61 lines
2.2 KiB
Java
61 lines
2.2 KiB
Java
/*
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* Copyright 2020 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* https://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, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.buffer.api;
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import java.util.ArrayDeque;
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/**
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* A scope is a convenient mechanism for capturing the life cycles of multiple reference counted objects. Once the scope
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* is closed, all the added objects will also be closed in reverse insert order. That is, the most recently added
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* object will be closed first.
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* <p>
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* Scopes can be reused. After a scope has been closed, new objects can be added to it, and they will be closed when the
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* scope is closed again.
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* <p>
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* Objects will not be closed multiple times if the scope is closed multiple times, unless said objects are also added
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* multiple times.
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* <p>
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* Note that scopes are not thread-safe. They are intended to be used from a single thread.
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*/
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public final class Scope implements AutoCloseable {
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private final ArrayDeque<Resource<?>> deque = new ArrayDeque<>();
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/**
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* Add the given reference counted object to this scope, so that it will be {@linkplain Resource#close() closed}
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* when this scope is {@linkplain #close() closed}.
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*
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* @param obj The reference counted object to add to this scope.
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* @param <T> The type of the reference counted object.
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* @return The same exact object that was added; further operations can be chained on the object after this method
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* call.
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*/
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public <T extends Resource<T>> T add(T obj) {
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deque.addLast(obj);
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return obj;
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}
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/**
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* Close this scope and all the reference counted object it contains.
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*/
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@Override
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public void close() {
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Resource<?> obj;
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while ((obj = deque.pollLast()) != null) {
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obj.close();
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}
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}
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}
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