46 lines
1.5 KiB
Java
46 lines
1.5 KiB
Java
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/*
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* Copyright (C) 2007 The Guava 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 com.google.common.collect;
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import com.google.common.annotations.Beta;
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/**
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* Provides equivalent behavior to {@link String#intern} for other immutable
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* types.
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*
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* @author Kevin Bourrillion
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* @since 3.0
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*/
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@Beta
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public interface Interner<E> {
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/**
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* Chooses and returns the representative instance for any of a collection of
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* instances that are equal to each other. If two {@linkplain Object#equals
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* equal} inputs are given to this method, both calls will return the same
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* instance. That is, {@code intern(a).equals(a)} always holds, and {@code
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* intern(a) == intern(b)} if and only if {@code a.equals(b)}. Note that
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* {@code intern(a)} is permitted to return one instance now and a different
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* instance later if the original interned instance was garbage-collected.
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*
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* <p>
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* <b>Warning:</b> do not use with mutable objects.
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*
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* @throws NullPointerException if {@code sample} is null
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*/
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E intern(E sample);
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}
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