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java.lang.Objectcom.ibm.icu.text.Normalizer2
public abstract class Normalizer2
Unicode normalization functionality for standard Unicode normalization or for using custom mapping tables. All instances of this class are unmodifiable/immutable.
The primary functions are to produce a normalized string and to detect whether a string is already normalized. The most commonly used normalization forms are those defined in http://www.unicode.org/unicode/reports/tr15/ However, this API supports additional normalization forms for specialized purposes. For example, NFKC_Casefold is provided via getInstance("nfkc_cf", COMPOSE) and can be used in implementations of UTS #46.
Not only are the standard compose and decompose modes supplied, but additional modes are provided as documented in the Mode enum.
Some of the functions in this class identify normalization boundaries. At a normalization boundary, the portions of the string before it and starting from it do not interact and can be handled independently.
The spanQuickCheckYes() stops at a normalization boundary. When the goal is a normalized string, then the text before the boundary can be copied, and the remainder can be processed with normalizeSecondAndAppend().
The hasBoundaryBefore(), hasBoundaryAfter() and isInert() functions test whether a character is guaranteed to be at a normalization boundary, regardless of context. This is used for moving from one normalization boundary to the next or preceding boundary, and for performing iterative normalization.
Iterative normalization is useful when only a small portion of a longer string needs to be processed. For example, in ICU, iterative normalization is used by the NormalizationTransliterator (to avoid replacing already-normalized text) and ucol_nextSortKeyPart() (to process only the substring for which sort key bytes are computed).
The set of normalization boundaries returned by these functions may not be complete: There may be more boundaries that could be returned. Different functions may return different boundaries.
Nested Class Summary | |
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static class |
Normalizer2.Mode
Constants for normalization modes. |
Constructor Summary | |
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protected |
Normalizer2()
Deprecated. This API is ICU internal only. |
Method Summary | |
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abstract StringBuilder |
append(StringBuilder first,
CharSequence second)
Appends the second string to the first string (merging them at the boundary) and returns the first string. |
static Normalizer2 |
getInstance(InputStream data,
String name,
Normalizer2.Mode mode)
Returns a Normalizer2 instance which uses the specified data file (an ICU data file if data=null, or else custom binary data) and which composes or decomposes text according to the specified mode. |
abstract boolean |
hasBoundaryAfter(int c)
Tests if the character always has a normalization boundary after it, regardless of context. |
abstract boolean |
hasBoundaryBefore(int c)
Tests if the character always has a normalization boundary before it, regardless of context. |
abstract boolean |
isInert(int c)
Tests if the character is normalization-inert. |
abstract boolean |
isNormalized(CharSequence s)
Tests if the string is normalized. |
String |
normalize(CharSequence src)
Returns the normalized form of the source string. |
abstract Appendable |
normalize(CharSequence src,
Appendable dest)
Writes the normalized form of the source string to the destination Appendable and returns the destination Appendable. |
abstract StringBuilder |
normalize(CharSequence src,
StringBuilder dest)
Writes the normalized form of the source string to the destination string (replacing its contents) and returns the destination string. |
abstract StringBuilder |
normalizeSecondAndAppend(StringBuilder first,
CharSequence second)
Appends the normalized form of the second string to the first string (merging them at the boundary) and returns the first string. |
abstract Normalizer.QuickCheckResult |
quickCheck(CharSequence s)
Tests if the string is normalized. |
abstract int |
spanQuickCheckYes(CharSequence s)
Returns the end of the normalized substring of the input string. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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protected Normalizer2()
Method Detail |
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public static Normalizer2 getInstance(InputStream data, String name, Normalizer2.Mode mode)
data
- the binary, big-endian normalization (.nrm file) data, or null for ICU dataname
- "nfc" or "nfkc" or "nfkc_cf" or name of custom data filemode
- normalization mode (compose or decompose etc.)
public String normalize(CharSequence src)
src
- source string
public abstract StringBuilder normalize(CharSequence src, StringBuilder dest)
src
- source stringdest
- destination string; its contents is replaced with normalized src
public abstract Appendable normalize(CharSequence src, Appendable dest)
src
- source stringdest
- destination Appendable; gets normalized src appended
public abstract StringBuilder normalizeSecondAndAppend(StringBuilder first, CharSequence second)
first
- string, should be normalizedsecond
- string, will be normalized
public abstract StringBuilder append(StringBuilder first, CharSequence second)
first
- string, should be normalizedsecond
- string, should be normalized
public abstract boolean isNormalized(CharSequence s)
s
- input string
public abstract Normalizer.QuickCheckResult quickCheck(CharSequence s)
s
- input string
public abstract int spanQuickCheckYes(CharSequence s)
end=spanQuickCheckYes(s);
the substring s.subSequence(0, end)
will pass the quick check with a "yes" result.
The returned end index is usually one or more characters before the "no" or "maybe" character: The end index is at a normalization boundary. (See the class documentation for more about normalization boundaries.)
When the goal is a normalized string and most input strings are expected to be normalized already, then call this method, and if it returns a prefix shorter than the input string, copy that prefix and use normalizeSecondAndAppend() for the remainder.
s
- input string
public abstract boolean hasBoundaryBefore(int c)
c
- character to test
public abstract boolean hasBoundaryAfter(int c)
Note that this operation may be significantly slower than hasBoundaryBefore().
c
- character to test
public abstract boolean isInert(int c)
Note that this operation may be significantly slower than hasBoundaryBefore().
c
- character to test
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