RWUCollationKey Class Reference
[Unicode String Processing]

Stores preprocessed comparison information for a Unicode string to speed repeated string comparisons. More...

#include <rw/i18n/RWUCollationKey.h>

List of all members.

Public Member Functions
	RWUCollationKey (void)
	RWUCollationKey (const RWUCollationKey &original)
RWUCollationKey &	operator= (const RWUCollationKey &rhs)
	~RWUCollationKey (void)
bool	isValid (void) const
bool	operator== (const RWUCollationKey &rhs) const
bool	operator!= (const RWUCollationKey &rhs) const
bool	operator< (const RWUCollationKey &rhs) const
unsigned	hash () const
RWUString	getString (void) const

---

Detailed Description

RWUCollationKey stores preprocessed comparison information for a Unicode string, and can be used to speed repeated string comparisons. For example, you might choose to use collation keys when sorting a set of strings.

To create a valid RWUCollationKey, call RWUCollator::getCollationKey(). Generating a key is a non-trivial operation, since it involves determining the collation elements and weights for an entire string. Comparing two RWUCollationKey objects, however, is fast.

Note:

Collation keys can only meaningfully be compared if they are created by the same collator, or by collators with the same attributes.

Examples

 #include <rw/i18n/RWUCollationKey.h>
 #include <rw/i18n/RWUCollator.h>
 #include <rw/i18n/RWUConversionContext.h>
 #include <rw/tvsrtvec.h>
 #include <iostream>
 
 using std::cout;
 using std::endl;
 
 int
 main()
 {
   // Indicate that source and target strings are
   // encoded as UTF-8.
   RWUConversionContext context("UTF-8");
 
   // Create an array of country names.
   RWUString array[] = {
     "United States",
     "Netherlands",
     "United Kingdom",
     "Germany",
     "France",
     "Italy",
     "Japan",
     "Australia",
     ""
   };
   size_t max_array_length = 20;
 
   // Create a collator based on the "en" locale.
   RWUCollator collator("en");
   
   // Create an empty vector.  An RWTValSortedVector<T>
   // will automatically keep its contents in sorted
   // order.
   RWTValSortedVector<RWUCollationKey,
                      std::less<RWUCollationKey> > vector(max_array_length);
   // Populate the vector with RWUCollationKey objects.
   // Note that the vector will use
   // RWUCollationKey::operator<() and operator==().
   size_t i;
   for (i = 0; array[i].isNull() == false; ++i) {
     vector.insert(collator.getCollationKey(array[i]));
   } // for
 
   // Print the sorted vector.  Obtain RWUString objects
   // from the stored RWUCollationKey objects, implicitly
   // convert them to UTF-8, and print the UTF-8.
   cout << "Rogue Wave has offices in the following "
    "countries:" << endl;
   for (i = 0; i < vector.entries(); ++i) {
     cout << "  " << vector[i].getString() << endl;
   } // for
 
   return 0;
 } // main

Program output:

 Rogue Wave has offices in the following countries:
   Australia
   France
   Germany
   Italy
   Japan
   Netherlands
   United Kingdom
   United States

See also:

RWUCollator

---

Constructor & Destructor Documentation

RWUCollationKey::RWUCollationKey

(

void

)

[inline]

Default constructor. Creates an invalid key.

Invalid keys are equal to each other, and not equal to any other key. They are less than all other keys. Calling getString() on an invalid key results in an RWUException.

This constructor exists only as a convenience--for example, when creating an array of RWUCollationKey objects. To create a valid, usable RWUCollationKey, call RWUCollator::getCollationKey().

RWUCollationKey::RWUCollationKey

(

const RWUCollationKey &

original

)

Copy constructor. Makes self a deep copy of original.

RWUCollationKey::~RWUCollationKey

(

void

)

[inline]

Destructor.

---

Member Function Documentation

RWUString RWUCollationKey::getString

(

void

)

const

Returns the string whose collation value self holds. Throws RWUException if self is an invalid key.

unsigned RWUCollationKey::hash

(

)

const [inline]

Returns a hash value for self.

bool RWUCollationKey::isValid

(

void

)

const [inline]

Returns true if self is a valid key; otherwise, false.

bool RWUCollationKey::operator!=

(

const RWUCollationKey &

rhs

)

const

Returns true if self does not compare equal to collation key rhs; otherwise false.

Note:

collation keys can only meaningfully be compared if they are created by the same collator, or by collators with the same attributes.

bool RWUCollationKey::operator<

(

const RWUCollationKey &

rhs

)

const

Returns true if self compares less than collation key rhs; otherwise false.

Note:

collation keys can only meaningfully be compared if they are created by the same collator, or by collators with the same attributes.

RWUCollationKey& RWUCollationKey::operator=

(

const RWUCollationKey &

rhs

)

Assignment operator. Makes self a deep copy of rhs.

bool RWUCollationKey::operator==

(

const RWUCollationKey &

rhs

)

const

Returns true if self compares equal to collation key rhs; otherwise false.

Note:

collation keys can only meaningfully be compared if they are created by the same collator, or by collators with the same attributes.