For example (with strength == tertiary) *
When comparing "Abernathy" to "Baggins-Smythworthy", Collator * only needs to process a couple of characters, while a comparison * with CollationKeys will process all of the characters. On the other hand, * if you are doing a sort of a number of fields, it is much faster to use * CollationKeys, since you will be comparing strings multiple times. *
Typical use of CollationKeys are in databases, where you store a CollationKey * in a hidden field, and use it for sorting or indexing. * *
Example of use: *
* . ErrorCode status = ZERO_ERROR;
* . Collator *myCollation = Collator::getDefault(Locale::FRANCE, status);
* . if (FAILURE(status)) return;
* . // Set to ignore the accent differences
* . myCollation->setStrength(Collator::PRIMARY);
* . UniChar sortchars[][MAX_TOKEN] = {
* . {'a', 'b', 'c', 0},
* . {0x00e4, 'b', 'c', 0},
* . {0x00c4, 'B', 'C', 0},
* . {0x00c4, 'b', 'c', 0},
* . {'r', 'e', 's', 'u', 'm', 'e', 0},
* . {'r', 0x00e9, 's', 'u', 'm', 0x00e9, 0},
* . {'R', 'E', 'S', 'U', 'M', 'E', 0},
* . {'R', 0x00e9, 's', 'u', 'm', 0x00e9, 0}
* . };
* . UnicodeString *sortlist[8];
* . CollationKey sortKeys[8];
* . myCollation->setStrength(Collator::SECONDARY);
* . int i;
* . for (i = 0; i < 8; i++) {
* . ErrorCode keyStatus = ZERO_ERROR;
* . sortlist[i] = new UnicodeString(sortchars[i]);
* . sortKeys[i] = myCollation->getCollationKey(*sortlist[i], sortKeys[i], keyStatus);
* . if (FAILURE(keyStatus)) { delete myCollation; return; } // getCollationKey failed.
* . }
* . // query the "RESUME", "résumé", and "Résumé" collation keys
* . // will return the objects that compares equal
* . if ((sortKeys[4] == sortKeys[5]) &&
* . (sortKeys[5] == sortKeys[6]) &&
* . (sortKeys[6] == sortKey2[7]))
* . printf("Test passes!\n");
*
* Because Collator::compare()'s algorithm is complex, it is faster to sort * long lists of words by retrieving collation keys with Collator::getCollationKey(). * You can then cache the collation keys and compare them using CollationKey::compareTo(). * @see Collator * @see RuleBasedCollator * @version 1.3 12/18/96 * @author Helena Shih */ #ifdef NLS_MAC #pragma export on #endif class T_COLLATE_API CollationKey { public : /** * This creates an empty collation key based on the null string. An empty * collation key contains no sorting information. When comparing two empty * collation keys, the result is Collator::EQUAL. Comparing empty collation key * with non-empty collation key is always Collator::LESS. */ CollationKey(); /** * Creates a collation key based on the collation key values. * @param values the collation key values * @param count number of collation key values * @see #createBits */ CollationKey(const t_uint8* values, t_int32 count); /** * Copy constructor. */ CollationKey(const CollationKey& other); /** * Sort key destructor. */ ~CollationKey(); /** * Assignment operator */ const CollationKey& operator=(const CollationKey& other); /** * Compare if two collation keys are the same. * @param source the collation key to compare to. * @return Returns true if two collation keys are equal, false otherwise. */ t_bool operator==(const CollationKey& source) const; /** * Compare if two collation keys are not the same. * @param source the collation key to compare to. * @return Returns true if two collation keys are different, false otherwise. */ t_bool operator!=(const CollationKey& source) const; /** * Extracts the collation key values. * @param count the output parameter of number of collation key values */ t_uint8* toByteArray( t_int32& count) const; t_uint8* createBits( t_int32& count) const; /** * Convenience method which does a string(bit-wise) comparison of the * two collation keys. * @param sourceKey source collation key * @param targetKey target collation key * @return Returns Collator::LESS if sourceKey < targetKey, * Collator::GREATER if sourceKey > targetKey and Collator::EQUAL * otherwise. * @see UnicodeString::compare */ Collator::EComparisonResult compareTo(const CollationKey& target) const; Collator::EComparisonResult compare(const CollationKey& target) const; /** * Creates an integer that is unique to the collation key. NOTE: this * is not the same as String.hashCode. *
Example of use: *
* . ErrorCode status = ZERO_ERROR;
* . Collator *myCollation = Collator::createInstance(Locale::US, status);
* . if (FAILURE(status)) return;
* . CollationKey key1, key2;
* . ErrorCode status1 = ZERO_ERROR, status2 = ZERO_ERROR;
* . myCollation->getCollationKey("abc", key1, status1);
* . if (FAILURE(status1)) { delete myCollation; return; }
* . myCollation->getCollationKey("ABC", key2, status2);
* . if (FAILURE(status2)) { delete myCollation; return; }
* . // key1.hashCode() != key2.hashCode()
*
* @return the hash value based on the string's collation order.
* @see UnicodeString#hashCode
*/
t_int32 hashCode() const;
const UniChar* getValues(t_int32& size) const;
private:
/*
* Creates a collation key with a string.
*/
CollationKey(const UnicodeString& value);
friend class RuleBasedCollator;
UnicodeString strValue;
};
#ifdef NLS_MAC
#pragma export off
#endif
inline const CollationKey&
CollationKey::operator=( const CollationKey& other)
{
if (this != &other) {
strValue = other.strValue;
}
return *this;
}
inline t_bool
CollationKey::operator==(const CollationKey& source) const
{
return (this->strValue == source.strValue);
}
inline t_bool
CollationKey::operator!=( const CollationKey& other) const
{
return !(*this == other);
}
inline t_int32
CollationKey::hashCode() const
{
return (strValue.hashCode());
}
// Bitwise comparison for the collation keys.
inline Collator::EComparisonResult
CollationKey::compareTo(const CollationKey& target) const
{
return (Collator::EComparisonResult)strValue.compare(target.strValue);
}
inline Collator::EComparisonResult
CollationKey::compare(const CollationKey& target) const
{
return compareTo(target);
}
inline t_uint8*
CollationKey::createBits( t_int32& count) const
{
return toByteArray(count);
}
inline const UniChar*
CollationKey::getValues(t_int32& size) const
{
size = strValue.size();
return ((const UniChar*)strValue);
}
#endif