| java.lang.Object
 java.text.CollationElementIterator
| CollationElementIterator | | final public class CollationElementIterator (Code) | | The CollationElementIterator class is used as an iterator
to walk through each character of an international string. Use the iterator
to return the ordering priority of the positioned character. The ordering
priority of a character, which we refer to as a key, defines how a character
is collated in the given collation object.
For example, consider the following in Spanish:
"ca" -> the first key is key('c') and second key is key('a').
"cha" -> the first key is key('ch') and second key is key('a').
And in German,
"\u00e4b"-> the first key is key('a'), the second key is key('e'), and
the third key is key('b').
The key of a character is an integer composed of primary order(short),
secondary order(byte), and tertiary order(byte). Java strictly defines
the size and signedness of its primitive data types. Therefore, the static
functions primaryOrder, secondaryOrder, and
tertiaryOrder return int, short,
and short respectively to ensure the correctness of the key
value.
Example of the iterator usage,
String testString = "This is a test";
RuleBasedCollator ruleBasedCollator = (RuleBasedCollator)Collator.getInstance();
CollationElementIterator collationElementIterator = ruleBasedCollator.getCollationElementIterator(testString);
int primaryOrder = CollationElementIterator.primaryOrder(collationElementIterator.next());
CollationElementIterator.next returns the collation order
of the next character. A collation order consists of primary order,
secondary order and tertiary order. The data type of the collation
order is int. The first 16 bits of a collation order
is its primary order; the next 8 bits is the secondary order and the
last 8 bits is the tertiary order.
See Also: Collator
See Also: RuleBasedCollator
version:
1.24 07/27/98
author:
Helena Shih, Laura Werner, Richard Gillam |
| Field Summary | |
| final public static int | NULLORDER
Null order which indicates the end of string is reached by the
cursor. | | final static int | UNMAPPEDCHARVALUE
|
| Method Summary | |
| public int | getMaxExpansion(int order)
Return the maximum length of any expansion sequences that end
with the specified comparison order.
Parameters:
order - a collation order returned by previous or next. | | public int | getOffset()
Returns the character offset in the original text corresponding to the next
collation element. | | final static boolean | isIgnorable(int order)
Check if a comparison order is ignorable. | | public int | next()
Get the next collation element in the string. | | public int | previous()
Get the previous collation element in the string. | | final public static int | primaryOrder(int order)
Return the primary component of a collation element. | | public void | reset()
Resets the cursor to the beginning of the string. | | final public static short | secondaryOrder(int order)
Return the secondary component of a collation element. | | public void | setOffset(int newOffset)
Sets the iterator to point to the collation element corresponding to
the specified character (the parameter is a CHARACTER offset in the
original string, not an offset into its corresponding sequence of
collation elements). | | public void | setText(String source)
Set a new string over which to iterate. | | public void | setText(CharacterIterator source)
Set a new string over which to iterate. | | final int | strengthOrder(int order)
Get the comparison order in the desired strength. | | final public static short | tertiaryOrder(int order)
Return the tertiary component of a collation element. |
| NULLORDER | | final public static int NULLORDER(Code) | | Null order which indicates the end of string is reached by the
cursor.
|
| UNMAPPEDCHARVALUE | | final static int UNMAPPEDCHARVALUE(Code) | | |
| CollationElementIterator | | CollationElementIterator(String sourceText, RuleBasedCollator owner)(Code) | | CollationElementIterator constructor. This takes the source string and
the collation object. The cursor will walk thru the source string based
on the predefined collation rules. If the source string is empty,
NULLORDER will be returned on the calls to next().
Parameters:
sourceText - the source string.
Parameters:
order - the collation object. |
| CollationElementIterator | | CollationElementIterator(CharacterIterator sourceText, RuleBasedCollator owner)(Code) | | CollationElementIterator constructor. This takes the source string and
the collation object. The cursor will walk thru the source string based
on the predefined collation rules. If the source string is empty,
NULLORDER will be returned on the calls to next().
Parameters:
sourceText - the source string.
Parameters:
order - the collation object. |
| getMaxExpansion | | public int getMaxExpansion(int order)(Code) | | Return the maximum length of any expansion sequences that end
with the specified comparison order.
Parameters:
order - a collation order returned by previous or next. the maximum length of any expansion sequences endingwith the specified order.
since:
1.2 |
| getOffset | | public int getOffset()(Code) | | Returns the character offset in the original text corresponding to the next
collation element. (That is, getOffset() returns the position in the text
corresponding to the collation element that will be returned by the next
call to next().) This value will always be the index of the FIRST character
corresponding to the collation element (a contracting character sequence is
when two or more characters all correspond to the same collation element).
This means if you do setOffset(x) followed immediately by getOffset(), getOffset()
won't necessarily return x.
The character offset in the original text corresponding to the collationelement that will be returned by the next call to next().
since:
1.2 |
| isIgnorable | | final static boolean isIgnorable(int order)(Code) | | Check if a comparison order is ignorable.
true if a character is ignorable, false otherwise. |
| next | | public int next()(Code) | | Get the next collation element in the string. This iterator iterates
over a sequence of collation elements that were built from the string.
Because there isn't necessarily a one-to-one mapping from characters to
collation elements, this doesn't mean the same thing as "return the
collation element [or ordering priority] of the next character in the
string".
This function returns the collation element that the iterator is currently
pointing to and then updates the internal pointer to point to the next element.
previous() updates the pointer first and then returns the element. This
means that when you change direction while iterating (i.e., call next() and
then call previous(), or call previous() and then call next()), you'll get
back the same element twice.
|
| previous | | public int previous()(Code) | | Get the previous collation element in the string. This iterator iterates
over a sequence of collation elements that were built from the string.
Because there isn't necessarily a one-to-one mapping from characters to
collation elements, this doesn't mean the same thing as "return the
collation element [or ordering priority] of the previous character in the
string".
This function updates the iterator's internal pointer to point to the
collation element preceding the one it's currently pointing to and then
returns that element, while next() returns the current element and then
updates the pointer. This means that when you change direction while
iterating (i.e., call next() and then call previous(), or call previous()
and then call next()), you'll get back the same element twice.
since:
1.2 |
| primaryOrder | | final public static int primaryOrder(int order)(Code) | | Return the primary component of a collation element.
Parameters:
order - the collation element the element's primary component |
| reset | | public void reset()(Code) | | Resets the cursor to the beginning of the string. The next call
to next() will return the first collation element in the string.
|
| secondaryOrder | | final public static short secondaryOrder(int order)(Code) | | Return the secondary component of a collation element.
Parameters:
order - the collation element the element's secondary component |
| setOffset | | public void setOffset(int newOffset)(Code) | | Sets the iterator to point to the collation element corresponding to
the specified character (the parameter is a CHARACTER offset in the
original string, not an offset into its corresponding sequence of
collation elements). The value returned by the next call to next()
will be the collation element corresponding to the specified position
in the text. If that position is in the middle of a contracting
character sequence, the result of the next call to next() is the
collation element for that sequence. This means that getOffset()
is not guaranteed to return the same value as was passed to a preceding
call to setOffset().
Parameters:
newOffset - The new character offset into the original text.
since:
1.2 |
| setText | | public void setText(String source)(Code) | | Set a new string over which to iterate.
Parameters:
source - the new source text
since:
1.2 |
| setText | | public void setText(CharacterIterator source)(Code) | | Set a new string over which to iterate.
Parameters:
source - the new source text.
since:
1.2 |
| strengthOrder | | final int strengthOrder(int order)(Code) | | Get the comparison order in the desired strength. Ignore the other
differences.
Parameters:
order - The order value |
| tertiaryOrder | | final public static short tertiaryOrder(int order)(Code) | | Return the tertiary component of a collation element.
Parameters:
order - the collation element the element's tertiary component |
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