/**
* Copyright (C) 2010 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.throwingproviders;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.inject.Binder;
import com.google.inject.Key;
import com.google.inject.Module;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.Annotations;
import com.google.inject.internal.Errors;
import com.google.inject.internal.UniqueAnnotations;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.Message;
import com.google.inject.util.Modules;
import java.lang.annotation.Annotation;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.List;
import java.util.logging.Logger;
/**
* Creates bindings to methods annotated with {@literal @}{@link CheckedProvides}. Use the scope
* and binding annotations on the provider method to configure the binding.
*
* @author sameb@google.com (Sam Berlin)
*/
final class CheckedProviderMethodsModule implements Module {
private final Object delegate;
private final TypeLiteral<?> typeLiteral;
private CheckedProviderMethodsModule(Object delegate) {
this.delegate = checkNotNull(delegate, "delegate");
this.typeLiteral = TypeLiteral.get(this.delegate.getClass());
}
/**
* Returns a module which creates bindings for provider methods from the given module.
*/
static Module forModule(Module module) {
// avoid infinite recursion, since installing a module always installs itself
if (module instanceof CheckedProviderMethodsModule) {
return Modules.EMPTY_MODULE;
}
return new CheckedProviderMethodsModule(module);
}
public synchronized void configure(Binder binder) {
for (CheckedProviderMethod<?> throwingProviderMethod : getProviderMethods(binder)) {
throwingProviderMethod.configure(binder);
}
}
List<CheckedProviderMethod<?>> getProviderMethods(Binder binder) {
List<CheckedProviderMethod<?>> result = Lists.newArrayList();
for (Class<?> c = delegate.getClass(); c != Object.class; c = c.getSuperclass()) {
for (Method method : c.getDeclaredMethods()) {
CheckedProvides checkedProvides = method.getAnnotation(CheckedProvides.class);
if(checkedProvides != null) {
result.add(createProviderMethod(binder, method, checkedProvides.value()));
}
}
}
return result;
}
<T> CheckedProviderMethod<T> createProviderMethod(Binder binder, final Method method,
Class<? extends CheckedProvider> throwingProvider) {
binder = binder.withSource(method);
Errors errors = new Errors(method);
// prepare the parameter providers
List<Dependency<?>> dependencies = Lists.newArrayList();
List<Provider<?>> parameterProviders = Lists.newArrayList();
List<TypeLiteral<?>> parameterTypes = typeLiteral.getParameterTypes(method);
Annotation[][] parameterAnnotations = method.getParameterAnnotations();
for (int i = 0; i < parameterTypes.size(); i++) {
Key<?> key = getKey(errors, parameterTypes.get(i), method, parameterAnnotations[i]);
if(key.equals(Key.get(Logger.class))) {
// If it was a Logger, change the key to be unique & bind it to a
// provider that provides a logger with a proper name.
// This solves issue 482 (returning a new anonymous logger on every call exhausts memory)
Key<Logger> loggerKey = Key.get(Logger.class, UniqueAnnotations.create());
binder.bind(loggerKey).toProvider(new LogProvider(method));
key = loggerKey;
}
dependencies.add(Dependency.get(key));
parameterProviders.add(binder.getProvider(key));
}
@SuppressWarnings("unchecked") // Define T as the method's return type.
TypeLiteral<T> returnType = (TypeLiteral<T>) typeLiteral.getReturnType(method);
List<TypeLiteral<?>> exceptionTypes = typeLiteral.getExceptionTypes(method);
Key<T> key = getKey(errors, returnType, method, method.getAnnotations());
Class<? extends Annotation> scopeAnnotation
= Annotations.findScopeAnnotation(errors, method.getAnnotations());
for (Message message : errors.getMessages()) {
binder.addError(message);
}
return new CheckedProviderMethod<T>(key, method, delegate, ImmutableSet.copyOf(dependencies),
parameterProviders, scopeAnnotation, throwingProvider, exceptionTypes);
}
<T> Key<T> getKey(Errors errors, TypeLiteral<T> type, Member member, Annotation[] annotations) {
Annotation bindingAnnotation = Annotations.findBindingAnnotation(errors, member, annotations);
return bindingAnnotation == null ? Key.get(type) : Key.get(type, bindingAnnotation);
}
@Override public boolean equals(Object o) {
return o instanceof CheckedProviderMethodsModule
&& ((CheckedProviderMethodsModule) o).delegate == delegate;
}
@Override public int hashCode() {
return delegate.hashCode();
}
/** A provider that returns a logger based on the method name. */
private static final class LogProvider implements Provider<Logger> {
private final String name;
public LogProvider(Method method) {
this.name = method.getDeclaringClass().getName() + "." + method.getName();
}
public Logger get() {
return Logger.getLogger(name);
}
}
}