com.google.inject.internal.ProviderMethod Maven / Gradle / Ivy
/**
* 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.internal;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableSet;
import com.google.inject.Binder;
import com.google.inject.Exposed;
import com.google.inject.Key;
import com.google.inject.PrivateBinder;
import com.google.inject.Provider;
import com.google.inject.Provides;
import com.google.inject.internal.ProvisionListenerStackCallback.ProvisionCallback;
import com.google.inject.internal.util.StackTraceElements;
import com.google.inject.spi.BindingTargetVisitor;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.HasDependencies;
import com.google.inject.spi.InjectionPoint;
import com.google.inject.spi.ProviderInstanceBinding;
import com.google.inject.spi.ProviderWithExtensionVisitor;
import com.google.inject.spi.ProvidesMethodBinding;
import com.google.inject.spi.ProvidesMethodTargetVisitor;
import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.List;
import java.util.Set;
/**
* A provider that invokes a method and returns its result.
*
* @author [email protected] (Jesse Wilson)
*/
public abstract class ProviderMethod implements ProviderWithExtensionVisitor, HasDependencies,
ProvidesMethodBinding {
/**
* Creates a {@link ProviderMethod}.
*
* Unless {@code skipFastClassGeneration} is set, this will use
* {@link net.sf.cglib.reflect.FastClass} to invoke the actual method, since it is significantly
* faster. However, this will fail if the method is {@code private} or {@code protected}, since
* fastclass is subject to java access policies.
*/
static ProviderMethod create(Key key, Method method, Object instance,
ImmutableSet> dependencies, List> parameterProviders,
Class scopeAnnotation, boolean skipFastClassGeneration,
Annotation annotation) {
int modifiers = method.getModifiers();
/*if[AOP]*/
if (!skipFastClassGeneration) {
try {
net.sf.cglib.reflect.FastClass fc = BytecodeGen.newFastClassForMember(method);
if (fc != null) {
return new FastClassProviderMethod(key,
fc,
method,
instance,
dependencies,
parameterProviders,
scopeAnnotation,
annotation);
}
} catch (net.sf.cglib.core.CodeGenerationException e) {/* fall-through */}
}
/*end[AOP]*/
if (!Modifier.isPublic(modifiers) ||
!Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
method.setAccessible(true);
}
return new ReflectionProviderMethod(key,
method,
instance,
dependencies,
parameterProviders,
scopeAnnotation,
annotation);
}
protected final Object instance;
protected final Method method;
private final Key key;
private final Class scopeAnnotation;
private final ImmutableSet> dependencies;
private final List> parameterProviders;
private final boolean exposed;
private final Annotation annotation;
/**
* @param method the method to invoke. It's return type must be the same type as {@code key}.
*/
private ProviderMethod(Key key, Method method, Object instance,
ImmutableSet> dependencies, List> parameterProviders,
Class scopeAnnotation, Annotation annotation) {
this.key = key;
this.scopeAnnotation = scopeAnnotation;
this.instance = instance;
this.dependencies = dependencies;
this.method = method;
this.parameterProviders = parameterProviders;
this.exposed = method.isAnnotationPresent(Exposed.class);
this.annotation = annotation;
}
@Override
public Key getKey() {
return key;
}
@Override
public Method getMethod() {
return method;
}
// exposed for GIN
public Object getInstance() {
return instance;
}
@Override
public Object getEnclosingInstance() {
return instance;
}
@Override
public Annotation getAnnotation() {
return annotation;
}
public void configure(Binder binder) {
binder = binder.withSource(method);
if (scopeAnnotation != null) {
binder.bind(key).toProvider(this).in(scopeAnnotation);
} else {
binder.bind(key).toProvider(this);
}
if (exposed) {
// the cast is safe 'cause the only binder we have implements PrivateBinder. If there's a
// misplaced @Exposed, calling this will add an error to the binder's error queue
((PrivateBinder) binder).expose(key);
}
}
@Override
public T get() {
Object[] parameters = new Object[parameterProviders.size()];
for (int i = 0; i < parameters.length; i++) {
parameters[i] = parameterProviders.get(i).get();
}
try {
return doProvision(parameters);
} catch (IllegalAccessException e) {
throw new AssertionError(e);
} catch (InvocationTargetException e) {
throw Exceptions.rethrowCause(e);
}
}
/** Extension point for our subclasses to implement the provisioning strategy. */
abstract T doProvision(Object[] parameters)
throws IllegalAccessException, InvocationTargetException;
@Override
public Set> getDependencies() {
return dependencies;
}
@Override
@SuppressWarnings("unchecked")
public V acceptExtensionVisitor(BindingTargetVisitor visitor,
ProviderInstanceBinding binding) {
if (visitor instanceof ProvidesMethodTargetVisitor) {
return ((ProvidesMethodTargetVisitor)visitor).visit(this);
}
return visitor.visit(binding);
}
@Override public String toString() {
String annotationString = annotation.toString();
// Show @Provides w/o the com.google.inject prefix.
if (annotation.annotationType() == Provides.class) {
annotationString = "@Provides";
} else if (annotationString.endsWith("()")) {
// Remove the common "()" suffix if there are no values.
annotationString = annotationString.substring(0, annotationString.length() - 2);
}
return annotationString + " " + StackTraceElements.forMember(method);
}
@Override
public boolean equals(Object obj) {
if (obj instanceof ProviderMethod) {
ProviderMethod o = (ProviderMethod) obj;
return method.equals(o.method)
&& instance.equals(o.instance)
&& annotation.equals(o.annotation);
} else {
return false;
}
}
@Override
public int hashCode() {
// Avoid calling hashCode on 'instance', which is a user-object
// that might not be expecting it.
// (We need to call equals, so we do. But we can avoid hashCode.)
return Objects.hashCode(method, annotation);
}
/*if[AOP]*/
/**
* A {@link ProviderMethod} implementation that uses {@link net.sf.cglib.reflect.FastClass#invoke}
* to invoke the provider method.
*/
private static final class FastClassProviderMethod extends ProviderMethod {
final net.sf.cglib.reflect.FastClass fastClass;
final int methodIndex;
FastClassProviderMethod(Key key,
net.sf.cglib.reflect.FastClass fc,
Method method,
Object instance,
ImmutableSet> dependencies,
List> parameterProviders,
Class scopeAnnotation,
Annotation annotation) {
super(key,
method,
instance,
dependencies,
parameterProviders,
scopeAnnotation,
annotation);
this.fastClass = fc;
this.methodIndex = fc.getMethod(method).getIndex();
}
@SuppressWarnings("unchecked")
@Override
public T doProvision(Object[] parameters)
throws IllegalAccessException, InvocationTargetException {
return (T) fastClass.invoke(methodIndex, instance, parameters);
}
}
/*end[AOP]*/
/**
* A {@link ProviderMethod} implementation that invokes the method using normal java reflection.
*/
private static final class ReflectionProviderMethod extends ProviderMethod {
ReflectionProviderMethod(Key key,
Method method,
Object instance,
ImmutableSet> dependencies,
List> parameterProviders,
Class scopeAnnotation,
Annotation annotation) {
super(key,
method,
instance,
dependencies,
parameterProviders,
scopeAnnotation,
annotation);
}
@SuppressWarnings("unchecked")
@Override
T doProvision(Object[] parameters) throws IllegalAccessException, InvocationTargetException {
return (T) method.invoke(instance, parameters);
}
}
static BindingImpl createBinding(
InjectorImpl injector,
Key key,
ProviderMethod providerMethod,
Object source,
Scoping scoping) {
Factory factory = new Factory(source, providerMethod);
InternalFactory scopedFactory =
Scoping.scope(key, injector, factory, source, scoping);
return new ProviderMethodProviderInstanceBindingImpl(
injector, key, source, scopedFactory, scoping, providerMethod, factory);
}
private static final class ProviderMethodProviderInstanceBindingImpl
extends ProviderInstanceBindingImpl implements DelayedInitialize {
final Factory factory;
ProviderMethodProviderInstanceBindingImpl(
InjectorImpl injector,
Key key,
Object source,
InternalFactory internalFactory,
Scoping scoping,
// TODO(lukes): it is a little strange that we expose the ProviderMethod as the
// userProvider. Maybe we should expose BindingImpl.getProvider() and then we could drop
// the ProviderLookups stored by ProviderMethod. It probably isn't a big deal either way
// but having 2 ways to invoke the method is kind of weird.
ProviderMethod providerInstance,
Factory factory) {
super(
injector,
key,
source,
internalFactory,
scoping,
providerInstance,
ImmutableSet.of());
this.factory = factory;
}
@Override
public void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
factory.parameterInjectors =
injector.getParametersInjectors(factory.providerMethod.dependencies.asList(), errors);
factory.provisionCallback = injector.provisionListenerStore.get(this);
}
}
private static final class Factory implements InternalFactory {
private final Object source;
private final ProviderMethod providerMethod;
private ProvisionListenerStackCallback provisionCallback;
private SingleParameterInjector[] parameterInjectors;
Factory(Object source, ProviderMethod providerMethod) {
this.source = source;
this.providerMethod = providerMethod;
}
@Override
public T get(
final Errors errors,
final InternalContext context,
final Dependency dependency,
boolean linked)
throws ErrorsException {
final ConstructionContext constructionContext = context.getConstructionContext(this);
// We have a circular reference between bindings. Return a proxy.
if (constructionContext.isConstructing()) {
Class expectedType = dependency.getKey().getTypeLiteral().getRawType();
// TODO: if we can't proxy this object, can we proxy the other object?
@SuppressWarnings("unchecked")
T proxyType =
(T) constructionContext.createProxy(errors, context.getInjectorOptions(), expectedType);
return proxyType;
}
// Optimization: Don't go through the callback stack if no one's listening.
constructionContext.startConstruction();
try {
if (!provisionCallback.hasListeners()) {
return provision(errors, dependency, context, constructionContext);
} else {
return provisionCallback.provision(
errors,
context,
new ProvisionCallback() {
@Override
public T call() throws ErrorsException {
return provision(errors, dependency, context, constructionContext);
}
});
}
} finally {
constructionContext.removeCurrentReference();
constructionContext.finishConstruction();
}
}
T provision(
Errors errors,
Dependency dependency,
InternalContext context,
ConstructionContext constructionContext)
throws ErrorsException {
try {
T t = providerMethod.doProvision(
SingleParameterInjector.getAll(errors, context, parameterInjectors));
errors.checkForNull(t, providerMethod.getMethod(), dependency);
constructionContext.setProxyDelegates(t);
return t;
} catch (IllegalAccessException e) {
throw new AssertionError(e);
} catch (InvocationTargetException userException) {
Throwable cause =
userException.getCause() != null ? userException.getCause() : userException;
throw errors
.withSource(source)
.errorInProvider(cause)
.toException();
}
}
@Override
public String toString() {
return providerMethod.toString();
}
}
}