/*
 * 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.onlab.onos.store.trivial.impl;

import com.google.common.collect.ImmutableSet;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import org.onlab.onos.core.ApplicationId;
import org.onlab.onos.core.ApplicationIdStore;
import org.onlab.onos.core.DefaultApplicationId;

import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Simple implementation of the application ID registry using in-memory
 * structures.
 */
@Component(immediate = true)
@Service
public class SimpleApplicationIdStore implements ApplicationIdStore {

    private static final AtomicInteger ID_DISPENSER = new AtomicInteger(1);

    private final Map<Short, DefaultApplicationId> appIds = new ConcurrentHashMap<>();
    private final Map<String, DefaultApplicationId> appIdsByName = new ConcurrentHashMap<>();

    @Override
    public Set<ApplicationId> getAppIds() {
        return ImmutableSet.<ApplicationId>copyOf(appIds.values());
    }

    @Override
    public ApplicationId getAppId(Short id) {
        return appIds.get(id);
    }

    @Override
    public ApplicationId registerApplication(String name) {
        DefaultApplicationId appId = appIdsByName.get(name);
        if (appId == null) {
            short id = (short) ID_DISPENSER.getAndIncrement();
            appId = new DefaultApplicationId(id, name);
            appIds.put(id, appId);
            appIdsByName.put(name, appId);
        }
        return appId;
    }

}