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package org.glassfish.grizzly.samples.lifecycle;

import java.io.IOException;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.filterchain.FilterAdapter;
import org.glassfish.grizzly.filterchain.FilterChainContext;
import org.glassfish.grizzly.filterchain.NextAction;

/**
 * Sample {@link Filter}, which tracks the connections lifecycle
 * The new connections could be either accepted if we have server, or connected,
 * if we establish client connection.
 *
 * @author Alexey Stashok
 */
public class LifeCycleFilter extends FilterAdapter {
    private AtomicInteger totalConnectionNumber;
    private Map<Connection, Integer> activeConnectionsMap;

    public LifeCycleFilter() {
        totalConnectionNumber = new AtomicInteger();
        activeConnectionsMap = new ConcurrentHashMap<Connection, Integer>();
    }

    /**
     * Method is called, when new {@link Connection} was 
     * accepted by a {@link Transport}
     *
     * @param ctx the filter chain context
     * @param nextAction next action to be executed
     *                   by the chain (could be modified)
     * @return the next action to be executed by chain
     * @throws java.io.IOException
     */
    @Override
    public NextAction handleAccept(FilterChainContext ctx, NextAction nextAction) throws IOException {
        newConnection(ctx.getConnection());

        return nextAction;
    }


    /**
     * Method is called, when new client {@link Connection} was
     * connected to some endpoint
     *
     * @param ctx the filter chain context
     * @param nextAction next action to be executed
     *                   by the chain (could be modified)
     * @return the next action to be executed by chain
     * @throws java.io.IOException
     */
    @Override
    public NextAction handleConnect(FilterChainContext ctx, NextAction nextAction) throws IOException {
        newConnection(ctx.getConnection());

        return nextAction;
    }

    /**
     * Method is called, when the {@link Connection} is getting closed
     *
     * @param ctx the filter chain context
     * @param nextAction next action to be executed
     *                   by the chain (could be modified)
     * @return the next action to be executed by chain
     * @throws java.io.IOException
     */
    @Override
    public NextAction handleClose(FilterChainContext ctx, NextAction nextAction) throws IOException {
        activeConnectionsMap.remove(ctx.getConnection());
        return super.handleClose(ctx, nextAction);
    }

    /**
     * Add connection to the {@link Map>
     * 
     * @param connection new {@link Connection}
     */
    private void newConnection(Connection connection) {
        activeConnectionsMap.put(connection,
                totalConnectionNumber.incrementAndGet());
    }

    /**
     * Returns the total number of connections ever
     * created by the {@link Transport}
     * 
     * @return the total number of connections ever
     * created by the {@link Transport}
     */
    public int getTotalConnections() {
        return totalConnectionNumber.get();
    }

    /**
     * Returns the {@link Set} of currently active {@link Connection}s.
     * 
     * @return the {@link Set} of currently active {@link Connection}s
     */
    public Set<Connection> getActiveConnections() {
        return activeConnectionsMap.keySet();
    }
}