helliker.id3
Class ID3v2Frame

java.lang.Object
  helliker.id3.ID3v2Frame

public class ID3v2Frame

extends java.lang.Object

Field Summary

private boolean	compressed
private int	dataLength
private java.lang.String[]	ENC_TYPES
private byte	encrType
private boolean	encrypted
private boolean	fileAlterDiscard
private int	FRAME_FLAGS_SIZE
private int	FRAME_HEAD_SIZE
private byte[]	frameData
private byte	group
private boolean	grouped
private java.lang.String	id
private boolean	lengthIndicator
private int	MAX_EXTRA_DATA
private boolean	readOnly
private boolean	tagAlterDiscard
private boolean	unsynchronised

Constructor Summary

ID3v2Frame(java.lang.String id, byte[] data)
Create and ID3v2 frame with the specified id and data.

ID3v2Frame(java.lang.String id, byte[] data, boolean tagAlterDiscard, boolean fileAlterDiscard, boolean readOnly, boolean grouped, boolean compressed, boolean encrypted, boolean unsynchronised, boolean lengthIndicator)
Create an ID3v2Frame with the specified id, data, and flags set.

ID3v2Frame(java.lang.String id, byte[] flags, byte[] data)
Create an ID3v2Frame with a specified id, a byte array containing the frame header flags, and a byte array containing the data for this frame.

Method Summary

private boolean	checkDefaultFileAlterDiscard() Returns true if this frame should have the file alter preservation bit set by default.
boolean	getCompressed() Returns true if this frame is compressed
int	getDataLength() If a length indicator has been added, the length of the data is returned.
java.lang.String	getDataString() If possible, this method attempts to convert textual part of the data into a string.
private java.lang.String	getDecodedString(byte[] b, int eIndex, int offset) Converts the byte array into a string based on the type of encoding.
boolean	getEncrypted() Returns true if this frame is encrypted
byte	getEncryptionType() If encrypted, this returns the encryption method byte.
private byte[]	getExtraDataBytes() A helper function for the getFrameBytes function that returns an array of all the data contained in any extra fields that may be present in this frame.
boolean	getFileAlterDiscard() Returns true if the file alter preservation bit has been set.
private byte[]	getFlagBytes() A helper function for the getFrameBytes method that processes the info in the frame and returns the 2 byte array of flags to be added to the header.
byte[]	getFrameBytes() Returns a byte array representation of this frame that can be written to a file.
byte[]	getFrameData() Returns the data for this frame
int	getFrameLength() Return the length of this frame in bytes, including the header.
byte	getGroup() Returns the group identifier if added.
boolean	getGrouped() Returns true if this frame is a part of a group
boolean	getLengthIndicator() Returns true if this frame has a length indicator added
boolean	getReadOnly() Returns true if this frame is read only
boolean	getTagAlterDiscard() Returns true if the tag alter preservation bit has been set.
boolean	getUnsynchronised() Returns true if this frame is unsynchronised
boolean	isEmpty() Returns true if there is no data in the frame.
private void	parseData(byte[] data) Pulls out extra information inserted in the frame data depending on what flags are set.
private void	parseFlags(byte[] flags) Read the information from the flags array.
void	setFrameData(byte[] newData) Set the data for this frame.
java.lang.String	toString() Return a string representation of this object that contains all the information contained within it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FRAME_HEAD_SIZE

private final int FRAME_HEAD_SIZE

See Also:

Constant Field Values

FRAME_FLAGS_SIZE

private final int FRAME_FLAGS_SIZE

See Also:

Constant Field Values

MAX_EXTRA_DATA

private final int MAX_EXTRA_DATA

See Also:

Constant Field Values

ENC_TYPES

private final java.lang.String[] ENC_TYPES

id

private java.lang.String id

tagAlterDiscard

private boolean tagAlterDiscard

fileAlterDiscard

private boolean fileAlterDiscard

readOnly

private boolean readOnly

grouped

private boolean grouped

compressed

private boolean compressed

encrypted

private boolean encrypted

unsynchronised

private boolean unsynchronised

lengthIndicator

private boolean lengthIndicator

group

private byte group

encrType

private byte encrType

dataLength

private int dataLength

frameData

private byte[] frameData

Constructor Detail

ID3v2Frame

public ID3v2Frame(java.lang.String id,
                  byte[] flags,
                  byte[] data)
           throws ID3v2FormatException

Create an ID3v2Frame with a specified id, a byte array containing the frame header flags, and a byte array containing the data for this frame.

Parameters:

id - the id of this frame

flags - the flags found in the header of the frame (2 bytes)

data - the data found in this frame

Throws:

ID3v2FormatException - if an error occurs

ID3v2Frame

public ID3v2Frame(java.lang.String id,
                  byte[] data)

Create and ID3v2 frame with the specified id and data. All the flag bits are set to false.

Parameters:

id - the id of this frame

data - the data for this frame

ID3v2Frame

public ID3v2Frame(java.lang.String id,
                  byte[] data,
                  boolean tagAlterDiscard,
                  boolean fileAlterDiscard,
                  boolean readOnly,
                  boolean grouped,
                  boolean compressed,
                  boolean encrypted,
                  boolean unsynchronised,
                  boolean lengthIndicator)

Create an ID3v2Frame with the specified id, data, and flags set. It is expected that the corresponing data for the flags that require extra data is found in the data array in the standard place.

Parameters:

id - the id for this frame

data - the data for this frame

tagAlterDiscard - the tag alter preservation flag

fileAlterDiscard - the file alter preservation flag

readOnly - the read only flag

grouped - the grouping identity flag

compressed - the compression flag

encrypted - the encryption flag

unsynchronised - the unsynchronisation flag

lengthIndicator - the data length indicator flag

Method Detail

checkDefaultFileAlterDiscard

private boolean checkDefaultFileAlterDiscard()

Returns true if this frame should have the file alter preservation bit set by default.

Returns:

true if the file alter preservation should be set by default

parseFlags

private void parseFlags(byte[] flags)
                 throws ID3v2FormatException

Read the information from the flags array.

Parameters:

flags - the flags found in the frame header

Throws:

ID3v2FormatException - if an error occurs

parseData

private void parseData(byte[] data)

Pulls out extra information inserted in the frame data depending on what flags are set.

Parameters:

data - the frame data

getFrameData

public byte[] getFrameData()

Returns the data for this frame

Returns:

the data for this frame

setFrameData

public void setFrameData(byte[] newData)

Set the data for this frame. This does nothing if this frame is read only.

Parameters:

newData - a byte array containing the new data

getFrameLength

public int getFrameLength()

Return the length of this frame in bytes, including the header.

Returns:

the length of this frame

getFrameBytes

public byte[] getFrameBytes()

Returns a byte array representation of this frame that can be written to a file. Includes the header and data.

Returns:

a binary representation of this frame to be written to a file

getFlagBytes

private byte[] getFlagBytes()

A helper function for the getFrameBytes method that processes the info in the frame and returns the 2 byte array of flags to be added to the header.

Returns:

a value of type 'byte[]'

getExtraDataBytes

private byte[] getExtraDataBytes()

A helper function for the getFrameBytes function that returns an array of all the data contained in any extra fields that may be present in this frame. This includes the group, the encryption type, and the length indicator. The length of the array returned is variable length.

Returns:

an array of bytes containing the extra data fields in the frame

getTagAlterDiscard

public boolean getTagAlterDiscard()

Returns true if the tag alter preservation bit has been set. If set then the frame should be discarded if it is altered and the id is unknown.

Returns:

true if the tag alter preservation bit has been set

getFileAlterDiscard

public boolean getFileAlterDiscard()

Returns true if the file alter preservation bit has been set. If set then the frame should be discarded if the file is altered and the id is unknown.

Returns:

true if the file alter preservation bit has been set

getReadOnly

public boolean getReadOnly()

Returns true if this frame is read only

Returns:

true if this frame is read only

getGrouped

public boolean getGrouped()

Returns true if this frame is a part of a group

Returns:

true if this frame is a part of a group

getCompressed

public boolean getCompressed()

Returns true if this frame is compressed

Returns:

true if this frame is compressed

getEncrypted

public boolean getEncrypted()

Returns true if this frame is encrypted

Returns:

true if this frame is encrypted

getUnsynchronised

public boolean getUnsynchronised()

Returns true if this frame is unsynchronised

Returns:

true if this frame is unsynchronised

getLengthIndicator

public boolean getLengthIndicator()

Returns true if this frame has a length indicator added

Returns:

true if this frame has a length indicator added

getGroup

public byte getGroup()

Returns the group identifier if added. Otherwise the null byte is returned.

Returns:

the groupd identifier if added, null byte otherwise

getEncryptionType

public byte getEncryptionType()

If encrypted, this returns the encryption method byte. If it is not encrypted, the null byte is returned.

Returns:

the encryption method if set and the null byte if not

getDataLength

public int getDataLength()

If a length indicator has been added, the length of the data is returned. Otherwise -1 is returned.

Returns:

the length of the data if a length indicator is present or -1

getDecodedString

private java.lang.String getDecodedString(byte[] b,
                                          int eIndex,
                                          int offset)
                                   throws java.io.UnsupportedEncodingException

Converts the byte array into a string based on the type of encoding. One byte in the array should contain the type of encoding. Where it is located is specifed by the eIndex parameter. If an invalid type of encoding is found, the empty string is returned.

Parameters:

b - the array of bytes to convert/decode

eIndex - the index in the array where the encoding type resides

offset - where in the array to start the string

Returns:

the decoded string or an empty string if the encoding is wrong

Throws:

java.io.UnsupportedEncodingException - if an error occurs

getDataString

public java.lang.String getDataString()
                               throws ID3v2FormatException

If possible, this method attempts to convert textual part of the data into a string. If this frame does not contain textual information, an empty string is returned.

Returns:

the textual portion of the data in this frame

Throws:

ID3v2FormatException - if an error occurs

isEmpty

public boolean isEmpty()

Returns true if there is no data in the frame.

Returns:

true if there is no data in the frame

toString

public java.lang.String toString()

Return a string representation of this object that contains all the information contained within it.

Returns:

a string representation of this object