jdk.text.CollationKey
A CollationKey represents a String under the rules of a specific Collator object. Comparing two CollationKeys returns the relative order of the Strings they represent. Using CollationKeys to compare Strings is generally faster than using Collator.compare. Thus, when the Strings must be compared multiple times, for example when sorting a list of Strings. It's more efficient to use CollationKeys.
You can not create CollationKeys directly. Rather, generate them by calling Collator.getCollationKey. You can only compare CollationKeys generated from the same Collator object.
Generating a CollationKey for a String involves examining the entire String and converting it to series of bits that can be compared bitwise. This allows fast comparisons once the keys are generated. The cost of generating keys is recouped in faster comparisons when Strings need to be compared many times. On the other hand, the result of a comparison is often determined by the first couple of characters of each String. Collator.compare examines only as many characters as it needs which allows it to be faster when doing single comparisons.
The following example shows how CollationKeys might be used to sort a list of Strings.
// Create an array of CollationKeys for the Strings to be sorted. Collator myCollator = Collator.getInstance(); CollationKey[] keys = new CollationKey[3]; keys[0] = myCollator.getCollationKey("Tom"); keys[1] = myCollator.getCollationKey("Dick"); keys[2] = myCollator.getCollationKey("Harry"); sort(keys);
//...
// Inside body of sort routine, compare keys this way if (keys[i].compareTo(keys[j]) > 0) // swap keys[i] and keys[j]
//...
// Finally, when we've returned from sort. System.out.println(keys[0].getSourceString()); System.out.println(keys[1].getSourceString()); System.out.println(keys[2].getSourceString());
A CollationKey represents a String under the
rules of a specific Collator object. Comparing two
CollationKeys returns the relative order of the
Strings they represent. Using CollationKeys
to compare Strings is generally faster than using
Collator.compare. Thus, when the Strings
must be compared multiple times, for example when sorting a list
of Strings. It's more efficient to use CollationKeys.
You can not create CollationKeys directly. Rather,
generate them by calling Collator.getCollationKey.
You can only compare CollationKeys generated from
the same Collator object.
Generating a CollationKey for a String
involves examining the entire String
and converting it to series of bits that can be compared bitwise. This
allows fast comparisons once the keys are generated. The cost of generating
keys is recouped in faster comparisons when Strings need
to be compared many times. On the other hand, the result of a comparison
is often determined by the first couple of characters of each String.
Collator.compare examines only as many characters as it needs which
allows it to be faster when doing single comparisons.
The following example shows how CollationKeys might be used
to sort a list of Strings.
// Create an array of CollationKeys for the Strings to be sorted.
Collator myCollator = Collator.getInstance();
CollationKey[] keys = new CollationKey[3];
keys[0] = myCollator.getCollationKey("Tom");
keys[1] = myCollator.getCollationKey("Dick");
keys[2] = myCollator.getCollationKey("Harry");
sort(keys);
//...
// Inside body of sort routine, compare keys this way
if (keys[i].compareTo(keys[j]) > 0)
// swap keys[i] and keys[j]
//...
// Finally, when we've returned from sort.
System.out.println(keys[0].getSourceString());
System.out.println(keys[1].getSourceString());
System.out.println(keys[2].getSourceString());compare-toclj
(compare-to this target)Compare this CollationKey to the target CollationKey. The collation rules of the Collator object which created these keys are applied. Note: CollationKeys created by different Collators can not be compared.
target - target CollationKey - java.text.CollationKey
returns: Returns an integer value. Value is less than zero if this is less
than target, value is zero if this and target are equal and value is greater than
zero if this is greater than target. - int
Compare this CollationKey to the target CollationKey. The collation rules of the Collator object which created these keys are applied. Note: CollationKeys created by different Collators can not be compared. target - target CollationKey - `java.text.CollationKey` returns: Returns an integer value. Value is less than zero if this is less than target, value is zero if this and target are equal and value is greater than zero if this is greater than target. - `int`
get-source-stringclj
(get-source-string this)Returns the String that this CollationKey represents.
returns: the source string of this CollationKey - java.lang.String
Returns the String that this CollationKey represents. returns: the source string of this CollationKey - `java.lang.String`
to-byte-arrayclj
(to-byte-array this)Converts the CollationKey to a sequence of bits. If two CollationKeys could be legitimately compared, then one could compare the byte arrays for each of those keys to obtain the same result. Byte arrays are organized most significant byte first.
returns: a byte array representation of the CollationKey - byte[]
Converts the CollationKey to a sequence of bits. If two CollationKeys could be legitimately compared, then one could compare the byte arrays for each of those keys to obtain the same result. Byte arrays are organized most significant byte first. returns: a byte array representation of the CollationKey - `byte[]`
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