midifilewriter.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)MidiFileWriter.java	1.18 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.sound.midi.spi;		  	 

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;

import javax.sound.midi.Sequence;
import javax.sound.midi.MidiFileFormat;

/**
 * A <code>MidiFileWriter</code> supplies MIDI file-writing services.  Classes 
 * that implement this interface can write one or more types of MIDI file from 
 * a <code>{@link Sequence}</code> object.
 *
 * @author Kara Kytle
 * @version 1.18, 05/11/17
 * @since 1.3
 */
public abstract class MidiFileWriter {


    /**
     * Obtains the set of MIDI file types for which file writing support is 
     * provided by this file writer.
     * @return array of file types.  If no file types are supported, 
     * an array of length 0 is returned.
     */
    public abstract int[] getMidiFileTypes();


    /**
     * Obtains the file types that this file writer can write from the
     * sequence specified.
     * @param sequence the sequence for which MIDI file type support
     * is queried
     * @return array of file types.  If no file types are supported, 
     * returns an array of length 0.
     */
    public abstract int[] getMidiFileTypes(Sequence sequence);


    /**
     * Indicates whether file writing support for the specified MIDI file type 
     * is provided by this file writer.
     * @param fileType the file type for which write capabilities are queried
     * @return <code>true</code> if the file type is supported, 
     * otherwise <code>false</code>
     */
    public boolean isFileTypeSupported(int fileType) {

	int types[] = getMidiFileTypes();
	for(int i=0; i<types.length; i++) {
	    if( fileType == types[i] ) {
		return true;
	    }
	}
	return false;
    }


    /**
     * Indicates whether a MIDI file of the file type specified can be written
     * from the sequence indicated.
     * @param fileType the file type for which write capabilities are queried
     * @param sequence  the sequence for which file writing support is queried
     * @return <code>true</code> if the file type is supported for this sequence, 
     * otherwise <code>false</code>
     */
    public boolean isFileTypeSupported(int fileType, Sequence sequence) {

	int types[] = getMidiFileTypes( sequence );
	for(int i=0; i<types.length; i++) {
	    if( fileType == types[i] ) {
		return true;
	    }
	}
	return false;
    }


    /**
     * Writes a stream of bytes representing a MIDI file of the file type
     * indicated to the output stream provided. 
     * @param in sequence containing MIDI data to be written to the file
     * @param fileType type of the file to be written to the output stream
     * @param out stream to which the file data should be written
     * @return the number of bytes written to the output stream
     * @throws IOException if an I/O exception occurs
     * @throws IllegalArgumentException if the file type is not supported by
     * this file writer
     * @see #isFileTypeSupported(int, Sequence)
     * @see	#getMidiFileTypes(Sequence)
     */
    public abstract int write(Sequence in, int fileType, OutputStream out) throws IOException;


    /**
     * Writes a stream of bytes representing a MIDI file of the file type
     * indicated to the external file provided.
     * @param in sequence containing MIDI data to be written to the external file
     * @param fileType type of the file to be written to the external file
     * @param out external file to which the file data should be written
     * @return the number of bytes written to the file
     * @throws IOException if an I/O exception occurs
     * @throws IllegalArgumentException if the file type is not supported by
     * this file writer
     * @see #isFileTypeSupported(int, Sequence)
     * @see	#getMidiFileTypes(Sequence)
     */
    public abstract int write(Sequence in, int fileType, File out) throws IOException;
}