org.dataloader.CacheMap Maven / Gradle / Ivy
/*
* Copyright (c) 2016 The original author or authors
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Apache License v2.0 which accompanies this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* The Apache License v2.0 is available at
* http://www.opensource.org/licenses/apache2.0.php
*
* You may elect to redistribute this code under either of these licenses.
*/
package org.dataloader;
import org.dataloader.impl.DefaultCacheMap;
import java.util.concurrent.CompletableFuture;
/**
* Cache map interface for data loaders that use caching.
*
* The default implementation used by the data loader is based on a {@link java.util.LinkedHashMap}. Note that the
* implementation could also have used a regular {@link java.util.Map} instead of this {@link CacheMap}, but
* this aligns better to the reference data loader implementation provided by Facebook
*
* Also it doesn't require you to implement the full set of map overloads, just the required methods.
*
* @param type parameter indicating the type of the cache keys
* @param type parameter indicating the type of the data that is cached
*
* @author Arnold Schrijver
* @author Brad Baker
*/
public interface CacheMap {
/**
* Creates a new cache map, using the default implementation that is based on a {@link java.util.LinkedHashMap}.
*
* @param type parameter indicating the type of the cache keys
* @param type parameter indicating the type of the data that is cached
*
* @return the cache map
*/
static CacheMap> simpleMap() {
return new DefaultCacheMap<>();
}
/**
* Checks whether the specified key is contained in the cach map.
*
* @param key the key to check
*
* @return {@code true} if the cache contains the key, {@code false} otherwise
*/
boolean containsKey(U key);
/**
* Gets the specified key from the cache map.
*
* May throw an exception if the key does not exists, depending on the cache map implementation that is used,
* so be sure to check {@link CacheMap#containsKey(Object)} first.
*
* @param key the key to retrieve
*
* @return the cached value, or {@code null} if not found (depends on cache implementation)
*/
V get(U key);
/**
* Creates a new cache map entry with the specified key and value, or updates the value if the key already exists.
*
* @param key the key to cache
* @param value the value to cache
*
* @return the cache map for fluent coding
*/
CacheMap set(U key, V value);
/**
* Deletes the entry with the specified key from the cache map, if it exists.
*
* @param key the key to delete
*
* @return the cache map for fluent coding
*/
CacheMap delete(U key);
/**
* Clears all entries of the cache map
*
* @return the cache map for fluent coding
*/
CacheMap clear();
}