Here's an update to my earlier post, An Intro to jid3rL. The classes and constructors have changed to:

Tag2(Version version)
Tag2Header(Version version, Tag2HeaderFlags flags, int tagLength)
Tag2HeaderFlags(Version version, byte flags)

abstract Tag2ExtendedHeader(int paddingLength, byte[] crc)
Tag2ExtendedHeaderPoint3(int paddingLength, byte[] crc)

abstract FrameHeader(String id, int frameLength)
FrameHeaderPoint2(String id, int frameLength)
FrameHeaderPoint3(String id, int frameLength)

Language(String code, String description)
Version(byte code, String description)

abstract Frame(Version version, String id)
TextInformationFrame(Version version, String id, EncodedString information)
CommentsFrame(Version version, String id, TextEncoding encoding, Language language, String description, String text)
UniqueFileIdentifierFrame(Version version, String id, String ownerIdentifier, byte[] identifier)
UserDefinedLinkFrame(Version version, String id, EncodedString description, String url)
UnsupportedFrame(Version version, String id, byte[] payload)

FramesGroup()
Hierarchy()

abstract Id3v2Segment()

TextEncoding(byte code, String desc)
EncodedString(TextEncoding encoding, String text)
EncodedString(TextEncoding encoding, byte[] buffer)

ByteArrayTools()

Colour legend

public class
package visible class
private constructor

Keep in mind that the green (public) classes are the only ones accessible to users of the library. This is a update of the older explanation of these classes, which you might want to read first.

I made the two "constant" classes I talked about last time. These types of classes are used because Java doesn't have enumerations -- yet. They limit the range of input on a parameter and simplify testing. Those two classes are Version and Language.

There are only three Version instances: 2.2, 2.3 and 2.4. The byte used in the private constructor are just the minor version numbers 2, 3 and 4. The Language class has contants for all 500 or so languages in ISO-639-2. Yes, it took quite a bit of tedious/brainless typing to make this class! To improve readability I didn't capitalize the Language constants, so English is Language.English. Language is only used in CommentsFrame so far.

Before I fixed my flag reading code I thought I was going to have to read id3v2 tag extended headers. Turns out the test files I have don't have extended headers but I'm going to save this work anyway.

To simplify the Tag2 class I took all of the frame-related methods out of it and made a new class: FramesGroup. FramesGroup uses the Hierarchy class I blogged about yesterday to organize frames. Tag2 only has one FramesGroup.