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Replaceable Class Reference

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. More...

#include <rep.h>

Inheritance diagram for Replaceable:

UnicodeString

Public Member Functions

virtual ~Replaceable ()
 Destructor.

int32_t length () const
 Return the number of characters in the text.

UChar charAt (int32_t offset) const
 Return the Unicode code unit at the given offset into the text.

UChar32 char32At (int32_t offset) const
 Return the Unicode code point that contains the code unit at the given offset into the text.

virtual void extractBetween (int32_t start, int32_t limit, UnicodeString &target) const =0
 Copy the characters in the range [start, limit) into the UnicodeString target.

virtual void handleReplaceBetween (int32_t start, int32_t limit, const UnicodeString &text)=0
 Replace a substring of this object with the given text.

virtual void copy (int32_t start, int32_t limit, int32_t dest)=0
 Copy a substring of this object, retaining attribute (out-of-band) information.


Protected Member Functions

 Replaceable ()
 Default constructor.

virtual int32_t getLength () const =0
 Virtual version of length().

virtual UChar getCharAt (int32_t offset) const =0
 Virtual version of charAt().

virtual UChar32 getChar32At (int32_t offset) const =0
 Virtual version of char32At().


Detailed Description

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 style attributes. In other words, an implicit aspect of the Replaceable API is that during a replace operation, new characters take on the attributes, if any, 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 <b>strong</b> font".

Replaceable specifies ranges using an initial offset and a limit offset. The range of characters thus specified includes the characters at offset initial..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(), and extractBetween().

If a subclass supports styles, then typically the behavior is the following:

If this is not the behavior, the subclass should document any differences.
Author:
Alan Liu


Constructor & Destructor Documentation

Replaceable::~Replaceable  )  [inline, virtual]
 

Destructor.


Member Function Documentation

UChar32 Replaceable::char32At int32_t  offset  )  const [inline]
 

Return the Unicode code point that contains the code unit at the given offset into the text.

Parameters:
offset an integer between 0 and length()-1 inclusive that indicates the text offset of any of the code units that will be assembled into a code point (21-bit value) and returned
Returns:
code point of text at given offset ICU 1.8

Reimplemented in UnicodeString.

UChar Replaceable::charAt int32_t  offset  )  const [inline]
 

Return the Unicode code unit at the given offset into the text.

Parameters:
offset an integer between 0 and length()-1 inclusive
Returns:
code unit of text at given offset ICU 1.8

Reimplemented in UnicodeString.

virtual void Replaceable::copy int32_t  start,
int32_t  limit,
int32_t  dest
[pure virtual]
 

Copy a substring of this object, retaining attribute (out-of-band) information.

This method is used to duplicate or reorder substrings. The destination index must not overlap the source range. Implementations that do not care about maintaining out-of-band information or performance during copying may use the naive implementation:

char[] text = new char[limit - start]; getChars(start, limit, text, 0); replace(dest, dest, text, 0, limit - start);

Parameters:
start the beginning index, inclusive; 0 <= start <= limit.
limit the ending index, exclusive; start <= limit <= length().
dest the destination index. The characters from start..limit-1 will be copied to dest. Implementations of this method may assume that dest <= start || dest >= limit.

Implemented in UnicodeString.

virtual void Replaceable::extractBetween int32_t  start,
int32_t  limit,
UnicodeString target
const [pure virtual]
 

Copy the characters in the range [start, limit) into the UnicodeString target.

Parameters:
start offset of first character which will be copied
limit offset immediately following the last character to be copied
target UnicodeString into which to copy characters.
Returns:
A reference to target ICU 2.1

Implemented in UnicodeString.

virtual void Replaceable::handleReplaceBetween int32_t  start,
int32_t  limit,
const UnicodeString text
[pure virtual]
 

Replace a substring of this object with the given text.

If the characters being replaced have attributes, the new characters that replace them should be given the same attributes.

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 out-of-band information such as styles should be unaffected. In addition, subclasses are encourage to check for initial and trailing identical characters, and make a smaller replacement if possible. This will preserve as much style information as possible.

Parameters:
start the beginning index, inclusive; 0 <= start <= limit.
limit the ending index, exclusive; start <= limit <= length().
text the text to replace characters start to limit - 1

Implemented in UnicodeString.

int32_t Replaceable::length  )  const [inline]
 

Return the number of characters in the text.

Returns:
number of characters in text ICU 1.8

Reimplemented in UnicodeString.


The documentation for this class was generated from the following file:
Generated on Sun Jan 18 22:55:44 2004 for ICU 2.1 by doxygen 1.3.4