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/*
 * 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.Provides;
import com.google.inject.internal.InternalProviderInstanceBindingImpl.InitializationTiming;
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.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.Set;

/**
 * A provider that invokes a method and returns its result.
 *
 * @author [email protected] (Jesse Wilson)
 */
public abstract class ProviderMethod extends InternalProviderInstanceBindingImpl.CyclicFactory
    implements HasDependencies, ProvidesMethodBinding, ProviderWithExtensionVisitor {

  /**
   * 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, 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, 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, scopeAnnotation, annotation); } protected final Object instance; protected final Method method; private final Key key; private final Class scopeAnnotation; private final ImmutableSet> dependencies; private final boolean exposed; private final Annotation annotation; /** * Set by {@link #initialize(InjectorImpl, Errors)} so it is always available prior to injection. */ private SingleParameterInjector[] parameterInjectors; /** @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, Class scopeAnnotation, Annotation annotation) { // We can be safely initialized eagerly since our bindings must exist statically and it is an // error for them not to. super(InitializationTiming.EAGER); this.key = key; this.scopeAnnotation = scopeAnnotation; this.instance = instance; this.dependencies = dependencies; this.method = method; 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 void initialize(InjectorImpl injector, Errors errors) throws ErrorsException { parameterInjectors = injector.getParametersInjectors(dependencies.asList(), errors); } @Override protected T doProvision(InternalContext context, Dependency dependency) throws InternalProvisionException { try { T t = doProvision(SingleParameterInjector.getAll(context, parameterInjectors)); if (t == null && !dependency.isNullable()) { InternalProvisionException.onNullInjectedIntoNonNullableDependency(getMethod(), dependency); } return t; } catch (IllegalAccessException e) { throw new AssertionError(e); } catch (InvocationTargetException userException) { Throwable cause = userException.getCause() != null ? userException.getCause() : userException; throw InternalProvisionException.errorInProvider(cause).addSource(getSource()); } } /** 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, Class scopeAnnotation, Annotation annotation) { super(key, method, instance, dependencies, 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, Class scopeAnnotation, Annotation annotation) { super(key, method, instance, dependencies, scopeAnnotation, annotation); } @SuppressWarnings("unchecked") @Override T doProvision(Object[] parameters) throws IllegalAccessException, InvocationTargetException { return (T) method.invoke(instance, parameters); } } }





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