55 lines
1.6 KiB
Java
55 lines
1.6 KiB
Java
/*
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* Copyright (C) 2016 The Dagger Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dagger.internal;
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import static dagger.internal.Preconditions.checkNotNull;
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import dagger.Lazy;
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import javax.inject.Provider;
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/**
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* A {@link Provider} of {@link Lazy} instances that each delegate to a given {@link Provider}.
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*/
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public final class ProviderOfLazy<T> implements Provider<Lazy<T>> {
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private final Provider<T> provider;
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private ProviderOfLazy(Provider<T> provider) {
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assert provider != null;
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this.provider = provider;
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}
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/**
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* Returns a new instance of {@link Lazy Lazy<T>}, which calls {@link Provider#get()} at
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* most once on the {@link Provider} held by this object.
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*/
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@Override
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public Lazy<T> get() {
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return DoubleCheck.lazy(provider);
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}
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/**
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* Creates a new {@link Provider Provider<Lazy<T>>} that decorates the given
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* {@link Provider}.
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*
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* @see #get()
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*/
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public static <T> Provider<Lazy<T>> create(Provider<T> provider) {
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return new ProviderOfLazy<T>(checkNotNull(provider));
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}
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}
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