/*
 * 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.dubbo.registry.client;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.ConcurrentHashMapUtils;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.apache.dubbo.rpc.model.ScopeModelAware;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Abstract {@link ServiceDiscoveryFactory} implementation with cache, the subclass
 * should implement {@link #createDiscovery(URL)} method to create an instance of {@link ServiceDiscovery}
 *
 * @see ServiceDiscoveryFactory
 * @since 2.7.5
 */
public abstract class AbstractServiceDiscoveryFactory implements ServiceDiscoveryFactory, ScopeModelAware {

    protected ApplicationModel applicationModel;
    private final ConcurrentMap<String, ServiceDiscovery> discoveries = new ConcurrentHashMap<>();

    @Override
    public void setApplicationModel(ApplicationModel applicationModel) {
        this.applicationModel = applicationModel;
    }

    public List<ServiceDiscovery> getAllServiceDiscoveries() {
        return Collections.unmodifiableList(new LinkedList<>(discoveries.values()));
    }

    @Override
    public ServiceDiscovery getServiceDiscovery(URL registryURL) {
        String key = registryURL.toServiceStringWithoutResolving();
        return ConcurrentHashMapUtils.computeIfAbsent(discoveries, key, k -> createDiscovery(registryURL));
    }

    protected abstract ServiceDiscovery createDiscovery(URL registryURL);
}
