Migrated attachment for Guice issue 778, comment 1

BindingFactory.txt

Index: test/com/google/inject/commands/CommandRecorderTest.java
===================================================================
--- test/com/google/inject/commands/CommandRecorderTest.java	(revision 486)
+++ test/com/google/inject/commands/CommandRecorderTest.java	(working copy)
@@ -760,6 +760,10 @@
     public Void visitGetProvider(GetProviderCommand command) {
       throw new AssertionFailedError();
     }
+
+    public Void visitAddBindingFactory(AddBindingFactoryCommand command) {
+      throw new AssertionFailedError();
+    }
   }
 
   @Retention(RUNTIME)
Index: src/com/google/inject/matcher/Matchers.java
===================================================================
--- src/com/google/inject/matcher/Matchers.java	(revision 491)
+++ src/com/google/inject/matcher/Matchers.java	(working copy)
@@ -17,12 +17,15 @@
 package com.google.inject.matcher;
 
 import com.google.inject.internal.Objects;
+import com.google.inject.spi.Dependency;
 
 import java.io.Serializable;
 import java.lang.annotation.Annotation;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Member;
 import java.lang.reflect.Method;
 
 /**
@@ -340,4 +343,111 @@
       return "returns(" + returnType + ")";
     }
   }
+
+  /**
+   * Helper class to allow matching of annotations decoupled from their element
+   */
+  private static final class AnnotationBucket implements AnnotatedElement {
+    private final Annotation[] annotations;
+    public AnnotationBucket(Annotation... annotations) {
+      this.annotations = annotations;
+    }
+    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
+      for (Annotation a : annotations) {
+        if (annotationClass.isInstance(a)) {
+          return annotationClass.cast(a);
+        }
+      }
+      return null;
+    }
+    public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {
+      return getAnnotation(annotationClass) != null;
+    }
+    public Annotation[] getAnnotations() {
+      return annotations;
+    }
+    public Annotation[] getDeclaredAnnotations() {
+      return annotations;
+    }
+  }
+
+  /**
+   * Returns a matcher which matches dependencies with matching key annotations.
+   */
+  public static Matcher<Dependency<?>> key(
+      Matcher<AnnotatedElement> keyAnnotation) {
+    return new DependencyKey(keyAnnotation);
+  }
+
+  private static final class DependencyKey extends
+      AbstractMatcher<Dependency<?>> implements Serializable {
+    private final Matcher<AnnotatedElement> keyAnnotation;
+
+    public DependencyKey(Matcher<AnnotatedElement> keyAnnotation) {
+      this.keyAnnotation = Objects.nonNull(keyAnnotation, "key annotation matcher");
+    }
+
+    public boolean matches(Dependency<?> d) {
+      return keyAnnotation.matches(new AnnotationBucket(d.getKey().getAnnotation()));
+    }
+
+    @Override public boolean equals(Object other) {
+      return other instanceof DependencyKey
+          && ((DependencyKey) other).keyAnnotation.equals(keyAnnotation);
+    }
+
+    @Override public int hashCode() {
+      return 37 * keyAnnotation.hashCode();
+    }
+
+    @Override public String toString() {
+      return "key(" + keyAnnotation + ")";
+    }
+  }
+
+  /**
+   * Returns a matcher which matches dependencies with matching member annotations.
+   */
+  public static Matcher<Dependency<?>> member(
+      Matcher<AnnotatedElement> memberAnnotation) {
+    return new DependencyMember(memberAnnotation);
+  }
+
+  private static final class DependencyMember extends
+      AbstractMatcher<Dependency<?>> implements Serializable {
+    private final Matcher<AnnotatedElement> memberAnnotation;
+
+    public DependencyMember(Matcher<AnnotatedElement> memberAnnotation) {
+      this.memberAnnotation = Objects.nonNull(memberAnnotation, "member annotation matcher");
+    }
+
+    public boolean matches(Dependency<?> d) {
+      Member m = d.getMember();
+      int i = d.getParameterIndex();
+      Annotation[] as = new Annotation[0];
+
+      if (i < 0) {
+        as = ((AnnotatedElement)m).getAnnotations();
+      } else if (m instanceof Constructor) {
+        as = ((Constructor<?>)m).getParameterAnnotations()[i];
+      } else if (m instanceof Method) {
+        as = ((Method)m).getParameterAnnotations()[i];
+      }
+
+      return memberAnnotation.matches(new AnnotationBucket(as));
+    }
+
+    @Override public boolean equals(Object other) {
+      return other instanceof DependencyMember
+          && ((DependencyMember) other).memberAnnotation.equals(memberAnnotation);
+    }
+
+    @Override public int hashCode() {
+      return 37 * memberAnnotation.hashCode();
+    }
+
+    @Override public String toString() {
+      return "member(" + memberAnnotation + ")";
+    }
+  }
 }
\ No newline at end of file
Index: src/com/google/inject/Binder.java
===================================================================
--- src/com/google/inject/Binder.java	(revision 486)
+++ src/com/google/inject/Binder.java	(working copy)
@@ -20,6 +20,7 @@
 import com.google.inject.binder.AnnotatedConstantBindingBuilder;
 import com.google.inject.binder.LinkedBindingBuilder;
 import com.google.inject.matcher.Matcher;
+import com.google.inject.spi.Dependency;
 import com.google.inject.spi.Message;
 import com.google.inject.spi.TypeConverter;
 import java.lang.annotation.Annotation;
@@ -284,4 +285,15 @@
    */
   void convertToTypes(Matcher<? super TypeLiteral<?>> typeMatcher,
       TypeConverter converter);
+
+  /**
+   * Adds a binding factory to provide missing dependencies matched by a matcher.
+   *
+   * @param dependencyMatcher matches missing dependencies the binding factory
+   *     should attempt to satisfy. For example: {@code any()}.
+   * @param bindingFactory factory that can produce bindings on request
+   */
+  <T> void addBindingFactory(
+      Matcher<? super Dependency<? extends T>> dependencyMatcher,
+          BindingFactory<T> bindingFactory);
 }
Index: src/com/google/inject/internal/ResolvingCallable.java
===================================================================
--- src/com/google/inject/internal/ResolvingCallable.java	(revision 486)
+++ src/com/google/inject/internal/ResolvingCallable.java	(working copy)
@@ -29,9 +29,22 @@
  */
 public abstract class ResolvingCallable<T> implements Callable<T> {
   public abstract T call() throws ResolveFailedException;
+  public boolean retry() {return false;}
 
   public T runWithDefaultSource(Object source) throws ResolveFailedException {
     try {
+      return run(source);
+    } catch (ResolveFailedException e) {
+      if (retry()) {
+        return run(source);
+      } else {
+        throw e;
+      }
+    }
+  }
+
+  private T run(Object source) throws ResolveFailedException {
+    try {
       return SourceProviders.withDefaultChecked(source, this);
     } catch (ResolveFailedException e) {
       throw e;
Index: src/com/google/inject/InjectorImpl.java
===================================================================
--- src/com/google/inject/InjectorImpl.java	(revision 486)
+++ src/com/google/inject/InjectorImpl.java	(working copy)
@@ -78,6 +78,8 @@
   final ErrorHandler errorHandler;
   Reflection reflection;
 
+  MissingDependencyHandler missingDependencyHandler;
+
   InjectorImpl(Injector parentInjector, ErrorHandler errorHandler) {
     this.parentInjector = parentInjector;
     this.errorHandler = errorHandler;
@@ -155,6 +157,10 @@
     SourceProviders.withDefault(defaultSource, runnable);
   }
 
+  void setMissingDependencyHandler(MissingDependencyHandler dependencyHandler) {
+    this.missingDependencyHandler = dependencyHandler;
+  }
+
   /**
    * Returns the binding for {@code key}, or {@code null} if that binding
    * cannot be resolved.
@@ -854,14 +860,20 @@
 
       final Key<?> key = Keys.get(
           field.getGenericType(), field, field.getAnnotations(), errorHandler);
+
+      this.injectionPoint = InjectionPoint.newInstance(field,
+          Nullability.forAnnotations(field.getAnnotations()), key, injector);
+
+      final MissingDependencyHandler handler = missingDependencyHandler;
+
       factory = new ResolvingCallable<InternalFactory<?>>() {
           public InternalFactory<?> call() throws ResolveFailedException {
             return injector.getInternalFactory(key);
           }
+          public boolean retry() {
+            return null == handler ? false : handler.handle(injectionPoint);
+          }
         }.runWithDefaultSource(StackTraceElements.forMember(field));
-
-      this.injectionPoint = InjectionPoint.newInstance(field,
-          Nullability.forAnnotations(field.getAnnotations()), key, injector);
     }
 
     public Collection<Dependency<?>> getDependencies() {
@@ -916,15 +928,22 @@
   <T> SingleParameterInjector<T> createParameterInjector(
       final Parameter<T> parameter, Member member)
       throws ResolveFailedException {
+
+    final InjectionPoint<T> injectionPoint = InjectionPoint.newInstance(
+        member, parameter.getIndex(), parameter.getNullability(), parameter.getKey(), this);
+
+    final MissingDependencyHandler handler = missingDependencyHandler;
+
     InternalFactory<? extends T> factory
         = new ResolvingCallable<InternalFactory<? extends T>>() {
           public InternalFactory<? extends T> call() throws ResolveFailedException {
             return getInternalFactory(parameter.getKey());
           }
+          public boolean retry() {
+            return null == handler ? false : handler.handle(injectionPoint);
+          }
     }.runWithDefaultSource(StackTraceElements.forMember(member));
 
-    InjectionPoint<T> injectionPoint = InjectionPoint.newInstance(
-        member, parameter.getIndex(), parameter.getNullability(), parameter.getKey(), this);
     return new SingleParameterInjector<T>(injectionPoint, factory);
   }
 
Index: src/com/google/inject/commands/CommandRecorder.java
===================================================================
--- src/com/google/inject/commands/CommandRecorder.java	(revision 486)
+++ src/com/google/inject/commands/CommandRecorder.java	(working copy)
@@ -22,6 +22,8 @@
 import com.google.inject.matcher.Matcher;
 import com.google.inject.spi.SourceProviders;
 import static com.google.inject.spi.SourceProviders.defaultSource;
+import com.google.inject.internal.ErrorHandler;
+import com.google.inject.spi.Dependency;
 import com.google.inject.spi.TypeConverter;
 import org.aopalliance.intercept.MethodInterceptor;
 
@@ -115,10 +117,19 @@
       commands.add(new AddThrowableErrorCommand(defaultSource(), t));
     }
 
+    private final class BindingErrorHandler implements ErrorHandler {
+      public void handle(Object source, String message) {
+        commands.add(new AddMessageErrorCommand(source, message, new Object[0]));
+      }
+      public void handle(Object source, String message, Object... arguments) {
+        commands.add(new AddMessageErrorCommand(source, message, arguments));
+      }
+    }
+
     public <T> BindCommand<T>.BindingBuilder bind(Key<T> key) {
       BindCommand<T> bindCommand = new BindCommand<T>(defaultSource(), key);
       commands.add(bindCommand);
-      return bindCommand.bindingBuilder(RecordingBinder.this);
+      return bindCommand.bindingBuilder(new BindingErrorHandler());
     }
 
     public <T> AnnotatedBindingBuilder<T> bind(TypeLiteral<T> typeLiteral) {
@@ -132,7 +143,7 @@
     public AnnotatedConstantBindingBuilder bindConstant() {
       BindConstantCommand bindConstantCommand = new BindConstantCommand(defaultSource());
       commands.add(bindConstantCommand);
-      return bindConstantCommand.bindingBuilder(RecordingBinder.this);
+      return bindConstantCommand.bindingBuilder(new BindingErrorHandler());
     }
 
     public <T> Provider<T> getProvider(final Key<T> key) {
@@ -157,6 +168,13 @@
       commands.add(new ConvertToTypesCommand(defaultSource(), typeMatcher, converter));
     }
 
+    public <T> void addBindingFactory(
+        Matcher<? super Dependency<? extends T>> dependencyMatcher,
+            BindingFactory<T> bindingFactory) {
+      commands.add(new AddBindingFactoryCommand<T>(
+          defaultSource(), dependencyMatcher, bindingFactory));
+    }
+
     @Override public String toString() {
       return "Binder";
     }
Index: src/com/google/inject/commands/AddBindingFactoryCommand.java
===================================================================
--- src/com/google/inject/commands/AddBindingFactoryCommand.java	(revision 0)
+++ src/com/google/inject/commands/AddBindingFactoryCommand.java	(revision 0)
@@ -0,0 +1,58 @@
+/**
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed 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.commands;
+
+import com.google.inject.BindingFactory;
+import static com.google.inject.internal.Objects.nonNull;
+import com.google.inject.matcher.Matcher;
+import com.google.inject.spi.Dependency;
+
+/**
+ * Immutable snapshot of a request to add a binding factory.
+ *
+ * @author stuart.mcculloch@jayway.net (Stuart McCulloch)
+ */
+public final class AddBindingFactoryCommand<T> implements Command {
+  private final Object source;
+  private final Matcher<? super Dependency<? extends T>> dependencyMatcher;
+  private final BindingFactory<T> bindingFactory;
+
+  AddBindingFactoryCommand(
+      Object source,
+      Matcher<? super Dependency<? extends T>> dependencyMatcher,
+      BindingFactory<T> bindingFactory) {
+    this.source = nonNull(source, "source");
+    this.dependencyMatcher = nonNull(dependencyMatcher, "dependencyMatcher");
+    this.bindingFactory = nonNull(bindingFactory, "bindingFactory");
+  }
+
+  public Object getSource() {
+    return source;
+  }
+
+  public Matcher<? super Dependency<? extends T>> getDependencyMatcher() {
+    return dependencyMatcher;
+  }
+
+  public BindingFactory<T> getBindingFactory() {
+    return bindingFactory;
+  }
+
+  public <V> V acceptVisitor(Visitor<V> visitor) {
+    return visitor.visitAddBindingFactory(this);
+  }
+}

Property changes on: src/com/google/inject/commands/AddBindingFactoryCommand.java
___________________________________________________________________
Name: svn:eol-style
   + native

Index: src/com/google/inject/commands/BindCommand.java
===================================================================
--- src/com/google/inject/commands/BindCommand.java	(revision 486)
+++ src/com/google/inject/commands/BindCommand.java	(working copy)
@@ -22,8 +22,11 @@
 import com.google.inject.binder.LinkedBindingBuilder;
 import com.google.inject.binder.ScopedBindingBuilder;
 import com.google.inject.internal.ErrorMessages;
+import com.google.inject.internal.ErrorHandler;
 import static com.google.inject.internal.Objects.nonNull;
+import com.google.inject.spi.Dependency;
 import com.google.inject.spi.SourceProviders;
+import static com.google.inject.spi.SourceProviders.defaultSource;
 
 import java.lang.annotation.Annotation;
 
@@ -123,18 +126,18 @@
     }
   }
 
-  BindingBuilder bindingBuilder(Binder binder) {
-    return new BindingBuilder(binder);
+  BindingBuilder bindingBuilder(ErrorHandler errorHandler) {
+    return new BindingBuilder(errorHandler);
   }
 
   /**
    * Package-private write access to the internal state of this command.
    */
   class BindingBuilder implements AnnotatedBindingBuilder<T> {
-    private final Binder binder;
+    private final ErrorHandler errorHandler;
 
-    BindingBuilder(Binder binder) {
-      this.binder = binder;
+    BindingBuilder(ErrorHandler errorHandler) {
+      this.errorHandler = errorHandler;
     }
 
     public LinkedBindingBuilder<T> annotatedWith(
@@ -316,25 +319,25 @@
 
     private void checkNotTargetted() {
       if (bindTarget != EMPTY_BIND_TARGET) {
-        binder.addError(IMPLEMENTATION_ALREADY_SET);
+        errorHandler.handle(source, IMPLEMENTATION_ALREADY_SET);
       }
     }
 
     private void checkNotAnnotated() {
       if (BindCommand.this.key.getAnnotationType() != null) {
-        binder.addError(ANNOTATION_ALREADY_SPECIFIED);
+         errorHandler.handle(source, ANNOTATION_ALREADY_SPECIFIED);
       }
     }
 
     private void checkNotScoped() {
       // Scoping isn't allowed when we have only one instance.
       if (bindTarget.get() != null) {
-        binder.addError(SINGLE_INSTANCE_AND_SCOPE);
+        errorHandler.handle(source, SINGLE_INSTANCE_AND_SCOPE);
         return;
       }
 
       if (bindScoping != EMPTY_SCOPING) {
-        binder.addError(SCOPE_ALREADY_SET);
+        errorHandler.handle(source, SCOPE_ALREADY_SET);
       }
     }
 
@@ -345,4 +348,22 @@
       return type + key.getTypeLiteral() + ">";
     }
   }
+
+  /**
+   * Attempt to add a missing binding to the injector by using a binding factory
+   */
+  public static <B, T extends B> BindCommand<T> lateBinding(ErrorHandler errorHandler,
+      Dependency<T> dependency, BindingFactory<B> bindingFactory) {
+
+    BindCommand<T> bindCommand = new BindCommand<T>(
+        defaultSource(), dependency.getKey());
+
+    LinkedBindingBuilder<T> lbb = bindCommand.bindingBuilder(errorHandler);
+
+    if (bindingFactory.bind(dependency, lbb)) {
+      return bindCommand;
+    } else {
+      return null;
+    }
+  }
 }
Index: src/com/google/inject/commands/Command.java
===================================================================
--- src/com/google/inject/commands/Command.java	(revision 486)
+++ src/com/google/inject/commands/Command.java	(working copy)
@@ -38,5 +38,6 @@
     V visitConvertToTypes(ConvertToTypesCommand command);
     <T> V visitBind(BindCommand<T> command);
     <T> V visitGetProvider(GetProviderCommand<T> command);
+    <T> V visitAddBindingFactory(AddBindingFactoryCommand<T> command);
   }
 }
Index: src/com/google/inject/commands/CommandReplayer.java
===================================================================
--- src/com/google/inject/commands/CommandReplayer.java	(revision 486)
+++ src/com/google/inject/commands/CommandReplayer.java	(working copy)
@@ -100,6 +100,11 @@
         replayGetProvider(binder, command);
         return null;
       }
+
+      public <T> Void visitAddBindingFactory(AddBindingFactoryCommand<T> command) {
+        replayAddBindingFactory(binder, command);
+        return null;
+      }
     };
 
     for (Command command : commands) {
@@ -199,4 +204,12 @@
       }
     });
   }
+
+  public <T> void replayAddBindingFactory(final Binder binder, final AddBindingFactoryCommand<T> command) {
+    SourceProviders.withDefault(command.getSource(), new Runnable() {
+      public void run() {
+        binder.addBindingFactory(command.getDependencyMatcher(), command.getBindingFactory());
+      }
+    });
+  }
 }
Index: src/com/google/inject/commands/BindConstantCommand.java
===================================================================
--- src/com/google/inject/commands/BindConstantCommand.java	(revision 486)
+++ src/com/google/inject/commands/BindConstantCommand.java	(working copy)
@@ -16,13 +16,13 @@
 
 package com.google.inject.commands;
 
-import com.google.inject.Binder;
 import com.google.inject.Key;
 import com.google.inject.Provider;
 import com.google.inject.binder.AnnotatedConstantBindingBuilder;
 import com.google.inject.binder.ConstantBindingBuilder;
 import com.google.inject.binder.LinkedBindingBuilder;
 import com.google.inject.binder.ScopedBindingBuilder;
+import com.google.inject.internal.ErrorHandler;
 import com.google.inject.internal.Objects;
 import static com.google.inject.internal.Objects.nonNull;
 import com.google.inject.spi.SourceProviders;
@@ -102,8 +102,8 @@
     abstract <T> Key<T> getKey();
   }
 
-  BindingBuilder bindingBuilder(Binder binder) {
-    return new BindingBuilder(binder);
+  BindingBuilder bindingBuilder(ErrorHandler errorHandler) {
+    return new BindingBuilder(errorHandler);
   }
 
   /**
@@ -111,10 +111,10 @@
    */
   class BindingBuilder
       implements AnnotatedConstantBindingBuilder, ConstantBindingBuilder {
-    private final Binder binder;
+    private final ErrorHandler errorHandler;
 
-    BindingBuilder(Binder binder) {
-      this.binder = binder;
+    BindingBuilder(ErrorHandler errorHandler) {
+      this.errorHandler = errorHandler;
     }
 
     public ConstantBindingBuilder annotatedWith(final Class<? extends Annotation> annotationType) {
@@ -349,13 +349,13 @@
 
     private void assertNoBindingAnnotation() {
       if (bindingAnnotation != null) {
-        binder.addError(ANNOTATION_ALREADY_SPECIFIED);
+        errorHandler.handle(source, ANNOTATION_ALREADY_SPECIFIED);
       }
     }
 
     private void assertNoTarget() {
       if (target != null) {
-        binder.addError(CONSTANT_VALUE_ALREADY_SET);
+        errorHandler.handle(source, CONSTANT_VALUE_ALREADY_SET);
       }
     }
 
Index: src/com/google/inject/BindCommandProcessor.java
===================================================================
--- src/com/google/inject/BindCommandProcessor.java	(revision 486)
+++ src/com/google/inject/BindCommandProcessor.java	(working copy)
@@ -299,6 +299,7 @@
           original.getSource());
     } else {
       bindings.put(key, binding);
+      injector.index(binding);
     }
   }
 
Index: src/com/google/inject/InjectorBuilder.java
===================================================================
--- src/com/google/inject/InjectorBuilder.java	(revision 486)
+++ src/com/google/inject/InjectorBuilder.java	(working copy)
@@ -17,11 +17,14 @@
 package com.google.inject;
 
 import static com.google.inject.Scopes.SINGLETON;
+
+import com.google.inject.commands.BindCommand;
 import com.google.inject.commands.Command;
 import com.google.inject.commands.CommandRecorder;
 import com.google.inject.commands.FutureInjector;
 import com.google.inject.internal.Objects;
 import com.google.inject.internal.Stopwatch;
+import com.google.inject.spi.Dependency;
 import com.google.inject.spi.SourceProviders;
 
 import java.lang.reflect.Member;
@@ -98,6 +101,7 @@
     validate();
 
     errorHandler.switchToRuntime();
+    injector.setMissingDependencyHandler(null);
 
     // If we're in the tool stage, stop here. Don't eagerly inject or load
     // anything.
@@ -141,13 +145,19 @@
     bindCommandProcesor = new BindCommandProcessor(
         injector, injector.scopes, stage, injector.explicitBindings,
         injector.outstandingInjections);
+
+    AddBindingFactoryCommandProcessor addBindingFactoryCommandProcessor
+        = new AddBindingFactoryCommandProcessor(errorHandler);
+    addBindingFactoryCommandProcessor.processCommands(commands);
+    stopwatch.resetAndLog("Binding factory creation");
+
+    injector.setMissingDependencyHandler(new AddLateBindingHandler(
+        addBindingFactoryCommandProcessor.getBindingFactories()));
+
     bindCommandProcesor.processCommands(commands);
     bindCommandProcesor.createUntargettedBindings();
     stopwatch.resetAndLog("Binding creation");
 
-    injector.index();
-    stopwatch.resetAndLog("Binding indexing");
-
     requestStaticInjectionCommandProcessor
         = new RequestStaticInjectionCommandProcessor(errorHandler);
     requestStaticInjectionCommandProcessor
@@ -261,4 +271,25 @@
     }
   }
 
+  private final class AddLateBindingHandler implements MissingDependencyHandler {
+    final List<BindingFactory<?>> bindingFactories;
+
+    public AddLateBindingHandler(List<BindingFactory<?>> bindingFactories) {
+      this.bindingFactories = bindingFactories;
+    }
+
+    @SuppressWarnings("unchecked")
+    public boolean handle(Dependency dependency) {
+
+      // search in order of registration...
+      for (BindingFactory bindingFactory : bindingFactories) {
+        BindCommand command = BindCommand.lateBinding(errorHandler, dependency, bindingFactory);
+        if (command != null) {
+          bindCommandProcesor.visitBind(command);
+          return true;
+        }
+      }
+      return false;
+    }
+  }
 }
Index: src/com/google/inject/BindingFactory.java
===================================================================
--- src/com/google/inject/BindingFactory.java	(revision 0)
+++ src/com/google/inject/BindingFactory.java	(revision 0)
@@ -0,0 +1,41 @@
+/**
+ * Copyright (C) 2007 Google Inc.
+ *
+ * Licensed 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;
+
+import com.google.inject.binder.LinkedBindingBuilder;
+import com.google.inject.spi.Dependency;
+
+/**
+ * A factory capable of supplying bindings on request during construction of
+ * the {@code Injector}. Binding factories can be used to integrate service
+ * registries with Guice.
+ *
+ * @author stuart.mcculloch@jayway.net (Stuart McCulloch)
+ */
+public interface BindingFactory<B> {
+
+  /**
+   * Supplies bindings for missing dependencies that extend {@code B}
+   * 
+   * @param <T> a type of dependency this factory can supply
+   * @param dependency the missing dependency that needs a binding
+   * @param linkedBindingBuilder a partially constructed binding
+   * @return true if this factory could supply a binding
+   */
+  <T extends B> boolean bind(Dependency<T> dependency,
+      LinkedBindingBuilder<T> linkedBindingBuilder);
+}

Property changes on: src/com/google/inject/BindingFactory.java
___________________________________________________________________
Name: svn:eol-style
   + native

Index: src/com/google/inject/MissingDependencyHandler.java
===================================================================
--- src/com/google/inject/MissingDependencyHandler.java	(revision 0)
+++ src/com/google/inject/MissingDependencyHandler.java	(revision 0)
@@ -0,0 +1,32 @@
+/**
+ * Copyright (C) 2007 Google Inc.
+ *
+ * Licensed 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;
+
+import com.google.inject.spi.Dependency;
+
+/**
+ * Handles missing dependencies in the Injector.
+ *
+ * @author stuart.mcculloch@jayway.net (Stuart McCulloch)
+ */
+interface MissingDependencyHandler {
+
+  /**
+   * Handles a missing dependency.
+   */
+  boolean handle(Dependency<?> dependency);
+}

Property changes on: src/com/google/inject/MissingDependencyHandler.java
___________________________________________________________________
Name: svn:eol-style
   + native

Index: src/com/google/inject/AbstractModule.java
===================================================================
--- src/com/google/inject/AbstractModule.java	(revision 486)
+++ src/com/google/inject/AbstractModule.java	(working copy)
@@ -21,6 +21,7 @@
 import com.google.inject.binder.LinkedBindingBuilder;
 import com.google.inject.internal.Objects;
 import com.google.inject.matcher.Matcher;
+import com.google.inject.spi.Dependency;
 import com.google.inject.spi.SourceProviders;
 import com.google.inject.spi.TypeConverter;
 import java.lang.annotation.Annotation;
@@ -186,4 +187,13 @@
   protected Stage currentStage() {
     return binder.currentStage();
   }
+
+  /**
+   * @see Binder#addBindingFactory
+   */
+  protected <T> void addBindingFactory(
+      Matcher<? super Dependency<? extends T>> dependencyMatcher,
+          BindingFactory<T> bindingFactory) {
+    binder.addBindingFactory(dependencyMatcher, bindingFactory);
+  }
 }
Index: src/com/google/inject/AddBindingFactoryCommandProcessor.java
===================================================================
--- src/com/google/inject/AddBindingFactoryCommandProcessor.java	(revision 0)
+++ src/com/google/inject/AddBindingFactoryCommandProcessor.java	(revision 0)
@@ -0,0 +1,63 @@
+/**
+ * Copyright (C) 2008 Google Inc.
+ *
+ * Licensed 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;
+
+import com.google.inject.binder.LinkedBindingBuilder;
+import com.google.inject.commands.AddBindingFactoryCommand;
+import com.google.inject.internal.ErrorHandler;
+import com.google.inject.matcher.Matcher;
+import com.google.inject.spi.Dependency;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Handles {@link Binder#addBindingFactory} commands.
+ *
+ * @author stuart.mcculloch@jayway.net (Stuart McCulloch)
+ */
+final class AddBindingFactoryCommandProcessor extends CommandProcessor {
+
+  private final List<BindingFactory<?>> bindingFactories =
+      new ArrayList<BindingFactory<?>>();
+
+  public AddBindingFactoryCommandProcessor(ErrorHandler errorHandler) {
+    super(errorHandler);
+  }
+
+  @Override public <B> Boolean visitAddBindingFactory(
+      AddBindingFactoryCommand<B> command) {
+
+    final Matcher<? super Dependency<? extends B>> dependencyMatcher = command.getDependencyMatcher();
+    final BindingFactory<B> bindingFactory = command.getBindingFactory();
+
+    bindingFactories.add(new BindingFactory<B>() {
+      public <T extends B> boolean bind(Dependency<T> dependency, LinkedBindingBuilder<T> lbb) {
+        if (dependencyMatcher.matches(dependency)) {
+          return bindingFactory.bind(dependency, lbb);
+        }
+        return false;
+      }
+    });
+
+    return true;
+  }
+
+  List<BindingFactory<?>> getBindingFactories() {
+    return Collections.unmodifiableList(bindingFactories);
+  }
+}

Property changes on: src/com/google/inject/AddBindingFactoryCommandProcessor.java
___________________________________________________________________
Name: svn:eol-style
   + native

Index: src/com/google/inject/CommandProcessor.java
===================================================================
--- src/com/google/inject/CommandProcessor.java	(revision 486)
+++ src/com/google/inject/CommandProcessor.java	(working copy)
@@ -91,4 +91,8 @@
   public <T> Boolean visitGetProvider(GetProviderCommand<T> command) {
     return false;
   }
+
+  public <T> Boolean visitAddBindingFactory(AddBindingFactoryCommand<T> command) {
+    return false;
+  }
 }
Index: src/com/google/inject/commands/DefaultCommandVisitor.java
===================================================================
--- src/com/google/inject/commands/DefaultCommandVisitor.java  (revision 486)
+++ src/com/google/inject/commands/DefaultCommandVisitor.java  (working copy)
@@ -70,4 +70,8 @@
       RequestStaticInjectionCommand command) {
     return visitCommand(command);
   }
+
+  public <T> V visitAddBindingFactory(AddBindingFactoryCommand<T> command) {
+    return visitCommand(command);
+  }
 }