com.google.inject.internal.InternalContext Maven / Gradle / Ivy
/*
* Copyright (C) 2006 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.inject.internal.InjectorImpl.InjectorOptions;
import com.google.inject.spi.Dependency;
import java.util.IdentityHashMap;
import java.util.Map;
/**
* Internal context. Used to coordinate injections and support circular dependencies.
*
* @author [email protected] (Bob Lee)
*/
final class InternalContext implements AutoCloseable {
private final InjectorOptions options;
private final Map> constructionContexts =
new IdentityHashMap>();
/** Keeps track of the type that is currently being requested for injection. */
private Dependency dependency;
/**
* Keeps track of the hierarchy of types needed during injection.
*
* This is a pairwise combination of dependencies and sources, with dependencies or keys on
* even indices, and sources on odd indices. This structure is to avoid the memory overhead of
* DependencyAndSource objects, which can add to several tens of megabytes in large applications.
*/
private Object[] dependencyStack = new Object[16];
private int dependencyStackSize = 0;
/**
* The number of times {@link #enter()} has been called + 1 for initial construction. This value
* is decremented when {@link #exit()} is called.
*/
private int enterCount;
/**
* A single element array to clear when the {@link #enterCount} hits {@code 0}.
*
*
This is the value stored in the {@code InjectorImpl.localContext} thread local.
*/
private final Object[] toClear;
InternalContext(InjectorOptions options, Object[] toClear) {
this.options = options;
this.toClear = toClear;
this.enterCount = 1;
}
/** Should only be called by InjectorImpl.enterContext(). */
void enter() {
enterCount++;
}
/** Should be called any any method that received an instance via InjectorImpl.enterContext(). */
@Override
public void close() {
int newCount = --enterCount;
if (newCount < 0) {
throw new IllegalStateException("Called close() too many times");
}
if (newCount == 0) {
toClear[0] = null;
}
}
InjectorOptions getInjectorOptions() {
return options;
}
@SuppressWarnings("unchecked")
ConstructionContext getConstructionContext(Object key) {
ConstructionContext constructionContext =
(ConstructionContext) constructionContexts.get(key);
if (constructionContext == null) {
constructionContext = new ConstructionContext<>();
constructionContexts.put(key, constructionContext);
}
return constructionContext;
}
Dependency getDependency() {
return dependency;
}
/** Sets the new current dependency & adds it to the state. */
Dependency pushDependency(Dependency dependency, Object source) {
Dependency previous = this.dependency;
this.dependency = dependency;
doPushState(dependency, source);
return previous;
}
/** Pops the current state & sets the new dependency. */
void popStateAndSetDependency(Dependency newDependency) {
popState();
this.dependency = newDependency;
}
/** Adds to the state without setting the dependency. */
void pushState(com.google.inject.Key key, Object source) {
doPushState(key, source);
}
private void doPushState(Object dependencyOrKey, Object source) {
int localSize = dependencyStackSize;
Object[] localStack = dependencyStack;
if (localStack.length < localSize + 2) {
localStack = dependencyStack =
java.util.Arrays.copyOf(localStack, (localStack.length * 3) / 2 + 2);
}
localStack[localSize++] = dependencyOrKey;
localStack[localSize++] = source;
dependencyStackSize = localSize;
}
/** Pops from the state without setting a dependency. */
void popState() {
// N.B. we don't null out the array entries. It isn't necessary since all the objects in the
// array (Key, Dependency, or Binding source objects) are all tied to the lifetime of the
// injector, which is greater than the lifetime of this object. So removing them from the array
// doesn't matter.
dependencyStackSize -= 2;
}
/** Returns the current dependency chain (all the state stored in the dependencyStack). */
java.util.List getDependencyChain() {
com.google.common.collect.ImmutableList.Builder
builder = com.google.common.collect.ImmutableList.builder();
for (int i = 0; i < dependencyStackSize; i += 2) {
Object evenEntry = dependencyStack[i];
Dependency dependency;
if (evenEntry instanceof com.google.inject.Key) {
dependency = Dependency.get((com.google.inject.Key) evenEntry);
} else {
dependency = (Dependency) evenEntry;
}
builder.add(new com.google.inject.spi.DependencyAndSource(dependency, dependencyStack[i + 1]));
}
return builder.build();
}
}