");
jtulach@315:         t.start();
jtulach@315: 
jtulach@315:         Thread.sleep(100);
jtulach@315: 
jtulach@315:         toDeadlock.changeMultiplyToSeven();
jtulach@315:     }
jtulach@315: 
jtulach@315:     /** Shows that one can deadlock with the cache's API even the API
jtulach@315:      * is locally correctly synchronized.
jtulach@315: Thread Test Watch Dog: testDeadlockWithTheAPICacheItself
jtulach@315:   org.apidesign.javamonitorflaws.Cache.get:16
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$2ToDeadlock.assertMultiplyByTen
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest.testDeadlockViaAPI:112
jtulach@315:   java.lang.reflect.Method.invoke:597
jtulach@315:   org.netbeans.junit.NbTestCase.access$200:84
jtulach@315:   org.netbeans.junit.NbTestCase$2.doSomething:328
jtulach@315:   org.netbeans.junit.NbTestCase$1Guard.run:265
jtulach@315:   java.lang.Thread.run:619
jtulach@315: Thread Deadlock using API
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$2ToDeadlock.assertMultiplyByTen
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$2ToDeadlock.propertyChange:98
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:339
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:276
jtulach@315:   java.beans.PropertyChangeSupport.firePropertyChange:297
jtulach@315:   org.apidesign.javamonitorflaws.MultiplyCache.setMultiply:21
jtulach@315:   org.apidesign.javamonitorflaws.CacheTest$2ToDeadlock.run:90
jtulach@315:   java.lang.Thread.run:619
jtulach@315:      */
jtulach@315:     public void testDeadlockViaAPI() throws Exception {
jtulach@315:         if (Boolean.getBoolean("no.failures")) return;
jtulach@319:         testDeadlockViaAPI(new MultiplyCache());
jtulach@319:     }
jtulach@319: 
jtulach@319:     // BEGIN: monitor.pitfalls.block.propertychange
jtulach@319:     private static void testDeadlockViaAPI(final CacheToTest cache)
jtulach@319:     throws Exception {
jtulach@315:         class ToDeadlock implements Runnable, PropertyChangeListener {
jtulach@317:             int lastMultiply;
jtulach@317: 
jtulach@315:             public void run() {
jtulach@315:                 cache.setMultiply(10);
jtulach@315:             }
jtulach@315:             public void propertyChange(PropertyChangeEvent evt) {
jtulach@315:                 try {
jtulach@317:                     storeMultiply();
jtulach@315:                 } catch (InterruptedException ex) {
jtulach@315:                     // ok
jtulach@315:                 }
jtulach@315:             }
jtulach@315: 
jtulach@317:             private synchronized void storeMultiply()
jtulach@317:             throws InterruptedException {
jtulach@317:                 lastMultiply = cache.getMultiply();
jtulach@317:                 // simulates "starvation"
jtulach@317:                 wait();
jtulach@317:             }
jtulach@317: 
jtulach@317:             public void assertMultiplyByTen() {
jtulach@315:             }
jtulach@315:         }
jtulach@315:         ToDeadlock toDeadlock = new ToDeadlock();
jtulach@315:         cache.addPropertyChangeListener(toDeadlock);
jtulach@315:         Thread t = new Thread(toDeadlock, "Deadlock using API");
jtulach@315:         t.start();
jtulach@315: 
jtulach@315:         Thread.sleep(100);
jtulach@315: 
jtulach@317:         // BEGIN: monitor.pitfalls.brokencall
jtulach@317:         int value =  cache.get("123");
jtulach@317:         assertEquals("3*10=30", 30, value);
jtulach@317:         // END: monitor.pitfalls.brokencall
jtulach@315:     }
jtulach@317:     // END: monitor.pitfalls.block.propertychange
jtulach@319: 
jtulach@319:     public void testDeadlockViaAPIWithCacheOK() throws Exception {
jtulach@319:         testDeadlockViaAPI(new MultiplyCacheOK());
jtulach@319:     }
jtulach@319: 
jtulach@319:     static interface CacheToTest {
jtulach@319:         public Integer get(String key);
jtulach@319: 
jtulach@319:         public void setMultiply(int m);
jtulach@319:         public int getMultiply();
jtulach@319:         public void addPropertyChangeListener(PropertyChangeListener l);
jtulach@319:         public void removePropertyChangeListener(PropertyChangeListener l);
jtulach@319:     }
jtulach@315: }