/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.sshd.server.command;

import java.io.IOException;

import org.apache.sshd.server.Environment;
import org.apache.sshd.server.channel.ChannelSession;

/**
 * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
 */
public interface CommandLifecycle {
    /**
     * Starts the command execution. All streams must have been set <U>before</U> calling this method. The command
     * should implement {@link java.lang.Runnable}, and this method should spawn a new thread like:
     *
     * <pre>
     * {@code
     * Thread(this).start();
     * }
     * </pre>
     *
     * @param  channel     The {@link ChannelSession} through which the command has been received
     * @param  env         The {@link Environment}
     * @throws IOException If failed to start
     */
    void start(ChannelSession channel, Environment env) throws IOException;

    /**
     * This method is called by the SSH server to destroy the command because the client has disconnected somehow.
     *
     * @param  channel   The {@link ChannelSession} through which the command has been received
     * @throws Exception if failed to destroy
     */
    void destroy(ChannelSession channel) throws Exception;
}
