io.nayuki.qrcodegen

Class QrSegment

java.lang.Object

io.nayuki.qrcodegen.QrSegment

public final class QrSegment
extends Object

Represents a character string to be encoded in a QR Code symbol. Each segment has a mode, and a sequence of characters that is already encoded as a sequence of bits. Instances of this class are immutable.

This segment class imposes no length restrictions, but QR Codes have restrictions. Even in the most favorable conditions, a QR Code can only hold 7089 characters of data. Any segment longer than this is meaningless for the purpose of generating QR Codes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QrSegment.Mode The mode field of a segment.

Field Summary

Fields

Modifier and Type	Field and Description
static Pattern	ALPHANUMERIC_REGEX Can test whether a string is encodable in alphanumeric mode (such as by using makeAlphanumeric(String)).
QrSegment.Mode	mode The mode indicator for this segment.
int	numChars The length of this segment's unencoded data, measured in characters.
static Pattern	NUMERIC_REGEX Can test whether a string is encodable in numeric mode (such as by using makeNumeric(String)).

Constructor Summary

Constructors

Constructor and Description
QrSegment(QrSegment.Mode md, int numCh, BitBuffer data) Creates a new QR Code data segment with the specified parameters and data.

Method Summary

Modifier and Type	Method and Description
BitBuffer	getBits() Returns the data bits of this segment.
static QrSegment	makeAlphanumeric(String text) Returns a segment representing the specified text string encoded in alphanumeric mode.
static QrSegment	makeBytes(byte[] data) Returns a segment representing the specified binary data encoded in byte mode.
static QrSegment	makeEci(int assignVal) Returns a segment representing an Extended Channel Interpretation (ECI) designator with the specified assignment value.
static QrSegment	makeNumeric(String digits) Returns a segment representing the specified string of decimal digits encoded in numeric mode.
static List<QrSegment>	makeSegments(String text) Returns a new mutable list of zero or more segments to represent the specified Unicode text string.

Methods inherited from class java.lang.Object

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

Field Detail

mode

public final QrSegment.Mode mode

The mode indicator for this segment. Never null.

numChars

public final int numChars

The length of this segment's unencoded data, measured in characters. Always zero or positive.

NUMERIC_REGEX

public static final Pattern NUMERIC_REGEX

Can test whether a string is encodable in numeric mode (such as by using makeNumeric(String)).

ALPHANUMERIC_REGEX

public static final Pattern ALPHANUMERIC_REGEX

Can test whether a string is encodable in alphanumeric mode (such as by using makeAlphanumeric(String)).

Constructor Detail

QrSegment

public QrSegment(QrSegment.Mode md,
                 int numCh,
                 BitBuffer data)

Creates a new QR Code data segment with the specified parameters and data.

Parameters:

md - the mode, which is not null

numCh - the data length in characters, which is non-negative

data - the data bits of this segment, which is not null

Throws:

NullPointerException - if the mode or bit buffer is null

IllegalArgumentException - if the character count is negative

Method Detail

makeBytes

public static QrSegment makeBytes(byte[] data)

Returns a segment representing the specified binary data encoded in byte mode.

Parameters:

data - the binary data

Returns:

a segment containing the data

Throws:

NullPointerException - if the array is null

makeNumeric

public static QrSegment makeNumeric(String digits)

Returns a segment representing the specified string of decimal digits encoded in numeric mode.

Parameters:

digits - a string consisting of digits from 0 to 9

Returns:

a segment containing the data

Throws:

NullPointerException - if the string is null

IllegalArgumentException - if the string contains non-digit characters

makeAlphanumeric

public static QrSegment makeAlphanumeric(String text)

Returns a segment representing the specified text string encoded in alphanumeric mode. The characters allowed are: 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.

Parameters:

text - a string of text, with only certain characters allowed

Returns:

a segment containing the data

Throws:

NullPointerException - if the string is null

IllegalArgumentException - if the string contains non-encodable characters

makeSegments

public static List<QrSegment> makeSegments(String text)

Returns a new mutable list of zero or more segments to represent the specified Unicode text string. The result may use various segment modes and switch modes to optimize the length of the bit stream.

Parameters:

text - the text to be encoded, which can be any Unicode string

Returns:

a list of segments containing the text

Throws:

NullPointerException - if the text is null

makeEci

public static QrSegment makeEci(int assignVal)

Returns a segment representing an Extended Channel Interpretation (ECI) designator with the specified assignment value.

Parameters:

assignVal - the ECI assignment number (see the AIM ECI specification)

Returns:

a segment containing the data

Throws:

IllegalArgumentException - if the value is outside the range [0, 10⁶)

getBits

public BitBuffer getBits()

Returns the data bits of this segment.

Returns:

the data bits of this segment (not null)