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/**
* Copyright (C) 2006 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.internal;
import com.google.common.collect.ImmutableSet;
import com.google.inject.internal.ProvisionListenerStackCallback.ProvisionCallback;
import com.google.inject.spi.InjectionPoint;
import java.lang.reflect.InvocationTargetException;
import java.util.Set;
/**
* Creates instances using an injectable constructor. After construction, all injectable fields and
* methods are injected.
*
* @author crazybob@google.com (Bob Lee)
*/
final class ConstructorInjector<T> {
private final ImmutableSet<InjectionPoint> injectableMembers;
private final SingleParameterInjector<?>[] parameterInjectors;
private final ConstructionProxy<T> constructionProxy;
private final MembersInjectorImpl<T> membersInjector;
ConstructorInjector(Set<InjectionPoint> injectableMembers,
ConstructionProxy<T> constructionProxy,
SingleParameterInjector<?>[] parameterInjectors,
MembersInjectorImpl<T> membersInjector) {
this.injectableMembers = ImmutableSet.copyOf(injectableMembers);
this.constructionProxy = constructionProxy;
this.parameterInjectors = parameterInjectors;
this.membersInjector = membersInjector;
}
public ImmutableSet<InjectionPoint> getInjectableMembers() {
return injectableMembers;
}
ConstructionProxy<T> getConstructionProxy() {
return constructionProxy;
}
/**
* Construct an instance. Returns {@code Object} instead of {@code T} because
* it may return a proxy.
*/
Object construct(final Errors errors, final InternalContext context,
Class<?> expectedType,
ProvisionListenerStackCallback<T> provisionCallback)
throws ErrorsException {
final ConstructionContext<T> constructionContext = context.getConstructionContext(this);
// We have a circular reference between constructors. Return a proxy.
if (constructionContext.isConstructing()) {
// TODO (crazybob): if we can't proxy this object, can we proxy the other object?
return constructionContext.createProxy(
errors, context.getInjectorOptions(), expectedType);
}
// If we're re-entering this factory while injecting fields or methods,
// return the same instance. This prevents infinite loops.
T t = constructionContext.getCurrentReference();
if (t != null) {
return t;
}
constructionContext.startConstruction();
try {
// Optimization: Don't go through the callback stack if we have no listeners.
if (!provisionCallback.hasListeners()) {
return provision(errors, context, constructionContext);
} else {
return provisionCallback.provision(errors, context, new ProvisionCallback<T>() {
public T call() throws ErrorsException {
return provision(errors, context, constructionContext);
}
});
}
} finally {
constructionContext.finishConstruction();
}
}
/** Provisions a new T. */
private T provision(Errors errors, InternalContext context,
ConstructionContext<T> constructionContext) throws ErrorsException {
try {
T t;
try {
Object[] parameters = SingleParameterInjector.getAll(errors, context, parameterInjectors);
t = constructionProxy.newInstance(parameters);
constructionContext.setProxyDelegates(t);
} finally {
constructionContext.finishConstruction();
}
// Store reference. If an injector re-enters this factory, they'll get the same reference.
constructionContext.setCurrentReference(t);
membersInjector.injectMembers(t, errors, context, false);
membersInjector.notifyListeners(t, errors);
return t;
} catch (InvocationTargetException userException) {
Throwable cause = userException.getCause() != null
? userException.getCause()
: userException;
throw errors.withSource(constructionProxy.getInjectionPoint())
.errorInjectingConstructor(cause).toException();
} finally {
constructionContext.removeCurrentReference();
}
}
}
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