| /** |
| * 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.common.collect.ImmutableList; |
| import com.google.common.collect.Lists; |
| import com.google.common.collect.Maps; |
| import com.google.inject.Key; |
| import com.google.inject.spi.Dependency; |
| import com.google.inject.spi.DependencyAndSource; |
| |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Internal context. Used to coordinate injections and support circular |
| * dependencies. |
| * |
| * @author crazybob@google.com (Bob Lee) |
| */ |
| final class InternalContext { |
| |
| private Map<Object, ConstructionContext<?>> constructionContexts = Maps.newHashMap(); |
| |
| /** 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. */ |
| private final DependencyStack state = new DependencyStack(); |
| |
| @SuppressWarnings("unchecked") |
| public <T> ConstructionContext<T> getConstructionContext(Object key) { |
| ConstructionContext<T> constructionContext |
| = (ConstructionContext<T>) constructionContexts.get(key); |
| if (constructionContext == null) { |
| constructionContext = new ConstructionContext<T>(); |
| constructionContexts.put(key, constructionContext); |
| } |
| return constructionContext; |
| } |
| |
| public Dependency<?> getDependency() { |
| return dependency; |
| } |
| |
| /** Sets the new current dependency & adds it to the state. */ |
| public Dependency<?> pushDependency(Dependency<?> dependency, Object source) { |
| Dependency<?> previous = this.dependency; |
| this.dependency = dependency; |
| state.add(dependency, source); |
| return previous; |
| } |
| |
| /** Pops the current state & sets the new dependency. */ |
| public void popStateAndSetDependency(Dependency<?> newDependency) { |
| state.pop(); |
| this.dependency = newDependency; |
| } |
| |
| /** Adds to the state without setting the dependency. */ |
| public void pushState(Key<?> key, Object source) { |
| state.add(key, source); |
| } |
| |
| /** Pops from the state without setting a dependency. */ |
| public void popState() { |
| state.pop(); |
| } |
| |
| /** Returns the current dependency chain (all the state). */ |
| public List<DependencyAndSource> getDependencyChain() { |
| ImmutableList.Builder<DependencyAndSource> builder = ImmutableList.builder(); |
| for (int i = 0; i < state.size(); i += 2) { |
| Object evenEntry = state.get(i); |
| Dependency<?> dependency; |
| if (evenEntry instanceof Key) { |
| dependency = Dependency.get((Key<?>) evenEntry); |
| } else { |
| dependency = (Dependency<?>) evenEntry; |
| } |
| builder.add(new DependencyAndSource(dependency, state.get(i + 1))); |
| } |
| return builder.build(); |
| } |
| |
| /** |
| * Keeps track of the hierarchy of types needed during injection. |
| * |
| * <p>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 static final class DependencyStack { |
| private Object[] elements = new Object[16]; |
| private int size = 0; |
| |
| public void add(Object dependencyOrKey, Object source) { |
| if (elements.length < size + 2) { |
| elements = Arrays.copyOf(elements, (elements.length*3)/2 + 2); |
| } |
| elements[size++] = dependencyOrKey; |
| elements[size++] = source; |
| } |
| |
| public void pop() { |
| elements[--size] = null; |
| elements[--size] = null; |
| } |
| |
| public Object get(int i) { |
| return elements[i]; |
| } |
| |
| public int size() { |
| return size; |
| } |
| } |
| } |