Public Member Functions
|virtual ||~Replaceable ()|
| ||Destructor. |
|int32_t ||length () const |
| ||Returns the number of 16-bit code units in the text. |
|UChar ||charAt (int32_t offset) const |
| ||Returns the 16-bit code unit at the given offset into the text. |
|UChar32 ||char32At (int32_t offset) const |
| ||Returns the 32-bit code point at the given 16-bit offset into the text. |
|virtual void ||extractBetween (int32_t start, int32_t limit, UnicodeString &target) const =0|
| ||Copies characters in the range [|
limit) into the UnicodeString
|virtual void ||handleReplaceBetween (int32_t start, int32_t limit, const UnicodeString &text)=0|
| ||Replaces a substring of this object with the given text. |
|virtual void ||copy (int32_t start, int32_t limit, int32_t dest)=0|
| ||Copies a substring of this object, retaining metadata. |
|virtual UBool ||hasMetaData () const |
| ||Returns true if this object contains metadata. |
|virtual Replaceable * ||clone () const |
| ||Clone this object, an instance of a subclass of Replaceable. |
|virtual ||~UObject ()|
| ||Destructor. |
|virtual UClassID ||getDynamicClassID () const |
| ||ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class. |
Replaceable is an abstract base class 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 <b>bold</b>
font" has range (4, 8) replaced with "strong", then it becomes "the
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:
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.
- Alan Liu
- ICU 2.0
Definition at line 71 of file rep.h.
|virtual void icu::Replaceable::handleReplaceBetween
||const UnicodeString &
Replaces a substring of this object with the given text.
If the characters being replaced have metadata, the new characters that replace them should be given the same metadata.
Subclasses must ensure that if the text between start and limit is equal to the replacement text, that replace has no effect. That is, any metadata should be unaffected. In addition, subclasses are encouraged to check for initial and trailing identical characters, and make a smaller replacement if possible. This will preserve as much metadata as possible.
|start||the beginning index, inclusive; |
0 <= start <= limit.
|limit||the ending index, exclusive; |
start <= limit <= length().
|text||the text to replace characters |
limit - 1
- ICU 2.0
Implemented in icu::UnicodeString.