com.fluxtion.agrona.concurrent.CompositeAgent Maven / Gradle / Ivy
/*
* Copyright 2014-2024 Real Logic Limited.
*
* 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 com.fluxtion.agrona.concurrent;
import java.util.List;
import java.util.Objects;
/**
* Group several {@link Agent}s into one composite, so they can be scheduled as a unit.
*/
public class CompositeAgent implements Agent
{
private final Agent[] agents;
private final String roleName;
private int agentIndex = 0;
/**
* @param agents the parts of this composite, at least one agent and no null agents allowed
* @throws IllegalArgumentException if an empty array of agents is provided
* @throws NullPointerException if the array or any element is null
*/
public CompositeAgent(final List agents)
{
this(agents.toArray(new Agent[0]));
}
/**
* @param agents the parts of this composite, at least one agent and no null agents allowed
* @throws IllegalArgumentException if an empty array of agents is provided, or single agent provided
* @throws NullPointerException if the array or any element is null
*/
public CompositeAgent(final Agent... agents)
{
if (agents.length == 0)
{
throw new IllegalArgumentException("requires at least one sub-agent");
}
this.agents = new Agent[agents.length];
final StringBuilder sb = new StringBuilder(agents.length * 16);
sb.append('[');
int i = 0;
for (final Agent agent : agents)
{
Objects.requireNonNull(agent, "agent cannot be null");
sb.append(agent.roleName()).append(',');
this.agents[i++] = agent;
}
sb.setCharAt(sb.length() - 1, ']');
roleName = sb.toString();
}
/**
* {@inheritDoc}
*/
public String roleName()
{
return roleName;
}
/**
* {@inheritDoc}
*
* Note that one agent throwing an exception on start will not prevent other agents from being started.
*
* @throws RuntimeException if any sub-agent throws an exception onStart. The agents exceptions are collected as
* suppressed exceptions in the thrown exception.
*/
public void onStart()
{
RuntimeException ce = null;
for (final Agent agent : agents)
{
try
{
agent.onStart();
}
catch (final Exception ex)
{
if (ce == null)
{
ce = new RuntimeException(getClass().getName() + ": underlying agent error on start");
}
ce.addSuppressed(ex);
}
}
if (null != ce)
{
throw ce;
}
}
/**
* {@inheritDoc}
*/
public int doWork() throws Exception
{
int workCount = 0;
final Agent[] agents = this.agents;
while (agentIndex < agents.length)
{
final Agent agent = agents[agentIndex++];
workCount += agent.doWork();
}
agentIndex = 0;
return workCount;
}
/**
* {@inheritDoc}
*
* Note that one agent throwing an exception on close will not prevent other agents from being closed.
*
* @throws RuntimeException if any sub-agent throws an exception onClose. The agents exceptions are collected as
* suppressed exceptions in the thrown exception.
*/
public void onClose()
{
RuntimeException ce = null;
for (final Agent agent : agents)
{
try
{
agent.onClose();
}
catch (final Exception ex)
{
if (ce == null)
{
ce = new RuntimeException(getClass().getName() + ": underlying agent error on close");
}
ce.addSuppressed(ex);
}
}
if (null != ce)
{
throw ce;
}
}
}