dagger.internal.SetFactory Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of dagger Show documentation
Show all versions of dagger Show documentation
A fast dependency injector for Android and Java.
/*
* Copyright (C) 2014 The Dagger Authors.
*
* 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 dagger.internal;
import static dagger.internal.DaggerCollections.hasDuplicates;
import static dagger.internal.DaggerCollections.newHashSetWithExpectedSize;
import static dagger.internal.DaggerCollections.presizedList;
import static dagger.internal.Preconditions.checkNotNull;
import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableSet;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import javax.inject.Provider;
/**
* A {@link Factory} implementation used to implement {@link Set} bindings. This factory always
* returns a new {@link Set} instance for each call to {@link #get} (as required by {@link Factory})
* whose elements are populated by subsequent calls to their {@link Provider#get} methods.
*
* @author Gregory Kick
* @since 2.0
*/
public final class SetFactory implements Factory> {
private static final Factory> EMPTY_FACTORY = InstanceFactory.create(emptySet());
@SuppressWarnings({"unchecked", "rawtypes"}) // safe covariant cast
public static Factory> empty() {
return (Factory) EMPTY_FACTORY;
}
/**
* Constructs a new {@link Builder} for a {@link SetFactory} with {@code individualProviderSize}
* individual {@code Provider} and {@code collectionProviderSize} {@code
* Provider>} instances.
*/
public static Builder builder(int individualProviderSize, int collectionProviderSize) {
return new Builder(individualProviderSize, collectionProviderSize);
}
/**
* A builder to accumulate {@code Provider} and {@code Provider>} instances.
* These are only intended to be single-use and from within generated code. Do NOT add
* providers after calling {@link #build()}.
*/
public static final class Builder {
private final List> individualProviders;
private final List>> collectionProviders;
private Builder(int individualProviderSize, int collectionProviderSize) {
individualProviders = presizedList(individualProviderSize);
collectionProviders = presizedList(collectionProviderSize);
}
@SuppressWarnings("unchecked")
public Builder addProvider(Provider individualProvider) {
assert individualProvider != null : "Codegen error? Null provider";
// TODO(ronshapiro): Store a List> and avoid the cast to Provider
individualProviders.add((Provider) individualProvider);
return this;
}
@SuppressWarnings("unchecked")
public Builder addCollectionProvider(
Provider> collectionProvider) {
assert collectionProvider != null : "Codegen error? Null provider";
collectionProviders.add((Provider>) collectionProvider);
return this;
}
public SetFactory build() {
assert !hasDuplicates(individualProviders)
: "Codegen error? Duplicates in the provider list";
assert !hasDuplicates(collectionProviders)
: "Codegen error? Duplicates in the provider list";
return new SetFactory(individualProviders, collectionProviders);
}
}
private final List> individualProviders;
private final List>> collectionProviders;
private SetFactory(
List> individualProviders, List>> collectionProviders) {
this.individualProviders = individualProviders;
this.collectionProviders = collectionProviders;
}
/**
* Returns a {@link Set} whose iteration order is that of the elements given by each of the
* providers, which are invoked in the order given at creation.
*
* @throws NullPointerException if any of the delegate {@link Set} instances or elements therein
* are {@code null}
*/
@Override
public Set get() {
int size = individualProviders.size();
// Profiling revealed that this method was a CPU-consuming hotspot in some applications, so
// these loops were changed to use c-style for. Versus enhanced for-each loops, C-style for is
// faster for ArrayLists, at least through Java 8.
List> providedCollections =
new ArrayList>(collectionProviders.size());
for (int i = 0, c = collectionProviders.size(); i < c; i++) {
Collection providedCollection = collectionProviders.get(i).get();
size += providedCollection.size();
providedCollections.add(providedCollection);
}
Set providedValues = newHashSetWithExpectedSize(size);
for (int i = 0, c = individualProviders.size(); i < c; i++) {
providedValues.add(checkNotNull(individualProviders.get(i).get()));
}
for (int i = 0, c = providedCollections.size(); i < c; i++) {
for (T element : providedCollections.get(i)) {
providedValues.add(checkNotNull(element));
}
}
return unmodifiableSet(providedValues);
}
}