org.springframework.integration.channel.DirectChannel.java Source code

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Here is the source code for org.springframework.integration.channel.DirectChannel.java

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/*
 * Copyright 2002-2019 the original author or authors.
 *
 * 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
 *
 *      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 org.springframework.integration.channel;

import org.springframework.integration.context.IntegrationProperties;
import org.springframework.integration.dispatcher.LoadBalancingStrategy;
import org.springframework.integration.dispatcher.RoundRobinLoadBalancingStrategy;
import org.springframework.integration.dispatcher.UnicastingDispatcher;

/**
 * A channel that invokes a single subscriber for each sent Message.
 * The invocation will occur in the sender's thread.
 *
 * @author Dave Syer
 * @author Mark Fisher
 * @author Iwein Fuld
 * @author Oleg Zhurakousky
 * @author Gary Russell
 */
public class DirectChannel extends AbstractSubscribableChannel {

    private final UnicastingDispatcher dispatcher = new UnicastingDispatcher();

    private volatile Integer maxSubscribers;

    /**
     * Create a channel with default {@link RoundRobinLoadBalancingStrategy}
     */
    public DirectChannel() {
        this(new RoundRobinLoadBalancingStrategy());
    }

    /**
     * Create a DirectChannel with a {@link LoadBalancingStrategy}. The
     * strategy <em>must not</em> be null.
     *
     * @param loadBalancingStrategy The load balancing strategy implementation.
     */
    public DirectChannel(LoadBalancingStrategy loadBalancingStrategy) {
        this.dispatcher.setLoadBalancingStrategy(loadBalancingStrategy);
    }

    /**
     * Specify whether the channel's dispatcher should have failover enabled.
     * By default, it will. Set this value to 'false' to disable it.
     *
     * @param failover The failover boolean.
     */
    public void setFailover(boolean failover) {
        this.dispatcher.setFailover(failover);
    }

    /**
     * Specify the maximum number of subscribers supported by the
     * channel's dispatcher.
     *
     * @param maxSubscribers The maximum number of subscribers allowed.
     */
    public void setMaxSubscribers(int maxSubscribers) {
        this.maxSubscribers = maxSubscribers;
        this.dispatcher.setMaxSubscribers(maxSubscribers);
    }

    @Override
    protected UnicastingDispatcher getDispatcher() {
        return this.dispatcher;
    }

    @Override
    protected void onInit() {
        super.onInit();
        if (this.maxSubscribers == null) {
            Integer max = this.getIntegrationProperty(IntegrationProperties.CHANNELS_MAX_UNICAST_SUBSCRIBERS,
                    Integer.class);
            this.setMaxSubscribers(max);
        }
    }

}