/*
 * OperationFactory.java February 2007
 *
 * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
 *
 * 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 org.simpleframework.transport;

import java.io.IOException;

import javax.net.ssl.SSLEngine;

import org.simpleframework.transport.reactor.Operation;

/**
 * The <code>OperationFactory</code> is used to create operations for the
 * transport processor. Depending on the configuration of the pipeline object
 * this will create different operations. Typically this will create an SSL
 * handshake operation if the pipeline has an <code>SSLEngine</code> instance.
 * This allows the transport processor to complete the handshake before handing
 * the transport to the transporter for processing.
 * 
 * @author Niall Gallagher
 */
class OperationFactory {

    /**
     * This is the negotiator used to process the created transport.
     */
    private final Negotiator negotiator;

    /**
     * This is the threshold for the asynchronous buffers to use.
     */
    private final int limit;

    /**
     * Constructor for the <code>OperationFactory</code> object. This uses the
     * negotiator provided to hand off the created transport when it has been
     * created. All operations created typically execute in an asynchronous
     * thread.
     * 
     * @param negotiator
     *            the negotiator used to process transports
     * @param limit
     *            this is the threshold for asynchronous buffers
     */
    public OperationFactory(Negotiator negotiator, int limit) {
        this.negotiator = negotiator;
        this.limit = limit;
    }

    /**
     * This method is used to create <code>Operation</code> object to process
     * the next phase of the negotiation. The operations that are created using
     * this factory ensure the processing can be done asynchronously, which
     * reduces the overhead the connection thread has when handing the pipelines
     * over for processing.
     * 
     * @param socket
     *            this is the pipeline that is to be processed
     * 
     * @return this returns the operation used for processing
     */
    public Operation getInstance(Socket socket) throws IOException {
        return this.getInstance(socket, socket.getEngine());
    }

    /**
     * This method is used to create <code>Operation</code> object to process
     * the next phase of the negotiation. The operations that are created using
     * this factory ensure the processing can be done asynchronously, which
     * reduces the overhead the connection thread has when handing the pipelines
     * over for processing.
     * 
     * @param socket
     *            this is the pipeline that is to be processed
     * @param engine
     *            this is the engine used for SSL negotiations
     * 
     * @return this returns the operation used for processing
     */
    private Operation getInstance(Socket socket, SSLEngine engine)
            throws IOException {
        Transport transport = new SocketTransport(socket, this.negotiator,
                this.limit);

        if (engine != null) return new Handshake(transport, this.negotiator);
        return new Dispatcher(transport, this.negotiator);
    }
}