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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::

UObject UMemory UnicodeString List of all members.

Public Methods

virtual ~Replaceable ()
 Destructor. More...

int32_t length () const
 Returns the number of 16-bit code units in the text. More...

UChar charAt (int32_t offset) const
 Returns the 16-bit code unit at the given offset into the text. More...

UChar32 char32At (int32_t offset) const
 Returns the 32-bit code point at the given 16-bit offset into the text. More...

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

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

virtual void copy (int32_t start, int32_t limit, int32_t dest)=0
 Copies a substring of this object, retaining metadata. More...

virtual UBool hasMetaData () const
 Returns true if this object contains metadata. More...

virtual Replaceable * clone () const
 Clone this object, an instance of a subclass of Replaceable. More...


Protected Methods

 Replaceable ()
 Default constructor. More...

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

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

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


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 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:

If this is not the behavior, the subclass should document any differences.
Author:
Alan Liu
Stable:
ICU 2.0

Definition at line 66 of file rep.h.


Constructor & Destructor Documentation

virtual Replaceable::~Replaceable   [virtual]
 

Destructor.

Stable:
ICU 2.0

Replaceable::Replaceable   [inline, protected]
 

Default constructor.

Draft:
This API has been introduced in ICU 2.4. It is still in draft state and may be modified in a future release.

Definition at line 235 of file rep.h.


Member Function Documentation

UChar32 Replaceable::char32At int32_t    offset const [inline]
 

Returns the 32-bit code point at the given 16-bit offset into the text.

This assumes the text is stored as 16-bit code units with surrogate pairs intermixed. If the offset of a leading or trailing code unit of a surrogate pair is given, return the code point of the surrogate pair.

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

Reimplemented in UnicodeString.

Definition at line 248 of file rep.h.

UChar Replaceable::charAt int32_t    offset const [inline]
 

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
Stable:
ICU 1.8

Reimplemented in UnicodeString.

Definition at line 243 of file rep.h.

virtual Replaceable* Replaceable::clone void    const [virtual]
 

Clone this object, an instance of a subclass of Replaceable.

Clones can be used concurrently in multiple threads. If a subclass does not implement clone(), or if an error occurs, then NULL is returned. The clone functions in all subclasses return a pointer to a Replaceable because some compilers do not support covariant (same-as-this) return types; cast to the appropriate subclass if necessary. The caller must delete the clone.

Returns:
a clone of this object
See also:
getDynamicClassID
Draft:
This API has been introduced in ICU 2.6. It is still in draft state and may be modified in a future release.

Reimplemented in UnicodeString.

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

Copies a substring of this object, retaining metadata.

This method is used to duplicate or reorder substrings. The destination index must not overlap the source range.

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:
ICU 2.0

Reimplemented in UnicodeString.

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

Copies 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
Stable:
ICU 2.1

Reimplemented in UnicodeString.

virtual UChar32 Replaceable::getChar32At int32_t    offset const [protected, pure virtual]
 

Virtual version of char32At().

Draft:
This API has been introduced in ICU 2.4. It is still in draft state and may be modified in a future release.

Reimplemented in UnicodeString.

Referenced by char32At().

virtual UChar Replaceable::getCharAt int32_t    offset const [protected, pure virtual]
 

Virtual version of charAt().

Draft:
This API has been introduced in ICU 2.4. It is still in draft state and may be modified in a future release.

Reimplemented in UnicodeString.

Referenced by charAt().

virtual int32_t Replaceable::getLength void    const [protected, pure virtual]
 

Virtual version of length().

Draft:
This API has been introduced in ICU 2.4. It is still in draft state and may be modified in a future release.

Reimplemented in UnicodeString.

Referenced by length().

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

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.

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:
ICU 2.0

Reimplemented in UnicodeString.

virtual UBool Replaceable::hasMetaData   const [virtual]
 

Returns true if this object contains metadata.

If a Replaceable object has metadata, calls to the Replaceable API must be made so as to preserve metadata. If it does not, calls to the Replaceable API may be optimized to improve performance. The default implementation returns true.

Returns:
true if this object contains metadata
Stable:
ICU 2.2

Reimplemented in UnicodeString.

int32_t Replaceable::length void    const [inline]
 

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

Returns:
number of 16-bit code units in text
Stable:
ICU 1.8

Reimplemented in UnicodeString.

Definition at line 238 of file rep.h.


The documentation for this class was generated from the following file:
Generated on Mon Nov 24 14:36:45 2003 for ICU 2.8 by doxygen1.2.11.1 written by Dimitri van Heesch, © 1997-2001