GenericStoreService.java
/*
* Copyright (c) 2023. Roland T. Lichti, Kaiserpfalz EDV-Service.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package de.kaiserpfalzedv.commons.core.store;
import java.util.HashMap;
import java.util.Optional;
import java.util.UUID;
import de.kaiserpfalzedv.commons.api.resources.Resource;
import de.kaiserpfalzedv.commons.api.store.OptimisticLockStoreException;
import de.kaiserpfalzedv.commons.api.store.StoreService;
import lombok.EqualsAndHashCode;
import lombok.ToString;
import lombok.extern.slf4j.Slf4j;
/**
* GenericStoreService -- an ephemeral store for Resources.
* <p>
* This is a memory alternative for a persistent data store.
*
* @param <T> The resource to be stored inside the data store.
* @author klenkes74 {@literal <rlichti@kaiserpfalz-edv.de>}
* @since 2.0.0 2021-05-24
*/
@ToString
@EqualsAndHashCode
@Slf4j
public abstract class GenericStoreService<T extends Resource<?>> implements StoreService<T> {
/**
* The name based memory store for guilds.
*/
private final HashMap<String, T> namedStore = new HashMap<>(10);
/**
* The uid based memory store for guilds.
*/
private final HashMap<UUID, T> uidStore = new HashMap<>(10);
@Override
public Optional<T> findByNameSpaceAndName(final String nameSpace, final String name) {
final String key = this.generateStoreKey(nameSpace, name);
return Optional.ofNullable(this.namedStore.get(key));
}
@Override
public Optional<T> findByUid(final UUID uid) {
return Optional.ofNullable(this.uidStore.get(uid));
}
private String generateStoreKey(final String nameSpace, final String name) {
return nameSpace + "-" + name;
}
@Override
public T save(final T object) throws OptimisticLockStoreException {
log.trace("Saving: {}", object);
final String key = this.generateStoreKey(object.getNameSpace(), object.getName());
@SuppressWarnings("unchecked")
final
T data = (!this.namedStore.containsKey(key))
? object
: (T) object.increaseGeneration();
this.checkOptimisticLocking(key, data);
this.namedStore.put(key, data);
this.uidStore.put(object.getUid(), data);
return data;
}
private void checkOptimisticLocking(final String key, final T object) {
if (
this.namedStore.containsKey(key)
&& (this.namedStore.get(key).getGeneration() >= object.getGeneration())
) {
throw new OptimisticLockStoreException(this.namedStore.get(key).getGeneration(), object.getGeneration());
}
}
@Override
public void remove(final T object) {
final String key = this.generateStoreKey(object.getNameSpace(), object.getName());
this.namedStore.remove(key);
this.uidStore.remove(object.getUid());
}
@Override
public void remove(final String nameSpace, final String name) {
final String key = this.generateStoreKey(nameSpace, name);
if (this.namedStore.containsKey(key)) {
this.uidStore.remove(this.namedStore.get(key).getUid());
this.namedStore.remove(key);
}
}
@Override
public void remove(final UUID uid) {
if (this.uidStore.containsKey(uid)) {
final T data = this.uidStore.get(uid);
final String key = this.generateStoreKey(data.getNameSpace(), data.getName());
this.namedStore.remove(key);
this.uidStore.remove(uid);
}
}
}