1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/samples/deadlock/src/org/apidesign/javamonitorflaws/CacheOK.java	Thu Feb 12 10:55:02 2009 +0100
     1.3 @@ -0,0 +1,54 @@
     1.4 +package org.apidesign.javamonitorflaws;
     1.5 +
     1.6 +import java.util.HashMap;
     1.7 +import java.util.Map;
     1.8 +
     1.9 +/** Classical caching support class that makes sure there is
    1.10 + * always one "To" value for each "From" one returned from the {@link #get}
    1.11 + * method. However it does not prevent multiple threads to call
    1.12 + * {@link #createItem} multiple times for the same "From" value.
    1.13 + * <p>
    1.14 + * In contrast to {@link Cache}, this is correctly synchronized.
    1.15 + *
    1.16 + * @author Jaroslav Tulach <jtulach@netbeans.org>
    1.17 + */
    1.18 +// BEGIN: monitor.pitfalls.CacheOK
    1.19 +public abstract class CacheOK<From,To> {
    1.20 +    private Object LOCK = new Object();
    1.21 +
    1.22 +    private Map<From,To> cache;
    1.23 +
    1.24 +    protected abstract To createItem(From f);
    1.25 +
    1.26 +    public final To get(From f) {
    1.27 +        To t = inspectValue(f);
    1.28 +        if (t != null) {
    1.29 +            return t;
    1.30 +        }
    1.31 +        To newT = createItem(f);
    1.32 +        return registerValue(f, newT);
    1.33 +    }
    1.34 +
    1.35 +
    1.36 +    private To inspectValue(From f) {
    1.37 +        synchronized (LOCK) {
    1.38 +            if (cache == null) {
    1.39 +                cache = new HashMap<From, To>();
    1.40 +            }
    1.41 +            return cache.get(f);
    1.42 +        }
    1.43 +    }
    1.44 +
    1.45 +    private To registerValue(From f, To newT) {
    1.46 +        synchronized (LOCK) {
    1.47 +            To t = cache.get(f);
    1.48 +            if (t == null) {
    1.49 +                cache.put(f, newT);
    1.50 +                return newT;
    1.51 +            } else {
    1.52 +                return t;
    1.53 +            }
    1.54 +        }
    1.55 +    }
    1.56 +}
    1.57 +// END: monitor.pitfalls.CacheOK

     2.1 --- a/samples/deadlock/test/org/apidesign/javamonitorflaws/CacheTest.java	Wed Feb 11 10:16:43 2009 +0100
     2.2 +++ b/samples/deadlock/test/org/apidesign/javamonitorflaws/CacheTest.java	Thu Feb 12 10:55:02 2009 +0100
     2.3 @@ -5,8 +5,6 @@
     2.4  import org.netbeans.junit.NbTestCase;
     2.5  
     2.6  public class CacheTest extends NbTestCase {
     2.7 -    private MultiplyCache cache = new MultiplyCache();
     2.8 -
     2.9      public CacheTest(String n) {
    2.10          super(n);
    2.11      }
    2.12 @@ -48,6 +46,8 @@
    2.13      public void testDeadlockWithSetter() throws Exception {
    2.14          if (Boolean.getBoolean("no.failures")) return;
    2.15          
    2.16 +        final CacheToTest cache = new MultiplyCache();
    2.17 +
    2.18          class ToDeadlock implements Runnable, PropertyChangeListener {
    2.19              int value;
    2.20  
    2.21 @@ -98,10 +98,14 @@
    2.22    org.apidesign.javamonitorflaws.CacheTest$2ToDeadlock.run:90
    2.23    java.lang.Thread.run:619
    2.24       */
    2.25 -    // BEGIN: monitor.pitfalls.block.propertychange
    2.26      public void testDeadlockViaAPI() throws Exception {
    2.27          if (Boolean.getBoolean("no.failures")) return;
    2.28 -        
    2.29 +        testDeadlockViaAPI(new MultiplyCache());
    2.30 +    }
    2.31 +
    2.32 +    // BEGIN: monitor.pitfalls.block.propertychange
    2.33 +    private static void testDeadlockViaAPI(final CacheToTest cache)
    2.34 +    throws Exception {
    2.35          class ToDeadlock implements Runnable, PropertyChangeListener {
    2.36              int lastMultiply;
    2.37  
    2.38 @@ -139,4 +143,17 @@
    2.39          // END: monitor.pitfalls.brokencall
    2.40      }
    2.41      // END: monitor.pitfalls.block.propertychange
    2.42 +
    2.43 +    public void testDeadlockViaAPIWithCacheOK() throws Exception {
    2.44 +        testDeadlockViaAPI(new MultiplyCacheOK());
    2.45 +    }
    2.46 +
    2.47 +    static interface CacheToTest {
    2.48 +        public Integer get(String key);
    2.49 +
    2.50 +        public void setMultiply(int m);
    2.51 +        public int getMultiply();
    2.52 +        public void addPropertyChangeListener(PropertyChangeListener l);
    2.53 +        public void removePropertyChangeListener(PropertyChangeListener l);
    2.54 +    }
    2.55  }
    2.56 \ No newline at end of file

     3.1 --- a/samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCache.java	Wed Feb 11 10:16:43 2009 +0100
     3.2 +++ b/samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCache.java	Thu Feb 12 10:55:02 2009 +0100
     3.3 @@ -1,6 +1,5 @@
     3.4  package org.apidesign.javamonitorflaws;
     3.5  
     3.6 -import org.apidesign.javamonitorflaws.Cache;
     3.7  import java.beans.PropertyChangeListener;
     3.8  import java.beans.PropertyChangeSupport;
     3.9  
    3.10 @@ -9,7 +8,8 @@
    3.11   * @author Jaroslav Tulach <jtulach@netbeans.org>
    3.12   */
    3.13  // BEGIN: monitor.pitfalls.subclass
    3.14 -public class MultiplyCache extends Cache<String,Integer> {
    3.15 +public class MultiplyCache extends Cache<String,Integer>
    3.16 +implements CacheTest.CacheToTest {
    3.17      private PropertyChangeSupport pcs;
    3.18      private int multiply;
    3.19      public static final String PROP_MULTIPLY = "multiply";
    3.20 @@ -41,7 +41,7 @@
    3.21  
    3.22      @Override
    3.23      protected Integer createItem(String f) {
    3.24 -        return f.length() * getMultiply();
    3.25 +        return f.length() * multiply;
    3.26      }
    3.27  }
    3.28  // END: monitor.pitfalls.subclass

     4.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     4.2 +++ b/samples/deadlock/test/org/apidesign/javamonitorflaws/MultiplyCacheOK.java	Thu Feb 12 10:55:02 2009 +0100
     4.3 @@ -0,0 +1,49 @@
     4.4 +package org.apidesign.javamonitorflaws;
     4.5 +
     4.6 +import java.beans.PropertyChangeListener;
     4.7 +import java.beans.PropertyChangeSupport;
     4.8 +
     4.9 +/**
    4.10 + *
    4.11 + * @author Jaroslav Tulach <jtulach@netbeans.org>
    4.12 + */
    4.13 +// BEGIN: monitor.pitfalls.subclassok
    4.14 +public class MultiplyCacheOK extends CacheOK<String,Integer>
    4.15 +implements CacheTest.CacheToTest {
    4.16 +    private PropertyChangeSupport pcs;
    4.17 +    private int multiply;
    4.18 +    public static final String PROP_MULTIPLY = "multiply";
    4.19 +
    4.20 +    public synchronized int getMultiply() {
    4.21 +        return multiply;
    4.22 +    }
    4.23 +    public synchronized void setMultiply(int multiply) {
    4.24 +        int oldMultiply = this.multiply;
    4.25 +        this.multiply = multiply;
    4.26 +        pcs.firePropertyChange(PROP_MULTIPLY, oldMultiply, multiply);
    4.27 +    }
    4.28 +
    4.29 +    public synchronized void addPropertyChangeListener(
    4.30 +        PropertyChangeListener listener
    4.31 +    ) {
    4.32 +        if (pcs == null) {
    4.33 +            pcs = new PropertyChangeSupport(this);
    4.34 +        }
    4.35 +        pcs.addPropertyChangeListener(listener);
    4.36 +    }
    4.37 +    public synchronized void removePropertyChangeListener(
    4.38 +        PropertyChangeListener listener
    4.39 +    ) {
    4.40 +        if (pcs != null) {
    4.41 +            pcs.removePropertyChangeListener(listener);
    4.42 +        }
    4.43 +    }
    4.44 +
    4.45 +    @Override
    4.46 +    protected Integer createItem(String f) {
    4.47 +        return f.length() * multiply;
    4.48 +    }
    4.49 +}
    4.50 +// END: monitor.pitfalls.subclassok
    4.51 +
    4.52 +