/*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package javax.microedition.media.protocol;
import java.io.IOException;
import javax.microedition.media.Controllable;
/**
* Abstracts a single stream of media data. It is used in
* conjunction with <code>DataSource</code> to provide the
* input interface to a <code>Player</code>
* <p>
* SourceStream may provide type-specific controls. For that
* reason, it implements the <code>Controllable</code> interface
* to provide additional controls.
*
* @see DataSource
*
*/
public interface SourceStream extends Controllable {
/**
* The value returned by <code>getSeekType</code> indicating that this
* <code>SourceStream</code> is not seekable.
* <p>
* Value 0 is assigned to <code>NOT_SEEKABLE</code>.
*/
int NOT_SEEKABLE = 0;
/**
* The value returned by <code>getSeekType</code> indicating that this
* <code>SourceStream</code> can be seeked only to the beginning
* of the media stream.
* <p>
* Value 1 is assigned to <code>SEEKABLE_TO_START</code>.
*/
int SEEKABLE_TO_START = 1;
/**
* The value returned by <code>getSeekType</code> indicating that this
* <code>SourceStream</code> can be seeked anywhere within the media.
* <p>
* Value 2 is assigned to <code>RANDOM_ACCESSIBLE</code>.
*/
int RANDOM_ACCESSIBLE = 2;
/**
* Get the content type for this stream.
*
* @return The current <CODE>ContentDescriptor</CODE> for this stream.
*/
ContentDescriptor getContentDescriptor();
/**
* Get the size in bytes of the content on this stream.
*
* @return The content length in bytes. -1 is returned if the
* length is not known.
*/
long getContentLength();
/**
* Reads up to <code>len</code> bytes of data from the input stream into
* an array of bytes. An attempt is made to read as many as
* <code>len</code> bytes, but a smaller number may be read.
* The number of bytes actually read is returned as an integer.
*
* <p> This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
* <p> If <code>b</code> is <code>null</code>, a
* <code>NullPointerException</code> is thrown.
*
* <p> If <code>off</code> is negative, or <code>len</code> is negative, or
* <code>off+len</code> is greater than the length of the array
* <code>b</code>, then an <code>IndexOutOfBoundsException</code> is
* thrown.
*
* <p> If <code>len</code> is zero, then no bytes are read and
* <code>0</code> is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at end of
* file, the value <code>-1</code> is returned; otherwise, at least one
* byte is read and stored into <code>b</code>.
*
* <p> The first byte read is stored into element <code>b[off]</code>, the
* next one into <code>b[off+1]</code>, and so on. The number of bytes read
* is, at most, equal to <code>len</code>. Let <i>k</i> be the number of
* bytes actually read; these bytes will be stored in elements
* <code>b[off]</code> through <code>b[off+</code><i>k</i><code>-1]</code>,
* leaving elements <code>b[off+</code><i>k</i><code>]</code> through
* <code>b[off+len-1]</code> unaffected.
*
* <p> If the first byte cannot be read for any reason other than end of
* file, then an <code>IOException</code> is thrown. In particular, an
* <code>IOException</code> is thrown if the input stream has been closed.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array <code>b</code>
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* <code>-1</code> if there is no more data because the end of
* the stream has been reached.
* @exception IOException if an I/O error occurs.
*/
int read(byte[] b, int off, int len)
throws IOException;
/**
* Get the size of a "logical" chunk of media data from the source.
* This method can be used to determine the minimum size of the
* buffer to use in conjunction with the <code>read</code> method
* to read data from the source.
*
* @return The minimum size of the buffer needed to read a "logical"
* chunk of data from the source. Returns -1 if the size cannot be
* determined.
* @see #read(byte[], int, int)
*/
int getTransferSize();
/**
* Seek to the specified point in the stream. The <code>seek</code>
* method may, for a variety of reasons, fail to seek to the specified
* position. For example,
* it may be asked to seek to a position beyond the size of the stream;
* or the stream may only be seekable to the beginning
* (<code>getSeekType</code> returns <code>SEEKABLE_TO_START</code>).
* The return value indicates whether the seeking is successful.
* If it is successful, the value returned will be the same as the
* given position. Otherwise, the return value will indicate what
* the new position is.
* <p>
* If the given position is negative, seek will treat that as 0
* and attempt to seek to 0.
* <p>
* An IOException will be thrown if an I/O error occurs, e.g. when
* the stream comes from a remote connection and the connection is
* broken.
*
* @param where The position to seek to.
* @return The new stream position.
* @exception IOException Thrown if an I/O error occurs.
*/
long seek(long where) throws IOException;
/**
* Obtain the current position in the stream.
* @return The current position in the stream.
*/
long tell();
/**
* Find out if the stream is seekable.
* The return value can be one of these three:
* <code>NOT_SEEKABLE</code>, <code>SEEKABLE_TO_START</code> and
* <code>RANDOM_ACCESSIBLE</code>.
* If the return value is <code>SEEKABLE_TO_START</code>, it means
* that the stream can only be repositioned to the beginning of
* the stream. If the return value is <code>RANDOM_ACCESSIBLE</code>,
* the stream can be seeked anywhere within the stream.
*
* @return Returns an enumerated value to indicate the level of seekability.
*/
int getSeekType();
}
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