/*

 * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *   - Neither the name of Oracle nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * This source code is provided to illustrate the usage of a given feature

 * or technique and has been deliberately simplified. Additional steps

 * required for a production-quality application, such as security checks,

 * input validation and proper error handling, might not be present in

 * this sample code.

 */

import java.io.*;

import java.net.*;

import java.nio.channels.*;

import java.nio.charset.*;

/**

 * A Content type that provides for transferring files.

 *

 * @author Mark Reinhold

 * @author Brad R. Wetmore

 */

class FileContent implements Content {

    private static File ROOT = new File("root");

    private File fn;

    FileContent(URI uri) {

        fn = new File(ROOT,

                      uri.getPath()

                      .replace('/',

                               File.separatorChar));

    }

    private String type = null;

    public String type() {

        if (type != null)

            return type;

        String nm = fn.getName();

        if (nm.endsWith(".html"))

            type = "text/html; charset=iso-8859-1";

        else if ((nm.indexOf('.') < 0) || nm.endsWith(".txt"))

            type = "text/plain; charset=iso-8859-1";

        else

            type = "application/octet-stream";

        return type;

    }

    private FileChannel fc = null;

    private long length = -1;

    private long position = -1;         // NB only; >= 0 if transferring

    public long length() {

        return length;

    }

    public void prepare() throws IOException {

        if (fc == null)

            fc = new RandomAccessFile(fn, "r").getChannel();

        length = fc.size();

        position = 0;                   // NB only

    }

    public boolean send(ChannelIO cio) throws IOException {

        if (fc == null)

            throw new IllegalStateException();

        if (position < 0)               // NB only

            throw new IllegalStateException();

        /*

         * Short-circuit if we're already done.

         */

        if (position >= length) {

            return false;

        }

        position += cio.transferTo(fc, position, length - position);

        return (position < length);

    }

    public void release() throws IOException {

        if (fc != null) {

            fc.close();

            fc = null;

        }

    }

}