/**
 *
 * Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
 *
 * 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 com.speedment.runtime.core.internal.util;

import com.speedment.runtime.core.util.ClassMapper;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Stream;

import static java.util.Objects.requireNonNull;

/**
 *
 * @author pemi
 * @param <V> the base type
 */
public abstract class DefaultClassMapper<V> implements ClassMapper<V> {

    protected final Consumer<V> NOTHING = v -> {};

    private final Map<Class<?>, V> map;

    public DefaultClassMapper() {
        this.map = new ConcurrentHashMap<>();
    }

    protected <T extends V> T put(T newItem, Function<V, Class<?>> keyMapper) {
        requireNonNull(newItem);
        requireNonNull(keyMapper);
        return put(newItem, NOTHING, NOTHING, keyMapper);
    }

    protected <T extends V> T put(T newItem, Consumer<V> added, Consumer<V> removed, Function<V, Class<?>> keyMapper) {
        requireNonNull(newItem);
        requireNonNull(added);
        requireNonNull(removed);
        requireNonNull(keyMapper);
        added.accept(newItem);

        @SuppressWarnings("unchecked") // Must be same type!
        final T oldItem = (T) map.put(keyMapper.apply(newItem), newItem);
        if (oldItem != null) {
            removed.accept(oldItem);
        }

        return oldItem;
    }

    @SuppressWarnings("unchecked") // Must be same type!
    @Override
    public <R extends V> R getOrThrow(Class<R> clazz) {
        requireNonNull(clazz);
        return (R) map.get(clazz);
    }

    @Override
    public Stream<Map.Entry<Class<?>, V>> stream() {
        return map.entrySet().stream();
    }

}