/*
* Copyright (c) 2008-2017, Hazelcast, 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.hazelcast.client.config;
import com.hazelcast.topic.TopicOverloadPolicy;
import java.util.concurrent.Executor;
import static com.hazelcast.topic.TopicOverloadPolicy.BLOCK;
import static com.hazelcast.util.Preconditions.checkNotNull;
import static com.hazelcast.util.Preconditions.checkPositive;
/**
* Contains the ReliableTopic configuration for a client.
*
* @see com.hazelcast.client.proxy.ClientReliableTopicProxy
*/
public class ClientReliableTopicConfig {
/**
* The default read batch size.
*/
public static final int DEFAULT_READ_BATCH_SIZE = 10;
/**
* The default slow consumer policy.
*/
public static final TopicOverloadPolicy DEFAULT_TOPIC_OVERLOAD_POLICY = BLOCK;
private Executor executor;
private int readBatchSize = DEFAULT_READ_BATCH_SIZE;
private String name;
private TopicOverloadPolicy topicOverloadPolicy = DEFAULT_TOPIC_OVERLOAD_POLICY;
/**
* Creates a new ReliableTopicConfig with default settings.
*/
public ClientReliableTopicConfig(String name) {
this.name = checkNotNull(name, "name");
}
/**
* Gets the name of the reliable topic.
*
* @return the name of the reliable topic.
*/
public String getName() {
return name;
}
/**
* Gets the TopicOverloadPolicy for this reliable topic.
*
* @return the TopicOverloadPolicy.
*/
public TopicOverloadPolicy getTopicOverloadPolicy() {
return topicOverloadPolicy;
}
/**
* Sets the TopicOverloadPolicy for this reliable topic. Check the {@link TopicOverloadPolicy} for more details about
* this setting.
*
* @param topicOverloadPolicy the new TopicOverloadPolicy.
* @return the updated reliable topic config.
* @throws IllegalArgumentException if topicOverloadPolicy is null.
*/
public ClientReliableTopicConfig setTopicOverloadPolicy(TopicOverloadPolicy topicOverloadPolicy) {
this.topicOverloadPolicy = checkNotNull(topicOverloadPolicy, "topicOverloadPolicy can't be null");
return this;
}
/**
* Gets the Executor that is going to process the events.
*
* If no Executor is selected, then the {@link com.hazelcast.spi.ExecutionService#ASYNC_EXECUTOR} is used.
*
* @return the Executor used to process events.
* @see #setExecutor(Executor)
*/
public Executor getExecutor() {
return executor;
}
/**
* Sets the Executor that is going to process the event.
*
* In some cases it is desirable to set a specific Executor. For example, you may want to isolate a certain topic from other
* topics because it contains long running messages or very high priority messages.
*
* A single Executor can be shared between multiple Reliable topics, although it could take more time to process a message.
* If a single Executor is not shared with other reliable topics, then the Executor only needs to have a single thread.
*
* @param executor the Executor. if the executor is null, the {@link com.hazelcast.spi.ExecutionService#ASYNC_EXECUTOR} will
* be used to process the event.
* @return the updated config.
*/
public ClientReliableTopicConfig setExecutor(Executor executor) {
this.executor = executor;
return this;
}
/**
* Gets the maximum number of items to read in a batch. Returned value will always be equal or larger than 1.
*
* @return the read batch size.
*/
public int getReadBatchSize() {
return readBatchSize;
}
/**
* Sets the read batch size.
*
* The ReliableTopic tries to read a batch of messages from the ringbuffer. It will get at least one, but
* if there are more available, then it will try to get more to increase throughput. The minimal read
* batch size can be influenced using the read batch size.
*
* Apart from influencing the number of messages to download, the readBatchSize also determines how many
* messages will be processed by the thread running the MessageListener before it returns back to the pool
* to look for other MessageListeners that need to be processed. The problem with returning to the pool and
* looking for new work is that interacting with an Executor is quite expensive due to contention on the
* work-queue. The more work that can be done without retuning to the pool, the smaller the overhead.
*
* If the readBatchSize is 10 and there are 50 messages available, 10 items are retrieved and processed
* consecutively before the thread goes back to the pool and helps out with the processing of other messages.
*
* If the readBatchSize is 10 and there are 2 items available, 2 items are retrieved and processed consecutively.
*
* If the readBatchSize is an issue because a thread will be busy too long with processing a single MessageListener
* and it can't help out other MessageListeners, increase the size of the threadpool so the other MessageListeners don't
* need to wait for a thread, but can be processed in parallel.
*
* @param readBatchSize the maximum number of items to read in a batch.
* @return the updated reliable topic config.
* @throws IllegalArgumentException if readBatchSize is smaller than 1.
*/
public ClientReliableTopicConfig setReadBatchSize(int readBatchSize) {
this.readBatchSize = checkPositive(readBatchSize, "readBatchSize should be positive");
return this;
}
@Override
public String toString() {
return "ClientReliableTopicConfig{"
+ "name='" + name + '\''
+ ", topicOverloadPolicy=" + topicOverloadPolicy
+ ", executor=" + executor
+ ", readBatchSize=" + readBatchSize
+ '}';
}
}