Package org.python.core.stringlib

Class InternalFormat.Spec

java.lang.Object
org.python.core.stringlib.InternalFormat.Spec
Enclosing class:
InternalFormat
public static class InternalFormat.Spec extends Object
Parsed PEP-3101 format specification of a single field, encapsulating the format for use by formatting methods. This class holds the several attributes that might be decoded from a format specifier. Each attribute has a reserved value used to indicate "unspecified". Spec objects may be merged such that one Spec provides values, during the construction of a new Spec, for attributes that are unspecified in a primary source.

This structure is returned by factory method InternalFormat.fromText(String), and having public final members is freely accessed by formatters such as FloatFormatter, and the __format__ methods of client object types.

The fields correspond to the elements of a format specification. The grammar of a format specification is: 

 [[fill]align][sign][#][0][width][,][.precision][type]
A typical idiom is: 
     private static final InternalFormatSpec FLOAT_DEFAULTS = InternalFormatSpec.from(">");
     ...
         InternalFormat.Spec spec = InternalFormat.fromText(specString);
         spec = spec.withDefaults(FLOAT_DEFAULTS);
         ... // Validation of spec.type, and other attributes, for this type.
         FloatFormatter f = new FloatFormatter(spec);
         String result = f.format(value).getResult();

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    final char
    align
    Alignment indicator is one of {'<', '^', '>', '=', or U+FFFF if unspecified.
    final boolean
    alternate
    The alternative format flag '#' was given.
    final char
    fill
    The fill character specified, or U+FFFF if unspecified.
    final boolean
    grouping
    Insert the grouping separator (which in Python always indicates a group-size of 3).
    static final char
    NONE
    Non-character code point used to represent "no value" in char attributes.
    static final InternalFormat.Spec
    NUMERIC
    Defaults applicable to most numeric types.
    final int
    precision
    Precision decoded from the format, or -1 if unspecified.
    final char
    sign
    Sign-handling flag, one of '+', '-', or ' ', or U+FFFF if unspecified.
    static final InternalFormat.Spec
    STRING
    Defaults applicable to string types.
    final char
    type
    Type key from the format, or U+FFFF if unspecified.
    static final int
    UNSPECIFIED
    Negative value used to represent "no value" in int attributes.
    final int
    width
    Width to which to pad the result, or -1 if unspecified.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Spec(char fill, char align, char sign, boolean alternate, int width, boolean grouping, int precision, char type)
    Constructor to set all the fields in the format specifier.
    Spec(int precision, char type)
    Constructor offering just precision and type.

  • Method Summary

    Modifier and Type
    Method
    Description
    char
    getAlign(char defaultAlign)
    The alignment from the parsed format specification, or default.
    char
    getFill(char defaultFill)
    The alignment from the parsed format specification, or default.
    int
    getPrecision(int defaultPrecision)
    The precision from the parsed format specification, or default.
    char
    getType(char defaultType)
    The type code from the parsed format specification, or default supplied.
    static final boolean
    specified(char c)
    Test to see if an attribute has been specified.
    static final boolean
    specified(int value)
    Test to see if an attribute has been specified.
    String
    toString()
    Return a format specifier (text) equivalent to the value of this Spec.
    InternalFormat.Spec
    withDefaults(InternalFormat.Spec other)
    Return a merged Spec object, in which any attribute of this object that is specified (or true), has the same value in the result, and any attribute of this object that is unspecified (or false), has the value that attribute takes in the other object.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

    • fill

      public final char fill
      The fill character specified, or U+FFFF if unspecified.

    • align

      public final char align
      Alignment indicator is one of {'<', '^', '>', '=', or U+FFFF if unspecified.

    • sign

      public final char sign
      Sign-handling flag, one of '+', '-', or ' ', or U+FFFF if unspecified.

    • alternate

      public final boolean alternate
      The alternative format flag '#' was given.

    • width

      public final int width
      Width to which to pad the result, or -1 if unspecified.

    • grouping

      public final boolean grouping
      Insert the grouping separator (which in Python always indicates a group-size of 3).

    • precision

      public final int precision
      Precision decoded from the format, or -1 if unspecified.

    • type

      public final char type
      Type key from the format, or U+FFFF if unspecified.

    • NONE

      public static final char NONE
      Non-character code point used to represent "no value" in char attributes.
      See Also:

    • UNSPECIFIED

      public static final int UNSPECIFIED
      Negative value used to represent "no value" in int attributes.
      See Also:

    • NUMERIC

      public static final InternalFormat.Spec NUMERIC
      Defaults applicable to most numeric types. Equivalent to " >"

    • STRING

      public static final InternalFormat.Spec STRING
      Defaults applicable to string types. Equivalent to " <"

  • Constructor Details

    • Spec

      public Spec(char fill, char align, char sign, boolean alternate, int width, boolean grouping, int precision, char type)
      Constructor to set all the fields in the format specifier. 
       [[fill]align][sign][#][0][width][,][.precision][type]
      Parameters:
      fill - fill character (or NONE
      align - alignment indicator, one of {'<', '^', '>', '='}
      sign - policy, one of '+', '-', or ' '.
      alternate - true to request alternate formatting mode ('#' flag).
      width - of field after padding or -1 to default
      grouping - true to request comma-separated groups
      precision - (e.g. decimal places) or -1 to default
      type - indicator character

    • Spec

      public Spec(int precision, char type)
      Constructor offering just precision and type. 
       [.precision][type]
      Parameters:
      precision - (e.g. decimal places)
      type - indicator character

  • Method Details

    • specified

      public static final boolean specified(char c)
      Test to see if an attribute has been specified.
      Parameters:
      c - attribute
      Returns:
      true only if the attribute is not equal to NONE

    • specified

      public static final boolean specified(int value)
      Test to see if an attribute has been specified.
      Parameters:
      value - of attribute
      Returns:
      true only if the attribute is ≥0 (meaning that it has been specified).

    • toString

      public String toString()
      Return a format specifier (text) equivalent to the value of this Spec.
      Overrides:
      toString in class Object

    • withDefaults

      public InternalFormat.Spec withDefaults(InternalFormat.Spec other)
      Return a merged Spec object, in which any attribute of this object that is specified (or true), has the same value in the result, and any attribute of this object that is unspecified (or false), has the value that attribute takes in the other object. Thus the second object supplies default values. (These defaults may also be unspecified.) The use of this method is to allow a Spec constructed from text to record exactly, and only, what was in the textual specification, while the __format__ method of a client object supplies its type-specific defaults. Thus "20" means "<20s" to a str, ">20.12" to a float and ">20.12g" to a complex.
      Parameters:
      other - defaults to merge where this object does not specify the attribute.
      Returns:
      a new Spec object.

    • getFill

      public char getFill(char defaultFill)
      The alignment from the parsed format specification, or default.

    • getAlign

      public char getAlign(char defaultAlign)
      The alignment from the parsed format specification, or default.

    • getPrecision

      public int getPrecision(int defaultPrecision)
      The precision from the parsed format specification, or default.

    • getType

      public char getType(char defaultType)
      The type code from the parsed format specification, or default supplied.