Migrated attachment for Guice issue 354, comment 1

354.patch

Index: src/com/google/inject/spi/CachedValue.java
===================================================================
--- src/com/google/inject/spi/CachedValue.java	Mon Apr 06 10:36:06 BST 2009
+++ src/com/google/inject/spi/CachedValue.java	Mon Apr 06 10:36:06 BST 2009
@@ -0,0 +1,33 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.inject.spi;
+
+/**
+ * An interface to expose a cached value in a provider such as for a Scope.
+ * A Scope may choose to implement this method so that it can expose the current value in the scope
+ *
+ * @version $Revision: 1.1 $
+ */
+public interface CachedValue<T> {
+  /**
+   * Returns the currently cached value in a scope if its available or supported or null if there is
+   * no cached value yet or caching is not supported.
+   */
+  T getCachedValue();
+}
Index: src/com/google/inject/InternalFactoryToProviderAdapter.java
===================================================================
--- src/com/google/inject/InternalFactoryToProviderAdapter.java	(revision 925)
+++ src/com/google/inject/InternalFactoryToProviderAdapter.java	Mon Apr 06 10:50:44 BST 2009
@@ -22,12 +22,13 @@
 import com.google.inject.internal.InternalFactory;
 import static com.google.inject.internal.Preconditions.checkNotNull;
 import com.google.inject.internal.SourceProvider;
+import com.google.inject.spi.CachedValue;
 import com.google.inject.spi.Dependency;
 
 /**
  * @author crazybob@google.com (Bob Lee)
 */
-class InternalFactoryToProviderAdapter<T> implements InternalFactory<T> {
+class InternalFactoryToProviderAdapter<T> implements InternalFactory<T>, CachedValue<T> {
 
   private final Initializable<Provider<? extends T>> initializable;
   private final Object source;
@@ -54,4 +55,19 @@
   @Override public String toString() {
     return initializable.toString();
   }
+
+  public T getCachedValue() {
+    try {
+      Provider<? extends T> provider = initializable.get(new Errors(this));
+      if (provider instanceof CachedValue) {
+        @SuppressWarnings("unchecked")
+        CachedValue<T> cachedValue = (CachedValue<T>) provider;
+        return cachedValue.getCachedValue();
-}
+      }
+    }
+    catch (ErrorsException e) {
+      // ignore
+    }
+    return null;
+  }
+}
Index: src/com/google/inject/InjectorImpl.java
===================================================================
--- src/com/google/inject/InjectorImpl.java	(revision 925)
+++ src/com/google/inject/InjectorImpl.java	Mon Apr 06 10:50:44 BST 2009
@@ -37,6 +37,8 @@
 import com.google.inject.internal.SourceProvider;
 import com.google.inject.internal.ToStringBuilder;
 import com.google.inject.spi.BindingTargetVisitor;
+import com.google.inject.spi.CachedValue;
+import com.google.inject.spi.CachingProvider;
 import com.google.inject.spi.ConvertedConstantBinding;
 import com.google.inject.spi.Dependency;
 import com.google.inject.spi.InjectionPoint;
@@ -748,7 +750,7 @@
     final InternalFactory<? extends T> factory = getInternalFactory(key, errors);
     final Dependency<T> dependency = Dependency.get(key);
 
-    return new Provider<T>() {
+    return new CachingProvider<T>() {
       public T get() {
         final Errors errors = new Errors(dependency);
         try {
@@ -772,6 +774,15 @@
       @Override public String toString() {
         return factory.toString();
       }
+
+      public T getCachedValue() {
+        if (factory instanceof CachedValue) {
+          @SuppressWarnings("unchecked")
+          CachedValue<T> cachedValue = (CachedValue<T>) factory;
+          return cachedValue.getCachedValue();
+        }
+        return null;
+      }
     };
   }
 
Index: src/com/google/inject/ConstructorBindingImpl.java
===================================================================
--- src/com/google/inject/ConstructorBindingImpl.java	(revision 925)
+++ src/com/google/inject/ConstructorBindingImpl.java	Mon Apr 06 10:36:06 BST 2009
@@ -25,6 +25,7 @@
 import com.google.inject.internal.Scoping;
 import com.google.inject.internal.ToStringBuilder;
 import com.google.inject.spi.BindingTargetVisitor;
+import com.google.inject.spi.CachedValue;
 import com.google.inject.spi.ConstructorBinding;
 import com.google.inject.spi.Dependency;
 import com.google.inject.spi.InjectableType;
@@ -87,7 +88,7 @@
         .toString();
   }
 
-  private static class Factory<T> implements InternalFactory<T> {
+  private static class Factory<T> implements InternalFactory<T>, CachedValue<T> {
     private ConstructorInjector<T> constructorInjector;
 
     @SuppressWarnings("unchecked")
@@ -99,5 +100,9 @@
       // client needs), but it should be OK in practice thanks to the wonders of erasure.
       return (T) constructorInjector.construct(errors, context, dependency.getKey().getRawType());
     }
+
+    public T getCachedValue() {
+      return constructorInjector.getCachedValue();
-  }
-}
+    }
+  }
+}
Index: src/com/google/inject/spi/InjectableType.java
===================================================================
--- src/com/google/inject/spi/InjectableType.java	(revision 925)
+++ src/com/google/inject/spi/InjectableType.java	Thu Apr 02 12:07:54 BST 2009
@@ -220,6 +220,23 @@
      */
     void register(InjectionListener<? super I> listener);
 
+    /**
+     * Registers a post injection listener for type {@code I}. Guice will notify the listener after
+     * injecting an instance of {@code I} and invoking all of the other injection listeners
+     * registered via the {@link #register(InjectionListener)}.
+     *
+     * This hook is intended for things like @PostConstruct from JSR 250 or
+     * for InitializingBean from Spring so that you can be notified when all the mutations on the
+     * injectee have completed.
+     *
+     * The order in which Guice will invoke these listeners is
+     * unspecified - other than they are all invoked after the listeners registered via the
+     * {@link #register(InjectionListener)} method.
+     *
+     * @param listener for post injections of instances of type {@code I}
+     */
+    void registerPostInjectListener(InjectionListener<? super I> listener);
+
     /*if[AOP]*/
     /**
      * Binds method interceptor[s] to methods matched in type {@code I} and its supertypes. A
Index: src/com/google/inject/EncounterImpl.java
===================================================================
--- src/com/google/inject/EncounterImpl.java	(revision 925)
+++ src/com/google/inject/EncounterImpl.java	Thu Apr 02 11:38:26 BST 2009
@@ -18,6 +18,7 @@
 
 import com.google.inject.internal.Errors;
 import com.google.inject.internal.ImmutableList;
+import com.google.inject.internal.Iterables;
 import com.google.inject.internal.Lists;
 import static com.google.inject.internal.Preconditions.checkState;
 import com.google.inject.matcher.Matcher;
@@ -37,6 +38,7 @@
   private final Errors errors;
   private final Lookups lookups;
   private List<InjectionListener<? super T>> injectionListeners; // lazy
+  private List<InjectionListener<? super T>> postInjectListeners; // lazy
   private List<MethodAspect> aspects; // lazy
   private boolean valid = true;
 
@@ -62,10 +64,20 @@
   }
 
   public ImmutableList<InjectionListener<? super T>> getInjectionListeners() {
-    return injectionListeners == null
+    if (injectionListeners != null) {
+      if (postInjectListeners == null) {
+        return ImmutableList.copyOf(injectionListeners);
+      }
+      else {
+        return ImmutableList.copyOf(Iterables.concat(injectionListeners, postInjectListeners));
+      }
+    }
+    else {
+      return postInjectListeners == null
-        ? ImmutableList.<InjectionListener<? super T>>of()
+          ? ImmutableList.<InjectionListener<? super T>>of()
-        : ImmutableList.copyOf(injectionListeners);
+          : ImmutableList.copyOf(postInjectListeners);
-  }
+    }
+  }
 
   @SuppressWarnings("unchecked") // an InjectionListener<? super T> is an InjectionListener<T>
   public void register(InjectionListener<? super T> injectionListener) {
@@ -78,6 +90,17 @@
     injectionListeners.add(injectionListener);
   }
 
+  @SuppressWarnings("unchecked") // an InjectionListener<? super T> is an InjectionListener<T>
+  public void registerPostInjectListener(InjectionListener<? super T> injectionListener) {
+    checkState(valid, "Encounters may not be used after hear() returns.");
+
+    if (postInjectListeners == null) {
+      postInjectListeners = Lists.newArrayList();
+    }
+
+    postInjectListeners.add(injectionListener);
+  }
+
   public void bindInterceptor(Matcher<? super Method> methodMatcher,
       MethodInterceptor... interceptors) {
     checkState(valid, "Encounters may not be used after hear() returns.");
Index: src/com/google/inject/ConstructorInjector.java
===================================================================
--- src/com/google/inject/ConstructorInjector.java	(revision 925)
+++ src/com/google/inject/ConstructorInjector.java	Mon Apr 06 10:42:33 BST 2009
@@ -23,6 +23,7 @@
 import com.google.inject.internal.InternalContext;
 import com.google.inject.spi.InjectableType;
 import com.google.inject.spi.InjectionListener;
+import com.google.inject.spi.CachedValue;
 import java.lang.reflect.InvocationTargetException;
 
 /**
@@ -31,7 +32,7 @@
  *
  * @author crazybob@google.com (Bob Lee)
  */
-class ConstructorInjector<T> {
+class ConstructorInjector<T> implements CachedValue<T> {
 
   private final ImmutableList<SingleParameterInjector<?>> parameterInjectors;
   private final ConstructionProxy<T> constructionProxy;
@@ -116,4 +117,9 @@
   public InjectableType<T> getInjectableType() {
     return injectableType;
   }
+
+  public T getCachedValue() {
+    // TODO
+    return null; //constructionProxy.getCachedValue();
-}
+  }
+}
Index: test/com/google/inject/InjectableTypeListenerTest.java
===================================================================
--- test/com/google/inject/InjectableTypeListenerTest.java	(revision 925)
+++ test/com/google/inject/InjectableTypeListenerTest.java	Thu Apr 02 12:10:10 BST 2009
@@ -509,4 +509,75 @@
       return "beep";
     }
   }
+
+  public void testPostInjectListenersAreProcessedInOrder() throws Exception {
+    final AtomicInteger counter = new AtomicInteger(0);
+    final List<Exception> failures = Lists.newArrayList();
+
+    Injector injector = Guice.createInjector(new AbstractModule() {
+      protected void configure() {
+
+        // this test is a little naughty as its also testing that the later you register a listener
+        // the later you will be invoked when the javadoc explicitly gives no ordering
+        // guarrentees - but I couldn't think of an easier way to test
+        // that the post inject listeners are definitely invoked after the other listeners
+
+        bindListener(any(), new InjectableType.Listener() {
+          public <I> void hear(InjectableType<I> injectableType, Encounter<I> encounter) {
+            encounter.registerPostInjectListener(new OrderedListener(counter, failures, 3));
-}
+          }
+        });
+
+        bindListener(any(), new InjectableType.Listener() {
+          public <I> void hear(InjectableType<I> injectableType, Encounter<I> encounter) {
+            encounter.register(new OrderedListener(counter, failures, 1));
+          }
+        });
+
+        bindListener(any(), new InjectableType.Listener() {
+          public <I> void hear(InjectableType<I> injectableType, Encounter<I> encounter) {
+            encounter.registerPostInjectListener(new OrderedListener(counter, failures, 4));
+          }
+        });
+
+        bindListener(any(), new InjectableType.Listener() {
+          public <I> void hear(InjectableType<I> injectableType, Encounter<I> encounter) {
+            encounter.register(new OrderedListener(counter, failures, 2));
+          }
+        });
+
+        bind(C.class);
+      }
+    });
+
+    injector.getInstance(C.class);
+
+    if (!failures.isEmpty()) {
+      throw failures.get(0);
+    }
+    assertEquals("Listener counter", 4, counter.get());
+  }
+
+  static class OrderedListener<I> implements InjectionListener<I> {
+    final List<Exception> failures;
+    final AtomicInteger counter;
+    final int expectedValue;
+
+    OrderedListener(AtomicInteger counter, List<Exception> failures, int expectedValue) {
+      this.counter = counter;
+      this.failures = failures;
+      this.expectedValue = expectedValue;
+    }
+
+    public void afterInjection(I injectee) {
+      int actualValue = counter.incrementAndGet();
+      try {
+        assertEquals("Listener invocation counter", expectedValue, actualValue);
+      }
+      catch (Exception e) {
+        failures.add(e);
+      }
+    }
+  }
+
+}
Index: test/com/google/inject/ScopesTest.java
===================================================================
--- test/com/google/inject/ScopesTest.java	(revision 925)
+++ test/com/google/inject/ScopesTest.java	Mon Apr 06 10:57:41 BST 2009
@@ -18,6 +18,7 @@
 
 import static com.google.inject.Asserts.assertContains;
 import com.google.inject.internal.Maps;
+import com.google.inject.spi.CachingProvider;
 import java.io.IOException;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -28,6 +29,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import junit.framework.TestCase;
 
 /**
@@ -137,6 +139,44 @@
     }
   }
 
+
+  public void testIterateThroughSingletonValues() {
+    Injector injector = Guice.createInjector(singletonsModule);
+
+    Binding<BoundAsSingleton> binding1 = injector.getBinding(BoundAsSingleton.class);
+    Provider<BoundAsSingleton> provider1 = binding1.getProvider();
+    provider1.get();
+
+    boolean foundBoundAsSingleton = false;
+    boolean foundEagerSingleton = false;
+
+
+    // now lets iterate through all the objects
+    Set<Map.Entry<Key<?>,Binding<?>>> entries = injector.getBindings().entrySet();
+    for (Map.Entry<Key<?>, Binding<?>> entry : entries) {
+      Key<?> key = entry.getKey();
+      Binding<?> binding = entry.getValue();
+      Provider<?> provider = binding.getProvider();
+      if (provider instanceof CachingProvider<?>) {
+        CachingProvider<?> cachingProvider = (CachingProvider<?>) provider;
+        Object value = cachingProvider.getCachedValue();
+        if (value != null) {
+          if (value instanceof BoundAsSingleton) {
+            foundBoundAsSingleton = true;
+          }
+          else if (value instanceof EagerSingleton) { 
+            foundEagerSingleton = true;
+          }
+          //System.out.println("Key: " + key + " value " + value);
+        }
+      }
+    }
+
+    assertTrue("Should have found bound singleton instance", foundBoundAsSingleton);
+    assertTrue("Should have found eager singleton instance", foundEagerSingleton);
+  }
+
+
   @Singleton
   interface A {}
   static class AImpl implements A {}
Index: src/com/google/inject/spi/CachingProvider.java
===================================================================
--- src/com/google/inject/spi/CachingProvider.java	Mon Apr 06 10:36:06 BST 2009
+++ src/com/google/inject/spi/CachingProvider.java	Mon Apr 06 10:36:06 BST 2009
@@ -0,0 +1,31 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.inject.spi;
+
+import com.google.inject.Provider;
+
+/**
+ * A Scope may choose to implement this method so that it can expose the current value in the scope.
+ * This interface combines the {@link Provider} and {@link CachedValue} together so that it is
+ * easier to create an inner class inside a Scope implementation.
+ *
+ * @version $Revision: 1.1 $
+ */
+public interface CachingProvider<T> extends Provider<T>, CachedValue<T> {
+}
Index: src/com/google/inject/Scopes.java
===================================================================
--- src/com/google/inject/Scopes.java	(revision 925)
+++ src/com/google/inject/Scopes.java	Mon Apr 06 10:28:02 BST 2009
@@ -19,6 +19,7 @@
 import com.google.inject.internal.Errors;
 import com.google.inject.internal.InternalFactory;
 import com.google.inject.internal.Scoping;
+import com.google.inject.spi.CachingProvider;
 import java.lang.annotation.Annotation;
 
 /**
@@ -35,7 +36,7 @@
    */
   public static final Scope SINGLETON = new Scope() {
     public <T> Provider<T> scope(Key<T> key, final Provider<T> creator) {
-      return new Provider<T>() {
+      return new CachingProvider<T>() {
 
         private volatile T instance;
 
@@ -58,6 +59,10 @@
           return instance;
         }
 
+        public T getCachedValue() {
+          return instance;
+        }
+
         public String toString() {
           return String.format("%s[%s]", creator, SINGLETON);
         }
Index: servlet/src/com/google/inject/servlet/ServletScopes.java
===================================================================
--- servlet/src/com/google/inject/servlet/ServletScopes.java	(revision 925)
+++ servlet/src/com/google/inject/servlet/ServletScopes.java	Mon Apr 06 10:28:02 BST 2009
@@ -22,6 +22,7 @@
 import com.google.inject.Scope;
 import com.google.inject.Scopes;
 import com.google.inject.Singleton;
+import com.google.inject.spi.CachingProvider;
 import com.google.inject.spi.DefaultBindingScopingVisitor;
 import java.lang.annotation.Annotation;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -43,7 +44,7 @@
   public static final Scope REQUEST = new Scope() {
     public <T> Provider<T> scope(Key<T> key, final Provider<T> creator) {
       final String name = key.toString();
-      return new Provider<T>() {
+      return new CachingProvider<T>() {
         public T get() {
           HttpServletRequest request = GuiceFilter.getRequest();
           synchronized (request) {
@@ -60,6 +61,15 @@
         public String toString() {
           return String.format("%s[%s]", creator, REQUEST);
         }
+
+        public T getCachedValue() {
+          HttpServletRequest request = GuiceFilter.getRequest();
+          synchronized (request) {
+            @SuppressWarnings("unchecked")
+            T t = (T) request.getAttribute(name);
+            return t;
+          }
+        }
       };
     }
 
@@ -74,7 +84,7 @@
   public static final Scope SESSION = new Scope() {
     public <T> Provider<T> scope(Key<T> key, final Provider<T> creator) {
       final String name = key.toString();
-      return new Provider<T>() {
+      return new CachingProvider<T>() {
         public T get() {
           HttpSession session = GuiceFilter.getRequest().getSession();
           synchronized (session) {
@@ -87,9 +97,19 @@
             return t;
           }
         }
+
         public String toString() {
           return String.format("%s[%s]", creator, SESSION);
         }
+
+        public T getCachedValue() {
+          HttpSession session = GuiceFilter.getRequest().getSession();
+          synchronized (session) {
+            @SuppressWarnings("unchecked")
+            T t = (T) session.getAttribute(name);
+            return t;
+          }
+        }
       };
     }