41 lines
1.5 KiB
Java
41 lines
1.5 KiB
Java
// Copyright (C) 2016 The Android Open Source Project
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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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package com.google.gerrit.server.git;
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import java.io.IOException;
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import java.util.Optional;
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import org.eclipse.jgit.lib.ObjectId;
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/**
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* Simple short-lived cache of individual refs read from a repo.
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*
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* <p>Within a single request that is known to read a small bounded number of refs, this class can
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* be used to ensure a consistent view of one ref, and avoid multiple system calls to read refs
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* multiple times.
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*
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* <p><strong>Note:</strong> Implementations of this class are only appropriate for short-term
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* caching, and do not support invalidation. It is also not threadsafe.
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*/
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public interface RefCache {
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/**
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* Get the possibly-cached value of a ref.
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*
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* @param refName name of the ref.
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* @return value of the ref; absent if the ref does not exist in the repo. Never null, and never
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* present with a value of {@link ObjectId#zeroId()}.
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*/
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Optional<ObjectId> get(String refName) throws IOException;
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}
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