/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you 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.apache.logging.log4j.plugins.di.spi;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;
import org.apache.logging.log4j.plugins.di.Key;
import org.apache.logging.log4j.util.Cast;
import org.apache.logging.log4j.util.Lazy;

class SingletonScope implements Scope {
    private final Map<Key<?>, Supplier<?>> singletonProviders = new ConcurrentHashMap<>();

    @Override
    public <T> Supplier<T> get(final Key<T> key, final Supplier<T> unscoped) {
        return Cast.cast(singletonProviders.computeIfAbsent(key, ignored -> Lazy.lazy(unscoped)));
    }

    @Override
    public String toString() {
        return "[SingletonScope; size=" + singletonProviders.size() + "]";
    }
}
