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package org.glassfish.grizzly.strategies;
import java.io.IOException;
import java.util.concurrent.Executor;
import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.IOEvent;
import org.glassfish.grizzly.IOStrategy;
import org.glassfish.grizzly.Transport;
import org.glassfish.grizzly.nio.NIOConnection;
import org.glassfish.grizzly.nio.NIOTransport;
import org.glassfish.grizzly.threadpool.ThreadPoolConfig;
/**
* Simple dynamic strategy, which switches I/O processing strategies, basing
* on statistics. This implementation takes in consideration number of
* {@link java.nio.channels.SelectionKey}s, which were selected last time by
* {@link java.nio.channels.Selector}.
*
* <tt>SimpleDynamicIOStrategy</tt> is able to use 2 strategies underneath:
* {@link SameThreadIOStrategy}, {@link WorkerThreadIOStrategy}.
* And is able to switch between them basing on corresponding threshold
* (threshold represents the number of selected
* {@link java.nio.channels.SelectionKey}s).
*
* So the strategy is getting applied following way:
*
* {@link SameThreadIOStrategy} --(worker-thread threshold)--> {@link WorkerThreadIOStrategy}.
*
* @author Alexey Stashok
*/
public final class SimpleDynamicNIOStrategy implements IOStrategy {
private static final SimpleDynamicNIOStrategy INSTANCE = new SimpleDynamicNIOStrategy();
private final SameThreadIOStrategy sameThreadStrategy;
private final WorkerThreadIOStrategy workerThreadStrategy;
private static final int WORKER_THREAD_THRESHOLD = 1;
// ------------------------------------------------------------ Constructors
private SimpleDynamicNIOStrategy() {
sameThreadStrategy = SameThreadIOStrategy.getInstance();
workerThreadStrategy = WorkerThreadIOStrategy.getInstance();
}
// ---------------------------------------------------------- Public Methods
public static SimpleDynamicNIOStrategy getInstance() {
return INSTANCE;
}
@Override
public boolean executeIoEvent(Connection connection, IOEvent ioEvent) throws IOException {
return executeIoEvent(connection, ioEvent, true);
}
// ------------------------------------------------- Methods from IOStrategy
@Override
public Executor getThreadPoolFor(final Connection connection,
final IOEvent ioEvent) {
final int lastSelectedKeysCount = getLastSelectedKeysCount(connection);
return lastSelectedKeysCount <= WORKER_THREAD_THRESHOLD ?
sameThreadStrategy.getThreadPoolFor(connection, ioEvent) :
workerThreadStrategy.getThreadPoolFor(connection, ioEvent);
}
@Override
public boolean executeIoEvent(final Connection connection,
final IOEvent ioEvent, final boolean isIoEventEnabled)
throws IOException {
final int lastSelectedKeysCount = getLastSelectedKeysCount(connection);
return ((lastSelectedKeysCount <= WORKER_THREAD_THRESHOLD)
? sameThreadStrategy.executeIoEvent(connection, ioEvent, isIoEventEnabled)
: workerThreadStrategy.executeIoEvent(connection, ioEvent, isIoEventEnabled));
}
@Override
public ThreadPoolConfig createDefaultWorkerPoolConfig(final Transport transport) {
final ThreadPoolConfig config = ThreadPoolConfig.defaultConfig().copy();
final int selectorRunnerCount = ((NIOTransport) transport).getSelectorRunnersCount();
config.setCorePoolSize(selectorRunnerCount * 2);
config.setMaxPoolSize(selectorRunnerCount * 2);
config.setMemoryManager(transport.getMemoryManager());
return config;
}
// --------------------------------------------------------- Private Methods
private static int getLastSelectedKeysCount(final Connection c) {
return ((NIOConnection) c).getSelectorRunner().getLastSelectedKeysCount();
}
}