mp3file.java

java声音播放管理

    /**
     * Set the track number of this mp3.
     *
     * @param track the track number of this mp3
     */
    public void setTrack( int track ) {
	if( allow( ID3V1 ) ) {
	    id3v1.setTrack( track );
	}
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( ID3v2Frames.TRACK_NUMBER, 
				String.valueOf(track) );
	}
    }

    /**
     * Set the composer of this mp3 (id3v2 only).
     *
     * @param composer the composer of this mp3
     */
    public void setComposer( String composer ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( ID3v2Frames.COMPOSER, composer );
	}
    }

    /**
     * Set the original artist of this mp3 (id3v2 only).
     *
     * @param artist the original artist of this mp3
     */
    public void setOriginalArtist( String artist ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( ID3v2Frames.ORIGINAL_ARTIST, artist );
	}
    }

    /**
     * Add some copyright information to this mp3 (id3v2 only).
     *
     * @param copyright copyright information related to this mp3
     */
    public void setCopyrightInfo( String copyright ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( ID3v2Frames.COPYRIGHT_MESSAGE, copyright );
	}
    }

    /**
     * Add a link to this mp3 (id3v2 only).  This includes a description of 
     * the url and the url itself.
     *
     * @param desc a description of the url
     * @param url the url itself
     */
    public void setUserDefinedURL( String desc, String url ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setUserDefinedURLFrame( desc, url );
	}
    }

    /**
     * Add a field of miscellaneous text (id3v2 only).  This includes a 
     * description of the text and the text itself.
     *
     * @param desc a description of the text
     * @param text the text itself
     */
    public void setUserDefinedText( String desc, String text ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setUserDefinedTextFrame( desc, text );
	}
    }

    /**
     * Set who encoded the mp3 (id3v2 only).
     *
     * @param encBy who encoded the mp3
     */
    public void setEncodedBy( String encBy ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( ID3v2Frames.ENCODED_BY, encBy );
	}
    }

    /**
     * Set the text of the text frame specified by the id (id3v2 only).  The
     * id should be one of the static strings specifed in ID3v2Frames class.
     * All id's that begin with 'T' (excluding "TXXX") are considered text
     * frames.
     *
     * @param id the id of the frame to set the data for
     * @param data the data to set
     */
    public void setTextFrame( String id, String data ) {
	if( allow( ID3V2 ) ) {
	    id3v2.setTextFrame( id, data );
	}
    }

    /**
     * Set the data of the frame specified by the id (id3v2 only).  The id 
     * should be one of the static strings specified in ID3v2Frames class.
     *
     * @param id the id of the frame to set the data for
     * @param data the data to set
     */
    public void setFrameData( String id, byte[] data ) {
	if( allow( ID3V2 ) ) {
	    id3v2.updateFrameData( id, data );
	}
    }

    /**
     * Returns the artist of the mp3 if set and the empty string if not.
     *
     * @return the artist of the mp3
     * @exception ID3v2FormatException if the data of the field is incorrect
     */
    public String getArtist() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.LEAD_PERFORMERS );
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getArtist();
	}

	return str;
    }

    /**
     * Returns the album of the mp3 if set and the empty string if not.
     *
     * @return the album of the mp3
     * @exception ID3v2FormatException if the data of the field is incorrect
     */
    public String getAlbum() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.ALBUM );
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getAlbum();
	}

	return str;
    }

    /**
     * Returns the comment field of this mp3 if set and the empty string if
     * not.
     *
     * @return the comment field of this mp3
     * @exception ID3v2FormatException if the data of the field is incorrect
     */
    public String getComment() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.COMMENTS );
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getComment();
	}

	return str;
    }

    /**
     * Returns the genre of this mp3 if set and the empty string if not.
     *
     * @return the genre of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getGenre() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.CONTENT_TYPE );
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getGenreString();
	}

	return str;
    }

    /**
     * Returns the title of this mp3 if set and the empty string if not.
     *
     * @return the title of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getTitle() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.TITLE );
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getTitle();
	}

	return str;
    }

    /**
     * Returns the track of this mp3 if set and the empty string if not.
     *
     * @return the track of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getTrack() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.TRACK_NUMBER );
	}
	else if( allow( ID3V1) ) {
	    str = String.valueOf( id3v1.getTrack() );
	}

	return str;
    }

    /**
     * Returns the year of this mp3 if set and the empty string if not.
     *
     * @return the year of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getYear() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.YEAR);
	}
	else if( allow( ID3V1) ) {
	    str = id3v1.getYear();
	}

	return str;
    }

    /**
     * Returns the composer of this mp3 if set and the empty string if not
     * (id3v2 only).
     *
     * @return the composer of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getComposer() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.COMPOSER );
	}

	return str;
    }

    /**
     * Returns the original artist of this mp3 if set and the empty string
     * if not (id3v2 only).
     *
     * @return the original artist of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getOriginalArtist() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.ORIGINAL_ARTIST );
	}

	return str;
    }

    /**
     * Returns the copyright info of this mp3 if set and the empty string
     * if not (id3v2 only).
     *
     * @return the copyright info of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getCopyrightInfo() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.COPYRIGHT_MESSAGE );
	}

	return str;
    }

    /**
     * Returns the user defined url of this mp3 if set and the empty string
     * if not (id3v2 only).
     *
     * @return the user defined url of this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getUserDefinedURL() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.USER_DEFINED_URL );
	}

	return str;
    }

    /**
     * Returns who encoded this mp3 if set and the empty string if not 
     * (id3v2 only).
     *
     * @return who encoded this mp3
     * @exception ID3v2FormatException if the data of this field is incorrect
     */
    public String getEncodedBy() throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( ID3v2Frames.ENCODED_BY );
	}

	return str;
    }

    /**
     * Returns the textual information contained in the frame specifed by the
     * id.  If the frame does not contain any textual information or does not
     * exist, then the empty string is returned (id3v2 only).  The id should 
     * be one of the static strings defined in the ID3v2Frames class.
     *
     * @param id the id of the frame to get data from
     * @return the textual information of the frame
     * @exception ID3v2FormatException if the data of the frame is incorrect
     */
    public String getFrameDataString( String id ) throws ID3v2FormatException {
	String str = new String();

	if( allow( ID3V2 ) ) {
	    str = id3v2.getFrameDataString( id );
	}

	return str;
    }

    /**
     * Returns the data contained in the frame specified by the id (id3v2 only)
     * .  If the frame does not exist, a zero length array will be returned.
     * The id should be one of the static strings defined in the ID3v2Frames
     * class.
     *
     * @param id the id of the frame to get data from
     * @return the data contained in the frame
     */
    public byte[] getFrameDataBytes( String id ) {
	byte[] b = new byte[0];
	
	if( allow( ID3V2 ) ) {
	    b = id3v2.getFrameData( id );
	}

	return b;
    }

    /**
     * Returns the currently set tagging type.
     *
     * @return the current tagging type
     */
    public int getTaggingType() {
	return tagType;
    }

    /**
     * Set the tagging type.  This determines what type of id3 tags are 
     * read/written.  This should be one of the constants defined by this
     * class: BOTH_TAGS, ID3V1_ONLY, ID3V2_ONLY, EXISTING_TAGS_ONLY, NO_TAGS
     *
     * @param newType the new tagging type
     */
    public void setTaggingType( int newType ) {
	tagType = newType;
    }

    /**
     * Checks whether it is ok to read or write from the tag version specified
     * based on the tagType passed to the constructor.  The tagVersion 
     * parameter should be either ID3V1 or ID3V2.
     *
     * @param tagVersion the id3 version to check
     * @return true if it is ok to proceed with the read/write
     */
    private boolean allow( int tagVersion ) {
	return this.allow( tagVersion, tagType );
    }

    /**
     * Checks whether it is ok to read or write from the tag version specified
     * based on the tagType passed to the method.  The tagVersion parameter
     * should be either ID3V1 or ID3V2.  The type parameter should be either
     * BOTH_TAGS, ID3V1_ONLY, ID3V2_ONLY, NO_TAGS, or EXISTING_TAGS_ONLY.
     *
     * @param tagVersion the id3 version to check
     * @param type specifies what conditions the tags are allowed to proceed
     * @return true if it is ok to proceed with the read/write
     */
    private boolean allow( int tagVersion, int type ) {
	boolean retval = false;

	if( tagVersion == ID3V1 ) {
	    retval = ((type == EXISTING_TAGS_ONLY) && id3v1.tagExists()) || 
		(type == ID3V1_ONLY) || (type == BOTH_TAGS);
	}
	else if( tagVersion == ID3V2 ) {
	    retval = ((type == EXISTING_TAGS_ONLY) && id3v2.tagExists()) || 
		(type == ID3V2_ONLY) || (type == BOTH_TAGS);
	}

	return retval;
    }

    /**
     * Return a string representation of this object.  This includes all the 
     * information contained within the mpeg header and id3 tags as well as
     * certain file attributes.
     *
     * @return a string representation of this object
     */
    public String toString() {
	return "MP3File" + "\nPath:\t\t\t\t" + mp3.getAbsolutePath() + 
	    "\nFileSize:\t\t\t" + mp3.length() + " bytes\nPlayingTime:\t\t\t" 
	    + getPlayingTimeString() + "\n" + head + "\n" + id3v1 + "\n" + 
	    id3v2;
    }

    /**
     * Returns true if the object o is equal to this MP3File.
     *
     * @param o the object to compare
     * @return true if the object o is equal to this MP3File
     */
    public boolean equals( Object o ) {
	return mp3.equals( o );
    }

    /**
     * Compare this MP3File to the specified object.  The comparison 
     * implementation comes from the MP3Comparator class, look there for
     * details on the comparison method.
     *
     * @param o the object to compare to this one
     * @return a positive number if this object is greater than the other,
     *         0 if the object are equal, or a negative number if this object
     *         is less than the other
     */
    public int compareTo( Object o ) {
	return comparator.compare( this, o );
    }

} // MP3File