org.cache2k.configuration.CustomizationSupplier Maven / Gradle / Ivy
package org.cache2k.configuration;
/*
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* cache2k API
* %%
* Copyright (C) 2000 - 2020 headissue GmbH, Munich
* %%
* 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,
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* See the License for the specific language governing permissions and
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*/
import org.cache2k.CacheManager;
import java.io.Serializable;
/**
* Supplies a cache customizations like {@code ExpiryPolicy} or {@code CacheLoader}.
* An implementation must implement proper a {@code hashCode} and {@code equals} method.
*
* Implementations of this class that should be usable within the XML configuration
* need to implement {@link Serializable}. This is not done so in this interface since
* there may be suppliers which are used within the program that are intentionally not
* serializable, such as {@link CustomizationReferenceSupplier}.
*
* @author Jens Wilke
*/
public interface CustomizationSupplier {
/**
* Create or return an existing customization instance.
*
* Developer note: The interface lacks context where the customization is used,
* e.g. the cache name. With the cache name, different customizations could share
* data or expose themselves
*
* @param manager The manager can be used to retrieve the class loader or
* additional properties needed to configure the customization.
* @throws Exception the method may throw arbitrary exceptions. The exception
* is wrapped into a {@link org.cache2k.CacheException} and
* rethrown. When the creation of a customization fails, the
* cache will not be usable.
* @return created customization, never {@code null}
*/
T supply(CacheManager manager) throws Exception;
}