AddressResolverGroup.java — netty Source File

Source Code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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 io.netty.resolver;

import io.netty.util.concurrent.EventExecutor;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.FutureListener;
import io.netty.util.concurrent.GenericFutureListener;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.io.Closeable;
import java.net.SocketAddress;
import java.util.IdentityHashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * Creates and manages {@link NameResolver}s so that each {@link EventExecutor} has its own resolver instance.
 */
public abstract class AddressResolverGroup<T extends SocketAddress> implements Closeable {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(AddressResolverGroup.class);

    /**
     * Note that we do not use a {@link ConcurrentMap} here because it is usually expensive to instantiate a resolver.
     */
    private final Map<EventExecutor, AddressResolver<T>> resolvers =
            new IdentityHashMap<EventExecutor, AddressResolver<T>>();

    private final Map<EventExecutor, GenericFutureListener<Future<Object>>> executorTerminationListeners =
            new IdentityHashMap<EventExecutor, GenericFutureListener<Future<Object>>>();

    protected AddressResolverGroup() { }

    /**
     * Returns the {@link AddressResolver} associated with the specified {@link EventExecutor}. If there's no associated
     * resolver found, this method creates and returns a new resolver instance created by
     * {@link #newResolver(EventExecutor)} so that the new resolver is reused on another
     * {@code #getResolver(EventExecutor)} call with the same {@link EventExecutor}.
     */
    public AddressResolver<T> getResolver(final EventExecutor executor) {
        ObjectUtil.checkNotNull(executor, "executor");

        if (executor.isShuttingDown()) {
// ... (69 more lines)