Main Page   Class Hierarchy   Alphabetical List   Data Structures   File List   Data Fields   Globals  

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 Methods

virtual ~Replaceable ()
 Destructor. More...

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

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

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

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

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

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. More...


Protected Methods

 Replaceable ()
 Default constructor.

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

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

virtual UChar32 getChar32At (UTextOffset 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 bold font" has range (4, 8) replaced with "strong", then it becomes "the strong 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 @stable


Constructor & Destructor Documentation

Replaceable::~Replaceable   [inline, virtual]
 

Destructor.

@stable


Member Function Documentation

UChar32 Replaceable::char32At UTextOffset    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 @draft ICU 1.8

Reimplemented in UnicodeString.

UChar Replaceable::charAt UTextOffset    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 @draft 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. @stable

Implemented in UnicodeString.

virtual void Replaceable::extractBetween UTextOffset    start,
UTextOffset    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 @draft ICU 2.1

Implemented in UnicodeString.

virtual void Replaceable::handleReplaceBetween UTextOffset    start,
UTextOffset    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 @stable

Implemented in UnicodeString.

int32_t Replaceable::length   const [inline]
 

Return the number of characters in the text.

Returns:
number of characters in text @draft ICU 1.8

Reimplemented in UnicodeString.


The documentation for this class was generated from the following file:
Generated on Sun Mar 10 02:54:33 2002 for ICU 2.0 by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002