sx.blah.discord.util.cache.Cache Maven / Gradle / Ivy
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/*
* This file is part of Discord4J.
*
* Discord4J is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Discord4J 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Discord4J. If not, see The type of object stored by the cache.
*/
public final class Cache implements Iterable {
/**
* The default cache delegate provider used by Discord4J.
*/
public static final ICacheDelegateProvider DEFAULT_PROVIDER = new DefaultCacheDelegateProvider();
/**
* A cache delegate provider which stores nothing.
*/
public static final ICacheDelegateProvider IGNORING_PROVIDER = new IgnoringCacheDelegateProvider();
/**
* The cache's underlying delegate.
*/
private volatile ICacheDelegate delegate;
public Cache(ICacheDelegate delegate) {
this.delegate = delegate;
}
public Cache(DiscordClientImpl client, Class self) {
this(client.getCacheProvider().provide(self));
}
/**
* Sets the cache's delegate.
*
* NOTE: No data is copied from the old delegate to the new one.
*
* @param delegate The new delegate.
*/
public void setDelegate(ICacheDelegate delegate) {
this.delegate = delegate;
}
/**
* Gets the cache's delegate.
*
* @return The cache delegate.
*/
public ICacheDelegate getDelegate() {
return delegate;
}
/**
* Gets the number of elements stored in the cache.
*
* @return The number of elements stored in the cache.
*/
public int size() {
return delegate.size();
}
/**
* Gets whether the cache is empty.
*
* @return Whether the cache is empty.
*/
public boolean isEmpty() {
return size() < 1;
}
/**
* Gets whether the given key is present in the cache.
*
* @param key The key to search for.
* @return Whether the given key is present in the cache.
*/
public boolean containsKey(Object key) {
if (key instanceof String) {
return delegate.contains((String) key);
} else if (key instanceof Long) {
return delegate.contains((Long) key);
} else {
return false;
}
}
/**
* Gets whether the given key is present in the cache.
*
* @param key The key to search for.
* @return Whether the given key is present in the cache.
*/
public boolean containsKey(long key) {
return delegate.contains(key);
}
/**
* Gets whether the given value is present in the cache.
*
* @param value The value to search for.
* @return Whether the given value is present in the cache.
*/
public boolean containsValue(Object value) {
return value instanceof IIDLinkedObject && delegate.contains((T) value);
}
/**
* Gets an object by its unique snowflake ID.
*
* @param key The ID of the desired object.
* @return The object with the provided ID (or null if one was not found).
*/
public T get(Object key) {
if (key instanceof String) {
return delegate.retrieve((String) key).orElse(null);
} else if (key instanceof Long) {
return delegate.retrieve((Long) key).orElse(null);
} else {
return null;
}
}
/**
* Gets an object by its unique snowflake ID.
*
* @param key The ID of the desired object.
* @return The object with the provided ID (or null if one was not found).
*/
public T get(long key) {
return delegate.retrieve(key).orElse(null);
}
/**
* Gets an object by its unique snowflake ID. If no object is found, the supplier must supply the object instead.
*
* @param key The ID of the desired object.
* @param supplier The supplier to invoke if no object is found.
* @return The object with provided ID (or the result of the supplier).
*/
public T getOrElseGet(Object key, Supplier supplier) {
T val = get(key);
return val == null ? supplier.get() : val;
}
/**
* Gets an object by its unique snowflake ID. If no object is found, the supplier must supply the object instead.
*
* @param key The ID of the desired object.
* @param supplier The supplier to invoke if no object is found.
* @return The object with provided ID (or the result of the supplier).
*/
public T getOrElseGet(long key, Supplier supplier) {
T val = get(key);
return val == null ? supplier.get() : val;
}
/**
* Puts an object into the cache.
*
* @param value The object to put.
* @return The previous object that had the same ID or null if there was not one.
*/
public T put(T value) {
return delegate.put(value).orElse(null);
}
/**
* Puts an object into the cache if there is not already a value associated with the given key.
*
* @param id The ID to associate with the value.
* @param valueSupplier The supplier to invoke if the key is absent.
* @return Null.
*/
public T putIfAbsent(String id, Supplier valueSupplier) {
if (containsKey(id))
return null;
else
return put(valueSupplier.get());
}
/**
* Puts an object into the cache if there is not already a value associated with the given key.
*
* @param id The ID to associate with the value.
* @param valueSupplier The supplier to invoke if the key is absent.
* @return Null.
*/
public T putIfAbsent(long id, Supplier valueSupplier) {
if (containsKey(id))
return null;
else
return put(valueSupplier.get());
}
/**
* Removes an object from the cache.
*
* @param obj The ID of the object to remove or the object itself.
* @return The object that was removed.
*/
public T remove(Object obj) {
if (obj instanceof String) {
return delegate.remove((String) obj).orElse(null);
} else if (obj instanceof Long) {
return delegate.remove((Long) obj).orElse(null);
} else if (obj instanceof IIDLinkedObject) {
return delegate.remove((T) obj).orElse(null);
} else {
return null;
}
}
/**
* Removes an object from the cache.
*
* @param key The ID of the object to remove.
* @return The object that was removed.
*/
public T remove(long key) {
return delegate.remove(key).orElse(null);
}
/**
* Puts every element of the given cache into the cache.
*
* @param objs The objects to insert.
* @return Any objects that were replaced by the operation.
*/
public Collection putAll(Cache objs) {
return putAll(objs.values());
}
/**
* Puts every element of the given collection into the cache.
*
* @param objs The objects to insert.
* @return Any objects that were replaced by the operation.
*/
public Collection putAll(Collection objs) {
return delegate.putAll(objs);
}
/**
* Clears the cache.
*/
public void clear() {
delegate.clear();
}
/**
* Gets the IDs of every object in the cache.
*
* @return The IDs of every object in the cache.
*/
public Collection ids() {
return delegate.ids();
}
/**
* Gets the IDs of every object in the cache.
*
* @return The IDs of every object in the cache.
*/
public Collection longIDs() {
return delegate.longIDs();
}
/**
* Gets every value in the cache.
*
* @return Every value in the cache.
*/
public Collection values() {
return delegate.values();
}
/**
* See {@link Collection#stream()}.
*/
public Stream stream() {
return delegate.stream();
}
/**
* See {@link Collection#parallelStream()}.
*/
public Stream parallelStream() {
return delegate.parallelStream();
}
/**
* Gets a copy of the cache.
*
* @return A copy of the cache.
*/
public Cache copy() {
return new Cache<>(delegate.copy());
}
/**
* Gets a copy of the cache as a long map.
*
* @return A copy of the cache as a long map.
*/
public LongMap mapCopy() {
return delegate.mapCopy();
}
/**
* Performs the given action for each pair of key and value in the cache.
*
* @param action The action to perform for each pair of key and value in the cache.
*/
public void forEach(LongObjConsumer action) {
delegate.forEach(action);
}
/**
* Performs the given action for each pair of key and value in the cache while the function returns true.
*
* @param predicate The action to perform for each pair of key and value in the cache.
* @return Whether iterating was interrupted (whether the predicate ever returned false).
*/
public boolean forEachWhile(LongObjPredicate predicate) {
return delegate.forEachWhile(predicate);
}
/**
* Gets the first non-null value produced by the given function which is applied to every pair of keys and values
* in the cache.
*
* @param function The function to apply to each pair.
* @return The first non-null value produced by the given function
*/
public Z findResult(LongObjFunction function) {
return delegate.findResult(function);
}
/**
* {@inheritDoc}
*/
@Override
public Iterator iterator() {
return delegate.iterator();
}
/**
* A cache delegate which is backed by a map.
*/
public static class MapCacheDelegate implements ICacheDelegate {
/**
* The backing map.
*/
private final LongMap backing;
/**
* The lock used for read and write operations.
*/
private final ReadWriteLock lock = new ReentrantReadWriteLock();
public MapCacheDelegate() {
this(LongMap.newMap());
}
public MapCacheDelegate(LongMap backing) {
this.backing = backing;
}
@Override
public Optional retrieve(long id) {
lock.readLock().lock();
try {
return Optional.ofNullable(backing.get(id));
} finally {
lock.readLock().unlock();
}
}
@Override
public Optional put(T obj) {
lock.writeLock().lock();
try {
return Optional.ofNullable(backing.put(obj.getLongID(), obj));
} finally {
lock.writeLock().unlock();
}
}
@Override
public Optional remove(long id) {
lock.writeLock().lock();
try {
return Optional.ofNullable(backing.remove(id));
} finally {
lock.writeLock().unlock();
}
}
@Override
public Collection clear() {
lock.writeLock().lock();
try {
Collection cleared = values();
backing.clear();
return cleared;
} finally {
lock.writeLock().unlock();
}
}
@Override
public boolean contains(long id) {
lock.readLock().lock();
try {
return backing.containsKey(id);
} finally {
lock.readLock().unlock();
}
}
@Override
public int size() {
lock.readLock().lock();
try {
return backing.size();
} finally {
lock.readLock().unlock();
}
}
@Override
public Iterator iterator() {
lock.readLock().lock();
try {
return backing.values().iterator();
} finally {
lock.readLock().unlock();
}
}
@Override
public LongSet longIDs() {
lock.readLock().lock();
try {
return backing.keySet();
} finally {
lock.readLock().unlock();
}
}
@Override
public Collection values() {
lock.readLock().lock();
try {
return backing.values();
} finally {
lock.readLock().unlock();
}
}
@Override
public ICacheDelegate copy() {
return new MapCacheDelegate<>(mapCopy());
}
@Override
public LongMap mapCopy() {
lock.readLock().lock();
try {
return LongMap.copyMap(backing);
} finally {
lock.readLock().unlock();
}
}
@Override
public void forEach(LongObjConsumer action) {
lock.readLock().lock();
try {
backing.forEach(action);
} finally {
lock.readLock().unlock();
}
}
@Override
public boolean forEachWhile(LongObjPredicate predicate) {
lock.readLock().lock();
try {
return backing.forEachWhile(predicate);
} finally {
lock.readLock().unlock();
}
}
@Override
public Z findResult(LongObjFunction function) {
AtomicReference result = new AtomicReference<>();
forEachWhile((key, value) -> {
Z tmp = function.apply(key, value);
if (tmp != null) {
result.set(tmp);
return false;
}
return true;
});
return result.get();
}
}
/**
* A cache delegate which stores nothing.
*/
public static class IgnoringCacheDelegate implements ICacheDelegate {
/**
* Returns an empty optional.
*
* @return An empty optional.
*/
@Override
public Optional retrieve(long id) {
return Optional.empty();
}
/**
* Returns an empty optional.
*
* @return An empty optional.
*/
@Override
public Optional put(T obj) {
return Optional.empty();
}
/**
* Returns an empty optional.
*
* @return An empty optional.
*/
@Override
public Optional remove(long id) {
return Optional.empty();
}
/**
* Returns an empty set.
*
* @return An empty set.
*/
@Override
public Collection clear() {
return Collections.emptySet();
}
/**
* Returns 0.
*
* @return 0.
*/
@Override
public int size() {
return 0;
}
/**
* Returns an empty iterator.
*
* @return An empty iterator.
*/
@Override
public Iterator iterator() {
return Collections.emptyIterator();
}
/**
* Returns an empty long set.
*
* @return An empty long set.
*/
@Override
public LongSet longIDs() {
return LongMap.EmptyLongSet.INSTANCE;
}
/**
* Returns an empty set.
*
* @return An empty set.
*/
@Override
public Collection values() {
return Collections.emptySet();
}
/**
* Returns the same cache delegate instance.
*
* @return The same cache delegate instance.
*/
@Override
public ICacheDelegate copy() {
return this;
}
/**
* Returns an empty long map.
*
* @return An empty long map.
*/
@Override
public LongMap mapCopy() {
return LongMap.emptyMap();
}
/**
* No-op. Does nothing.
*/
@Override
public void forEach(LongObjConsumer action) {}
/**
* No-op. Does nothing.
*
* @return True.
*/
@Override
public boolean forEachWhile(LongObjPredicate predicate) {
return true;
}
/**
* No-op. Does nothing.
*
* @return Null.
*/
@Override
public Z findResult(LongObjFunction function) {
return null;
}
}
}
/**
* The default cache delegate provider used by Discord4J. Always provides a {@link Cache.MapCacheDelegate}.
*/
class DefaultCacheDelegateProvider implements ICacheDelegateProvider {
@Override
public ICacheDelegate provide(Class clazz) {
return new Cache.MapCacheDelegate<>();
}
}
/**
* A cache delegate provider which always provides {@link Cache.IgnoringCacheDelegate}.
*/
class IgnoringCacheDelegateProvider implements ICacheDelegateProvider {
@Override
public ICacheDelegate provide(Class clazz) {
return new Cache.IgnoringCacheDelegate<>();
}
}