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class:HexFormat [NONE]
public final class HexFormatextends Object
HexFormat converts between bytes and chars and hex-encoded strings which may include additional formatting markup such as prefixes, suffixes, and delimiters.

There are two factories of HexFormat with preset parameters of() and ofDelimiter(delimiter). For other parameter combinations the withXXX methods return copies of HexFormat modified withPrefix(String), withSuffix(String), withDelimiter(String) or choice of withUpperCase() or withLowerCase() parameters.

For primitive to hexadecimal string conversions the toHexDigits methods include toHexDigits(byte), toHexDigits(int), and toHexDigits(long), etc. The default is to use lowercase characters "0-9","a-f". For conversions producing uppercase hexadecimal the characters are "0-9","A-F". Only the HexFormat.isUpperCase() parameter is considered; the delimiter, prefix and suffix are not used.

For hexadecimal string to primitive conversions the fromHexDigits methods include fromHexDigits(string), fromHexDigitsToLong(string), and fromHexDigit(int) converts a single character or codepoint. For conversions from hexadecimal characters the digits and uppercase and lowercase characters in "0-9", "a-f", and "A-F" are converted to corresponding values 0-15. The delimiter, prefix, suffix, and uppercase parameters are not used.

For byte array to formatted hexadecimal string conversions the formatHex methods include formatHex(byte[]) and formatHex(Appendable, byte[]) . The formatted output is a string or is appended to an Appendable such as StringBuilder or PrintStream. Each byte value is formatted as the prefix, two hexadecimal characters from the uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. For conversions producing uppercase hexadecimal strings use withUpperCase().

For formatted hexadecimal string to byte array conversions the parseHex methods include parseHex(CharSequence) and parseHex(char[], offset, length) . Each byte value is parsed from the prefix, two case insensitive hexadecimal characters, and the suffix. A delimiter follows each formatted value, except the last.

API Note:
For example, an individual byte is converted to a string of hexadecimal digits using toHexDigits(int) and converted from a string to a primitive value using fromHexDigits(string).

     HexFormat hex = HexFormat.of();
     byte b = 127;
     String byteStr = hex.toHexDigits(b);

     byte byteVal = (byte)hex.fromHexDigits(byteStr);
     assert(byteStr.equals("7f"));
     assert(b == byteVal);

     // The hexadecimal digits are: "7f"

For a comma (", " ) separated format with a prefix ("#") using lowercase hex digits the HexFormat is:


     HexFormat commaFormat = HexFormat.ofDelimiter(", ").withPrefix("#");
     byte[] bytes = {0, 1, 2, 3, 124, 125, 126, 127};
     String str = commaFormat.formatHex(bytes);

     byte[] parsed = commaFormat.parseHex(str);
     assert(Arrays.equals(bytes, parsed));

     // The formatted string is: "#00, #01, #02, #03, #7c, #7d, #7e, #7f"

For a fingerprint of byte values that uses the delimiter colon (":") and uppercase characters the HexFormat is:


     HexFormat formatFingerprint = HexFormat.ofDelimiter(":").withUpperCase();
     byte[] bytes = {0, 1, 2, 3, 124, 125, 126, 127};
     String str = formatFingerprint.formatHex(bytes);
     byte[] parsed = formatFingerprint.parseHex(str);
     assert(Arrays.equals(bytes, parsed));

     // The formatted string is: "00:01:02:03:7C:7D:7E:7F"

This is a value-based class; use of identity-sensitive operations (including reference equality (==), identity hash code, or synchronization) on instances of HexFormat may have unpredictable results and should be avoided. The equals method should be used for comparisons.

This class is immutable and thread-safe.

Unless otherwise noted, passing a null argument to any method will cause a NullPointerException to be thrown.

Since:
17

method:of() [NONE]

  • of

    public static  HexFormat of()
    Returns a hexadecimal formatter with no delimiter and lowercase characters. The delimiter, prefix, and suffix are empty. The methods withDelimiter, withUpperCase, withLowerCase, withPrefix, and withSuffix return copies of formatters with new parameters.
    Returns:
    a hexadecimal formatter with no delimiter and lowercase characters

    • method:ofDelimiter(java.lang.String) [NONE]

    ofDelimiter

    public static  HexFormat ofDelimiter (String delimiter)
    Returns a hexadecimal formatter with the delimiter and lowercase characters. The prefix and suffix are empty. The methods withDelimiter, withUpperCase, withLowerCase, withPrefix, and withSuffix return copies of formatters with new parameters.
    Parameters:
    delimiter - a delimiter, non-null, may be empty
    Returns:
    a HexFormat with the delimiter and lowercase characters

    method:withDelimiter(java.lang.String) [NONE]

    withDelimiter

    public HexFormat withDelimiter (String delimiter)
    Returns a copy of this HexFormat with the delimiter.
    Parameters:
    delimiter - the delimiter, non-null, may be empty
    Returns:
    a copy of this HexFormat with the delimiter

    method:withPrefix(java.lang.String) [NONE]

    withPrefix

    public HexFormat withPrefix (String prefix)
    Returns a copy of this HexFormat with the prefix.
    Parameters:
    prefix - a prefix, non-null, may be empty
    Returns:
    a copy of this HexFormat with the prefix

    method:withSuffix(java.lang.String) [NONE]

    withSuffix

    public HexFormat withSuffix (String suffix)
    Returns a copy of this HexFormat with the suffix.
    Parameters:
    suffix - a suffix, non-null, may be empty
    Returns:
    a copy of this HexFormat with the suffix

    method:withUpperCase() [NONE]

    withUpperCase

    public HexFormat withUpperCase()
    Returns a copy of this HexFormat to use uppercase hexadecimal characters. The uppercase hexadecimal characters are "0-9", "A-F" .
    Returns:
    a copy of this HexFormat with uppercase hexadecimal characters

    method:withLowerCase() [NONE]

    withLowerCase

    public HexFormat withLowerCase()
    Returns a copy of this HexFormat to use lowercase hexadecimal characters. The lowercase hexadecimal characters are "0-9", "a-f" .
    Returns:
    a copy of this HexFormat with lowercase hexadecimal characters

    method:delimiter() [NONE]

    delimiter

    public String delimiter()
    Returns the delimiter between hexadecimal values in formatted hexadecimal strings.
    Returns:
    the delimiter, non-null, may be empty ""

    method:prefix() [NONE]

    prefix

    public String prefix()
    Returns the prefix used for each hexadecimal value in formatted hexadecimal strings.
    Returns:
    the prefix, non-null, may be empty ""

    method:suffix() [NONE]

    suffix

    public String suffix()
    Returns the suffix used for each hexadecimal value in formatted hexadecimal strings.
    Returns:
    the suffix, non-null, may be empty ""

    method:isUpperCase() [NONE]

    isUpperCase

    public boolean isUpperCase()
    Returns true if the hexadecimal digits are uppercase, otherwise false.
    Returns:
    true if the hexadecimal digits are uppercase, otherwise false

    method:formatHex(byte[]) [NONE]

    formatHex

    public String formatHex (byte[] bytes)
    Returns a hexadecimal string formatted from a byte array. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. The behavior is equivalent to formatHex(bytes, 0, bytes.length)) .
    Parameters:
    bytes - a non-null array of bytes
    Returns:
    a string hexadecimal formatting of the byte array

    method:formatHex(byte[],int,int) [NONE]

    formatHex

    public String formatHex (byte[] bytes, int fromIndex, int toIndex)
    Returns a hexadecimal string formatted from a byte array range. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last.
    Parameters:
    bytes - a non-null array of bytes
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive
    Returns:
    a string hexadecimal formatting each byte of the array range
    Throws:
    IndexOutOfBoundsException - if the array range is out of bounds

    method:formatHex(A,byte[]) [NONE]

    formatHex

    public <A extends Appendable>  A formatHex (A out, byte[] bytes)
    Appends formatted hexadecimal strings from a byte array to the Appendable. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. The formatted hexadecimal strings are appended in zero or more calls to the Appendable methods.
    Type Parameters:
    A - The type of Appendable
    Parameters:
    out - an Appendable, non-null
    bytes - a byte array
    Returns:
    the Appendable
    Throws:
    UncheckedIOException - if an I/O exception occurs appending to the output

    method:formatHex(A,byte[],int,int) [NONE]

    formatHex

    public <A extends Appendable>  A formatHex (A out, byte[] bytes, int fromIndex, int toIndex)
    Appends formatted hexadecimal strings from a byte array range to the Appendable. Each byte value is formatted as the prefix, two hexadecimal characters selected from uppercase or lowercase digits, and the suffix. A delimiter follows each formatted value, except the last. The formatted hexadecimal strings are appended in zero or more calls to the Appendable methods.
    Type Parameters:
    A - The type of Appendable
    Parameters:
    out - an Appendable, non-null
    bytes - a byte array, non-null
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive.
    Returns:
    the Appendable
    Throws:
    IndexOutOfBoundsException - if the array range is out of bounds
    UncheckedIOException - if an I/O exception occurs appending to the output

    method:parseHex(java.lang.CharSequence) [NONE]

    parseHex

    public byte[] parseHex (CharSequence string)
    Returns a byte array containing hexadecimal values parsed from the string. Each byte value is parsed from the prefix, two case insensitive hexadecimal characters, and the suffix. A delimiter follows each formatted value, except the last. The delimiters, prefixes, and suffixes strings must be present; they may be empty strings. A valid string consists only of the above format.
    Parameters:
    string - a string containing the byte values with prefix, hexadecimal digits, suffix, and delimiters
    Returns:
    a byte array with the values parsed from the string
    Throws:
    IllegalArgumentException - if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte value

    method:parseHex(java.lang.CharSequence,int,int) [NONE]

    parseHex

    public byte[] parseHex (CharSequence string, int fromIndex, int toIndex)
    Returns a byte array containing hexadecimal values parsed from a range of the string. Each byte value is parsed from the prefix, two case insensitive hexadecimal characters, and the suffix. A delimiter follows each formatted value, except the last. The delimiters, prefixes, and suffixes strings must be present; they may be empty strings. A valid string consists only of the above format.
    Parameters:
    string - a string range containing hexadecimal digits, delimiters, prefix, and suffix.
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive.
    Returns:
    a byte array with the values parsed from the string range
    Throws:
    IllegalArgumentException - if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte value
    IndexOutOfBoundsException - if the string range is out of bounds

    method:parseHex(char[],int,int) [NONE]

    parseHex

    public byte[] parseHex (char[] chars, int fromIndex, int toIndex)
    Returns a byte array containing hexadecimal values parsed from a range of the character array. Each byte value is parsed from the prefix, two case insensitive hexadecimal characters, and the suffix. A delimiter follows each formatted value, except the last. The delimiters, prefixes, and suffixes strings must be present; they may be empty strings. A valid character array range consists only of the above format.
    Parameters:
    chars - a character array range containing an even number of hexadecimal digits, delimiters, prefix, and suffix.
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive.
    Returns:
    a byte array with the values parsed from the character array range
    Throws:
    IllegalArgumentException - if the prefix or suffix is not present for each byte value, the byte values are not hexadecimal characters, or if the delimiter is not present after all but the last byte value
    IndexOutOfBoundsException - if the character array range is out of bounds

    method:toLowHexDigit(int) [NONE]

    toLowHexDigit

    public char toLowHexDigit (int value)
    Returns the hexadecimal character for the low 4 bits of the value considering it to be a byte. If the parameter isUpperCase() is true the character returned for values 10-15 is uppercase "A-F", otherwise the character returned is lowercase "a-f". The values in the range 0-9 are returned as "0-9".
    Parameters:
    value - a value, only the low 4 bits 0-3 of the value are used
    Returns:
    the hexadecimal character for the low 4 bits 0-3 of the value

    method:toHighHexDigit(int) [NONE]

    toHighHexDigit

    public char toHighHexDigit (int value)
    Returns the hexadecimal character for the high 4 bits of the value considering it to be a byte. If the parameter isUpperCase() is true the character returned for values 10-15 is uppercase "A-F", otherwise the character returned is lowercase "a-f". The values in the range 0-9 are returned as "0-9".
    Parameters:
    value - a value, only bits 4-7 of the value are used
    Returns:
    the hexadecimal character for the bits 4-7 of the value

    method:toHexDigits(A,byte) [NONE]

    toHexDigits

    public <A extends Appendable>  A toHexDigits (A out, byte value)
    Appends two hexadecimal characters for the byte value to the Appendable. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The hexadecimal characters are appended in one or more calls to the Appendable methods. The delimiter, prefix and suffix are not used.
    Type Parameters:
    A - The type of Appendable
    Parameters:
    out - an Appendable, non-null
    value - a byte value
    Returns:
    the Appendable
    Throws:
    UncheckedIOException - if an I/O exception occurs appending to the output

    method:toHexDigits(byte) [NONE]

    toHexDigits

    public String toHexDigits (byte value)
    Returns the two hexadecimal characters for the byte value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - a byte value
    Returns:
    the two hexadecimal characters for the byte value

    method:toHexDigits(char) [NONE]

    toHexDigits

    public String toHexDigits (char value)
    Returns the four hexadecimal characters for the char value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - a char value
    Returns:
    the four hexadecimal characters for the char value

    method:toHexDigits(short) [NONE]

    toHexDigits

    public String toHexDigits (short value)
    Returns the four hexadecimal characters for the short value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - a short value
    Returns:
    the four hexadecimal characters for the short value

    method:toHexDigits(int) [NONE]

    toHexDigits

    public String toHexDigits (int value)
    Returns the eight hexadecimal characters for the int value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - an int value
    Returns:
    the eight hexadecimal characters for the int value
    See Also:

    method:toHexDigits(long) [NONE]

    toHexDigits

    public String toHexDigits (long value)
    Returns the sixteen hexadecimal characters for the long value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - a long value
    Returns:
    the sixteen hexadecimal characters for the long value
    See Also:

    method:toHexDigits(long,int) [NONE]

    toHexDigits

    public String toHexDigits (long value, int digits)
    Returns up to sixteen hexadecimal characters for the long value. Each nibble (4 bits) from most significant to least significant of the value is formatted as if by toLowHexDigit(nibble). The delimiter, prefix and suffix are not used.
    Parameters:
    value - a long value
    digits - the number of hexadecimal digits to return, 0 to 16
    Returns:
    the hexadecimal characters for the long value
    Throws:
    IllegalArgumentException - if digits is negative or greater than 16

    method:isHexDigit(int) [NONE]

    isHexDigit

    public static  boolean isHexDigit (int ch)
    Returns true if the character is a valid hexadecimal character or codepoint. The valid hexadecimal characters are:
    • '0' ('\u0030') through '9' ('\u0039') inclusive,
    • 'A' ('\u0041') through 'F' ('\u0046') inclusive, and
    • 'a' ('\u0061') through 'f' ('\u0066') inclusive.
    Parameters:
    ch - a codepoint
    Returns:
    true if the character is valid a hexadecimal character, otherwise false

    method:fromHexDigit(int) [NONE]

    fromHexDigit

    public static  int fromHexDigit (int ch)
    Returns the value for the hexadecimal character or codepoint. The value is:
    • (ch - '0') for '0' through '9' inclusive,
    • (ch - 'A' + 10) for 'A' through 'F' inclusive, and
    • (ch - 'a' + 10) for 'a' through 'f' inclusive.
    Parameters:
    ch - a character or codepoint
    Returns:
    the value 0-15
    Throws:
    NumberFormatException - if the codepoint is not a hexadecimal character

    method:fromHexDigits(java.lang.CharSequence) [NONE]

    fromHexDigits

    public static  int fromHexDigits (CharSequence string)
    Returns the int value parsed from a string of up to eight hexadecimal characters. The hexadecimal characters are parsed from most significant to least significant using fromHexDigit(int) to form an unsigned value. The value is zero extended to 32 bits and is returned as an int.
    API Note:
    Integer.parseInt(s, 16) and Integer.parseUnsignedInt(s, 16) are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16) . HexFormat uses only hexadecimal characters "0-9", "A-F" and "a-f". Signed hexadecimal strings can be parsed with Integer.parseInt(String, int) .
    Parameters:
    string - a CharSequence containing up to eight hexadecimal characters
    Returns:
    the value parsed from the string
    Throws:
    IllegalArgumentException - if the string length is greater than eight (8) or if any of the characters is not a hexadecimal character

    method:fromHexDigits(java.lang.CharSequence,int,int) [NONE]

    fromHexDigits

    public static  int fromHexDigits (CharSequence string, int fromIndex, int toIndex)
    Returns the int value parsed from a string range of up to eight hexadecimal characters. The characters in the range fromIndex to toIndex, exclusive, are parsed from most significant to least significant using fromHexDigit(int) to form an unsigned value. The value is zero extended to 32 bits and is returned as an int.
    API Note:
    Integer.parseInt(s, 16) and Integer.parseUnsignedInt(s, 16) are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16) . HexFormat uses only hexadecimal characters "0-9", "A-F" and "a-f". Signed hexadecimal strings can be parsed with Integer.parseInt(String, int) .
    Parameters:
    string - a CharSequence containing the characters
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive.
    Returns:
    the value parsed from the string range
    Throws:
    IndexOutOfBoundsException - if the range is out of bounds for the CharSequence
    IllegalArgumentException - if length of the range is greater than eight (8) or if any of the characters is not a hexadecimal character

    method:fromHexDigitsToLong(java.lang.CharSequence) [NONE]

    fromHexDigitsToLong

    public static  long fromHexDigitsToLong (CharSequence string)
    Returns the long value parsed from a string of up to sixteen hexadecimal characters. The hexadecimal characters are parsed from most significant to least significant using fromHexDigit(int) to form an unsigned value. The value is zero extended to 64 bits and is returned as a long.
    API Note:
    Long.parseLong(s, 16) and Long.parseUnsignedLong(s, 16) are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16) . HexFormat uses only hexadecimal characters "0-9", "A-F" and "a-f". Signed hexadecimal strings can be parsed with Long.parseLong(String, int) .
    Parameters:
    string - a CharSequence containing up to sixteen hexadecimal characters
    Returns:
    the value parsed from the string
    Throws:
    IllegalArgumentException - if the string length is greater than sixteen (16) or if any of the characters is not a hexadecimal character

    method:fromHexDigitsToLong(java.lang.CharSequence,int,int) [NONE]

    fromHexDigitsToLong

    public static  long fromHexDigitsToLong (CharSequence string, int fromIndex, int toIndex)
    Returns the long value parsed from a string range of up to sixteen hexadecimal characters. The characters in the range fromIndex to toIndex, exclusive, are parsed from most significant to least significant using fromHexDigit(int) to form an unsigned value. The value is zero extended to 64 bits and is returned as a long.
    API Note:
    Long.parseLong(s, 16) and Long.parseUnsignedLong(s, 16) are similar but allow all Unicode hexadecimal digits defined by Character.digit(ch, 16) . HexFormat uses only hexadecimal characters "0-9", "A-F" and "a-f". Signed hexadecimal strings can be parsed with Long.parseLong(String, int) .
    Parameters:
    string - a CharSequence containing the characters
    fromIndex - the initial index of the range, inclusive
    toIndex - the final index of the range, exclusive.
    Returns:
    the value parsed from the string range
    Throws:
    IndexOutOfBoundsException - if the range is out of bounds for the CharSequence
    IllegalArgumentException - if the length of the range is greater than sixteen (16) or if any of the characters is not a hexadecimal character

    method:equals(java.lang.Object) [NONE]

    equals

    public boolean equals (Object o)
    Returns true if the other object is a HexFormat with the same parameters.
    Overrides:
    equals in class Object
    Parameters:
    o - an object, may be null
    Returns:
    true if the other object is a HexFormat and the parameters uppercase, delimiter, prefix, and suffix are equal; otherwise false
    See Also:

    method:hashCode() [NONE]

    hashCode

    public int hashCode()
    Returns a hashcode for this HexFormat.
    Overrides:
    hashCode in class Object
    Returns:
    a hashcode for this HexFormat
    See Also:

    method:toString() [NONE]

    toString

    public String toString()
    Returns a description of the formatter parameters for uppercase, delimiter, prefix, and suffix.
    Overrides:
    toString in class Object
    Returns:
    a description of this HexFormat

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