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/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.common.inject;
import org.opensearch.common.inject.internal.Errors;
import org.opensearch.common.inject.internal.ErrorsException;
import org.opensearch.common.inject.spi.InjectionPoint;
import java.util.ArrayList;
import java.util.IdentityHashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
/**
* Manages and injects instances at injector-creation time. This is made more complicated by
* instances that request other instances while they're being injected. We overcome this by using
* {@link Initializable}, which attempts to perform injection before use.
*
* @author [email protected] (Jesse Wilson)
*
* @opensearch.internal
*/
class Initializer {
/**
* the only thread that we'll use to inject members.
*/
private final Thread creatingThread = Thread.currentThread();
/**
* zero means everything is injected.
*/
private final CountDownLatch ready = new CountDownLatch(1);
/**
* Maps instances that need injection to a source that registered them
*/
private final Map> pendingInjection = new IdentityHashMap<>();
/**
* Registers an instance for member injection when that step is performed.
*
* @param instance an instance that optionally has members to be injected (each annotated with
* @param source the source location that this injection was requested
* @Inject).
*/
public Initializable requestInjection(InjectorImpl injector, T instance, Object source, Set injectionPoints) {
Objects.requireNonNull(source);
// short circuit if the object has no injections
if (instance == null || (injectionPoints.isEmpty() && !injector.membersInjectorStore.hasTypeListeners())) {
return Initializables.of(instance);
}
InjectableReference initializable = new InjectableReference<>(injector, instance, source);
pendingInjection.put(instance, initializable);
return initializable;
}
/**
* Prepares member injectors for all injected instances. This prompts Guice to do static analysis
* on the injected instances.
*/
void validateOustandingInjections(Errors errors) {
for (InjectableReference reference : pendingInjection.values()) {
try {
reference.validate(errors);
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
}
}
/**
* Performs creation-time injections on all objects that require it. Whenever fulfilling an
* injection depends on another object that requires injection, we inject it first. If the two
* instances are codependent (directly or transitively), ordering of injection is arbitrary.
*/
void injectAll(final Errors errors) {
// loop over a defensive copy since ensureInjected() mutates the set. Unfortunately, that copy
// is made complicated by a bug in IBM's JDK, wherein entrySet().toArray(Object[]) doesn't work
for (InjectableReference reference : new ArrayList<>(pendingInjection.values())) {
try {
reference.get(errors);
} catch (ErrorsException e) {
errors.merge(e.getErrors());
}
}
if (!pendingInjection.isEmpty()) {
throw new AssertionError("Failed to satisfy " + pendingInjection);
}
ready.countDown();
}
private class InjectableReference implements Initializable {
private final InjectorImpl injector;
private final T instance;
private final Object source;
private MembersInjectorImpl membersInjector;
InjectableReference(InjectorImpl injector, T instance, Object source) {
this.injector = injector;
this.instance = Objects.requireNonNull(instance, "instance");
this.source = Objects.requireNonNull(source, "source");
}
public void validate(Errors errors) throws ErrorsException {
@SuppressWarnings("unchecked") // the type of 'T' is a TypeLiteral
TypeLiteral type = TypeLiteral.get((Class) instance.getClass());
membersInjector = injector.membersInjectorStore.get(type, errors.withSource(source));
}
/**
* Reentrant. If {@code instance} was registered for injection at injector-creation time, this
* method will ensure that all its members have been injected before returning.
*/
@Override
public T get(Errors errors) throws ErrorsException {
if (ready.getCount() == 0) {
return instance;
}
// just wait for everything to be injected by another thread
if (Thread.currentThread() != creatingThread) {
try {
ready.await();
return instance;
} catch (InterruptedException e) {
// Give up, since we don't know if our injection is ready
throw new RuntimeException(e);
}
}
// toInject needs injection, do it right away. we only do this once, even if it fails
if (pendingInjection.remove(instance) != null) {
membersInjector.injectAndNotify(instance, errors.withSource(source));
}
return instance;
}
@Override
public String toString() {
return instance.toString();
}
}
}