/*
 * 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.jdbi.v3.core.config;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;

import org.jdbi.v3.meta.Beta;

Hold metadata caches which maps various JVM constants into pre-parsed forms.
For example, bean property accessors, or normalized enum constants.
Note that unlike most JdbiConfig types, this cache is Jdbi level and shared,
so it should not hold data that needs to respect reconfiguration.
Additionally, currently there is no expiration policy, as nearly all keys are
references to JVM constant pool entries.
This makes it unsuitable as a general-purpose shared cache.
/**
 * Hold metadata caches which maps various JVM constants into pre-parsed forms.
 * For example, bean property accessors, or normalized enum constants.
 * Note that unlike most JdbiConfig types, this cache is Jdbi level and shared,
 * so it should not hold data that needs to respect reconfiguration.
 * Additionally, currently there is no expiration policy, as nearly all keys are
 * references to JVM constant pool entries.
 * <b>This makes it unsuitable as a general-purpose shared cache.</b>
 */
@Beta
public final class JdbiCaches implements JdbiConfig<JdbiCaches> {
    private final Map<JdbiCache<?, ?>, Map<Object, Object>> caches = new ConcurrentHashMap<>();

    
Does not actually create a copy!!
/**
     * Does not actually create a copy!!
     */
    @Override
    public JdbiCaches createCopy() {
        return this;
    }

    public static <K, V> JdbiCache<K, V> declare(Function<K, V> computer) {
        return declare(Function.identity(), computer);
    }

    public static <K, V> JdbiCache<K, V> declare(Function<K, ?> keyNormalizer, Function<K, V> computer) {
        return new JdbiCache<K, V>() {
            @SuppressWarnings("unchecked")
            @Override
            public V get(K key, ConfigRegistry config) {
                return (V) config.get(JdbiCaches.class).caches
                        .computeIfAbsent(this, x -> new ConcurrentHashMap<>())
                        .computeIfAbsent(keyNormalizer.apply(key), x -> computer.apply(key));
            }
        };
    }
}