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Java example source code file (MembersInjectorImpl.java)

This example Java source code file (MembersInjectorImpl.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

errors, errorsexception, immutablelist, immutableset, injectionlistener, internalcontext, membersinjector, membersinjectorimpl, override, runtimeexception, singlememberinjector, string, typeliteral

The MembersInjectorImpl.java Java example source code

/**
 * Copyright (C) 2009 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.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.inject.Key;
import com.google.inject.MembersInjector;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.ProvisionListenerStackCallback.ProvisionCallback;
import com.google.inject.spi.InjectionListener;
import com.google.inject.spi.InjectionPoint;

/**
 * Injects members of instances of a given type.
 *
 * @author jessewilson@google.com (Jesse Wilson)
 */
final class MembersInjectorImpl<T> implements MembersInjector {
  private final TypeLiteral<T> typeLiteral;
  private final InjectorImpl injector;
  private final ImmutableList<SingleMemberInjector> memberInjectors;
  private final ImmutableSet<MembersInjector userMembersInjectors;
  private final ImmutableSet<InjectionListener injectionListeners;
  /*if[AOP]*/
  private final ImmutableList<MethodAspect> addedAspects;
  /*end[AOP]*/

  MembersInjectorImpl(InjectorImpl injector, TypeLiteral<T> typeLiteral,
      EncounterImpl<T> encounter, ImmutableList memberInjectors) {
    this.injector = injector;
    this.typeLiteral = typeLiteral;
    this.memberInjectors = memberInjectors;
    this.userMembersInjectors = encounter.getMembersInjectors();
    this.injectionListeners = encounter.getInjectionListeners();
    /*if[AOP]*/
    this.addedAspects = encounter.getAspects();
    /*end[AOP]*/
  }

  public ImmutableList<SingleMemberInjector> getMemberInjectors() {
    return memberInjectors;
  }

  public void injectMembers(T instance) {
    Errors errors = new Errors(typeLiteral);
    try {
      injectAndNotify(instance, errors, null, null, typeLiteral, false);
    } catch (ErrorsException e) {
      errors.merge(e.getErrors());
    }

    errors.throwProvisionExceptionIfErrorsExist();
  }

  void injectAndNotify(final T instance,
      final Errors errors,
      final Key<T> key, // possibly null!
      final ProvisionListenerStackCallback<T> provisionCallback, // possibly null!
      final Object source,
      final boolean toolableOnly) throws ErrorsException {
    if (instance == null) {
      return;
    }

    injector.callInContext(new ContextualCallable<Void>() {
      @Override
      public Void call(final InternalContext context) throws ErrorsException {
        context.pushState(key, source);
        try {
          if (provisionCallback != null && provisionCallback.hasListeners()) {
            provisionCallback.provision(errors, context, new ProvisionCallback<T>() {
              @Override public T call() {
                injectMembers(instance, errors, context, toolableOnly);
                return instance;
              }
            });
          } else {
            injectMembers(instance, errors, context, toolableOnly);
          }
        } finally {
          context.popState();
        }
        return null;
      }
    });

    // TODO: We *could* notify listeners too here,
    // but it's not clear if we want to.  There's no way to know
    // if a MembersInjector from the usersMemberInjector list wants
    // toolable injections, so do we really want to notify
    // about injection?  (We could take a strategy of only notifying
    // if atleast one InjectionPoint was toolable, in which case
    // the above callInContext could return 'true' if it injected
    // anything.)
    if(!toolableOnly) {
      notifyListeners(instance, errors);
    }
  }

  void notifyListeners(T instance, Errors errors) throws ErrorsException {
    int numErrorsBefore = errors.size();
    for (InjectionListener<? super T> injectionListener : injectionListeners) {
      try {
        injectionListener.afterInjection(instance);
      } catch (RuntimeException e) {
        errors.errorNotifyingInjectionListener(injectionListener, typeLiteral, e);
      }
    }
    errors.throwIfNewErrors(numErrorsBefore);
  }

  void injectMembers(T t, Errors errors, InternalContext context, boolean toolableOnly) {
    // optimization: use manual for/each to save allocating an iterator here
    for (int i = 0, size = memberInjectors.size(); i < size; i++) {
      SingleMemberInjector injector = memberInjectors.get(i);
      if(!toolableOnly || injector.getInjectionPoint().isToolable()) {
        injector.inject(errors, context, t);
      }
    }

    // TODO: There's no way to know if a user's MembersInjector wants toolable injections.
    if(!toolableOnly) {
      for (MembersInjector<? super T> userMembersInjector : userMembersInjectors) {
        try {
          userMembersInjector.injectMembers(t);
        } catch (RuntimeException e) {
          errors.errorInUserInjector(userMembersInjector, typeLiteral, e);
        }
      }
    }
  }

  @Override public String toString() {
    return "MembersInjector<" + typeLiteral + ">";
  }

  public ImmutableSet<InjectionPoint> getInjectionPoints() {
    ImmutableSet.Builder<InjectionPoint> builder = ImmutableSet.builder();
    for (SingleMemberInjector memberInjector : memberInjectors) {
      builder.add(memberInjector.getInjectionPoint());
    }
    return builder.build();
  }

  /*if[AOP]*/
  public ImmutableList<MethodAspect> getAddedAspects() {
    return addedAspects;
  }
  /*end[AOP]*/
}

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