public interface

Replaceable

sun.text.normalizer.Replaceable
Known Indirect Subclasses

Class Overview

Replaceable is an interface representing a string of characters that supports the replacement of a range of itself with a new string of characters. It is used by APIs that change a piece of text while retaining metadata. Metadata is data other than the Unicode characters returned by char32At(). One example of metadata is style attributes; another is an edit history, marking each character with an author and revision number.

An implicit aspect of the Replaceable API is that during a replace operation, new characters take on the metadata of the old characters. For example, if the string "the bold font" has range (4, 8) replaced with "strong", then it becomes "the strong font".

Replaceable specifies ranges using a start offset and a limit offset. The range of characters thus specified includes the characters at offset start..limit-1. That is, the start offset is inclusive, and the limit offset is exclusive.

Replaceable also includes API to access characters in the string: length(), charAt(), char32At(), and extractBetween().

For a subclass to support metadata, typical behavior of replace() is the following:

  • Set the metadata of the new text to the metadata of the first character replaced
  • If no characters are replaced, use the metadata of the previous character
  • If there is no previous character (i.e. start == 0), use the following character
  • If there is no following character (i.e. the replaceable was empty), use default metadata
  • If the code point U+FFFF is seen, it should be interpreted as a special marker having no metadata
If this is not the behavior, the subclass should document any differences.

Copyright © IBM Corporation 1999. All rights reserved.

Summary

Public Methods
abstract char charAt(int offset)
Returns the 16-bit code unit at the given offset into the text.
abstract void getChars(int srcStart, int srcLimit, char[] dst, int dstStart)
Copies characters from this object into the destination character array.
abstract int length()
Returns the number of 16-bit code units in the text.

Public Methods

public abstract char charAt (int offset)

Returns the 16-bit code unit at the given offset into the text.

Parameters
offset an integer between 0 and length()-1 inclusive
Returns
  • 16-bit code unit of text at given offset

public abstract void getChars (int srcStart, int srcLimit, char[] dst, int dstStart)

Copies characters from this object into the destination character array. The first character to be copied is at index srcStart; the last character to be copied is at index srcLimit-1 (thus the total number of characters to be copied is srcLimit-srcStart). The characters are copied into the subarray of dst starting at index dstStart and ending at index dstStart + (srcLimit-srcStart) - 1.

Parameters
srcStart the beginning index to copy, inclusive; 0 <= start <= limit.
srcLimit the ending index to copy, exclusive; start <= limit <= length().
dst the destination array.
dstStart the start offset in the destination array.

public abstract int length ()

Returns the number of 16-bit code units in the text.

Returns
  • number of 16-bit code units in text