/*
 * Copyright (c) 2008-2009, Motorola, Inc.
 *
 * 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 the Motorola, Inc. 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 HOLDER 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.
 */

package javax.obex;

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

/**
 * The <code>Operation</code> interface provides ways to manipulate a single
 * OBEX PUT or GET operation. The implementation of this interface sends OBEX
 * packets as they are built. If during the operation the peer in the operation
 * ends the operation, an <code>IOException</code> is thrown on the next read
 * from the input stream, write to the output stream, or call to
 * <code>sendHeaders()</code>.
 * <P>
 * <STRONG>Definition of methods inherited from <code>ContentConnection</code>
 * </STRONG>
 * <P>
 * <code>getEncoding()</code> will always return <code>null</code>. <BR>
 * <code>getLength()</code> will return the length specified by the OBEX Length
 * header or -1 if the OBEX Length header was not included. <BR>
 * <code>getType()</code> will return the value specified in the OBEX Type
 * header or <code>null</code> if the OBEX Type header was not included.<BR>
 * <P>
 * <STRONG>How Headers are Handled</STRONG>
 * <P>
 * As headers are received, they may be retrieved through the
 * <code>getReceivedHeaders()</code> method. If new headers are set during the
 * operation, the new headers will be sent during the next packet exchange.
 * <P>
 * <STRONG>PUT example</STRONG>
 * <P>
 * <PRE>
 * void putObjectViaOBEX(ClientSession conn, HeaderSet head, byte[] obj) throws IOException {
 *     // Include the length header
 *     head.setHeader(head.LENGTH, new Long(obj.length));
 *     // Initiate the PUT request
 *     Operation op = conn.put(head);
 *     // Open the output stream to put the object to it
 *     DataOutputStream out = op.openDataOutputStream();
 *     // Send the object to the server
 *     out.write(obj);
 *     // End the transaction
 *     out.close();
 *     op.close();
 * }
 * </PRE>
 * <P>
 * <STRONG>GET example</STRONG>
 * <P>
 * <PRE>
 * byte[] getObjectViaOBEX(ClientSession conn, HeaderSet head) throws IOException {
 *     // Send the initial GET request to the server
 *     Operation op = conn.get(head);
 *     // Retrieve the length of the object being sent back
 *     int length = op.getLength();
 *     // Create space for the object
 *     byte[] obj = new byte[length];
 *     // Get the object from the input stream
 *     DataInputStream in = trans.openDataInputStream();
 *     in.read(obj);
 *     // End the transaction
 *     in.close();
 *     op.close();
 *     return obj;
 * }
 * </PRE>
 *
 * <H3>Client PUT Operation Flow</H3> For PUT operations, a call to
 * <code>close()</code> the <code>OutputStream</code> returned from
 * <code>openOutputStream()</code> or <code>openDataOutputStream()</code> will
 * signal that the request is done. (In OBEX terms, the End-Of-Body header
 * should be sent and the final bit in the request will be set.) At this point,
 * the reply from the server may begin to be processed. A call to
 * <code>getResponseCode()</code> will do an implicit close on the
 * <code>OutputStream</code> and therefore signal that the request is done.
 * <H3>Client GET Operation Flow</H3> For GET operation, a call to
 * <code>openInputStream()</code> or <code>openDataInputStream()</code> will
 * signal that the request is done. (In OBEX terms, the final bit in the request
 * will be set.) A call to <code>getResponseCode()</code> will cause an implicit
 * close on the <code>InputStream</code>. No further data may be read at this
 * point.
 * @hide
 */
public interface Operation {

    /**
     * Sends an ABORT message to the server. By calling this method, the
     * corresponding input and output streams will be closed along with this
     * object. No headers are sent in the abort request. This will end the
     * operation since <code>close()</code> will be called by this method.
     * @throws IOException if the transaction has already ended or if an OBEX
     *         server calls this method
     */
    void abort() throws IOException;

    /**
     * Returns the headers that have been received during the operation.
     * Modifying the object returned has no effect on the headers that are sent
     * or retrieved.
     * @return the headers received during this <code>Operation</code>
     * @throws IOException if this <code>Operation</code> has been closed
     */
    HeaderSet getReceivedHeader() throws IOException;

    /**
     * Specifies the headers that should be sent in the next OBEX message that
     * is sent.
     * @param headers the headers to send in the next message
     * @throws IOException if this <code>Operation</code> has been closed or the
     *         transaction has ended and no further messages will be exchanged
     * @throws IllegalArgumentException if <code>headers</code> was not created
     *         by a call to <code>ServerRequestHandler.createHeaderSet()</code>
     *         or <code>ClientSession.createHeaderSet()</code>
     * @throws NullPointerException if <code>headers</code> if <code>null</code>
     */
    void sendHeaders(HeaderSet headers) throws IOException;

    /**
     * Returns the response code received from the server. Response codes are
     * defined in the <code>ResponseCodes</code> class.
     * @see ResponseCodes
     * @return the response code retrieved from the server
     * @throws IOException if an error occurred in the transport layer during
     *         the transaction; if this object was created by an OBEX server
     */
    int getResponseCode() throws IOException;

    String getEncoding();

    long getLength();

    int getHeaderLength();

    String getType();

    InputStream openInputStream() throws IOException;

    DataInputStream openDataInputStream() throws IOException;

    OutputStream openOutputStream() throws IOException;

    DataOutputStream openDataOutputStream() throws IOException;

    void close() throws IOException;

    int getMaxPacketSize();
}