/* 
 * 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.commons.exec;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Used by {@code Execute} to handle input and output stream of
 * subprocesses.
 *
 */
public interface ExecuteStreamHandler {

    /**
     * Install a handler for the input stream of the subprocess.
     * 
     * @param os
     *            output stream to write to the standard input stream of the subprocess
     * @throws IOException
     *             thrown when an I/O exception occurs.
     */
    void setProcessInputStream(OutputStream os) throws IOException;

    /**
     * Install a handler for the error stream of the subprocess.
     * 
     * @param is
     *            input stream to read from the error stream from the subprocess
     * @throws IOException
     *             thrown when an I/O exception occurs.
     */
    void setProcessErrorStream(InputStream is) throws IOException;

    /**
     * Install a handler for the output stream of the subprocess.
     * 
     * @param is
     *            input stream to read from the error stream from the subprocess
     * @throws IOException
     *             thrown when an I/O exception occurs.
     */
    void setProcessOutputStream(InputStream is) throws IOException;

    /**
     * Start handling of the streams.
     * 
     * @throws IOException
     *             thrown when an I/O exception occurs.
     */
    void start() throws IOException;

    /**
     * Stop handling of the streams - will not be restarted. Will wait for pump threads to complete.
     * 
     * @throws IOException
     *             thrown when an I/O exception occurs.
     */
    void stop() throws IOException;
}