org.conqat.lib.commons.cache4j.backend.ECachingStrategy Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of teamscale-lib-commons Show documentation

Provides common utility functions

There is a newer version: 2024.7.2

Show newest version

/*
 * Copyright (c) CQSE GmbH
 *
 * 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.conqat.lib.commons.cache4j.backend;

import java.lang.ref.SoftReference;

/**
 * Enumeration of supported caching strategies.
 */
public enum ECachingStrategy {

	/** Performs no caching at all. */
	OFF,

	/**
	 * Caches exactly one element (basically the same as an LRU cache with size 1.
	 */
	SINGLE,

	/**
	 * Last recently used caching strategy. The parameter denotes the maximal number of elements stored.
	 */
	LRU,

	/**
	 * Memory sensitive caching using {@link SoftReference}s. This allows the cache to keep elements as
	 * long as memory is available, but free memory when requested by the garbage collector.
	 */
	MEMORY,

	/**
	 * Unlimited caching, i.e. the cache never discard data. This can lead to situations where the
	 * memory is exceeded.
	 */
	UNLIMITED;

	/**
	 * Returns the cache backend for the strategy (factory method).
	 * 
	 * @param parameter
	 *            the parameter used for the caching strategy. This is ignored by those strategies that
	 *            are not parameterizable.
	 */
	public  ICacheBackend getBackend(int parameter) {
		switch (this) {
		case OFF:
			return new NoneCacheBackend<>();
		case SINGLE:
			return new SingleElementCacheBackend<>();
		case LRU:
			if (parameter < 1) {
				parameter = 10;
			}
			return new LRUCacheBackend<>(parameter);
		case MEMORY:
			return new SoftRefCacheBackend<>();
		case UNLIMITED:
			return new UnlimitedCacheBackend<>();
		default:
			throw new AssertionError("Unknown enum value: " + this);
		}
	}
}