Normalizer2

append

public 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. The result is normalized if both the strings were normalized. The first and second strings must be different objects.

composePair

public int composePair (int a, 
                int b)

Performs pairwise composition of a & b and returns the composite if there is one.

Returns a composite code point c only if c has a two-way mapping to a+b. In standard Unicode normalization, this means that c has a canonical decomposition to a+b and c does not have the Full_Composition_Exclusion property.

This function is independent of the mode of the Normalizer2. The default implementation returns a negative value.

getCombiningClass

public int getCombiningClass (int c)

Gets the combining class of c. The default implementation returns 0 but all standard implementations return the Unicode Canonical_Combining_Class value.

getDecomposition

public abstract String getDecomposition (int c)

Gets the decomposition mapping of c. Roughly equivalent to normalizing the String form of c on a DECOMPOSE Normalizer2 instance, but much faster, and except that this function returns null if c does not have a decomposition mapping in this instance's data. This function is independent of the mode of the Normalizer2.

getInstance

public static Normalizer2 getInstance (InputStream data, 
                String name, 
                Normalizer2.Mode mode)

This method was deprecated in API level 31.
Don't use because the binary data format is not stable across API levels.

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. Returns an unmodifiable singleton instance.

• Use data=null for data files that are part of ICU's own data.
• Use name="nfc" and COMPOSE/DECOMPOSE for Unicode standard NFC/NFD.
• Use name="nfkc" and COMPOSE/DECOMPOSE for Unicode standard NFKC/NFKD.
• Use name="nfkc_cf" and COMPOSE for Unicode standard NFKC_CF=NFKC_Casefold.

Any IOException is wrapped into a ICUUncheckedIOException.

getNFCInstance

public static Normalizer2 getNFCInstance ()

Returns a Normalizer2 instance for Unicode NFC normalization. Same as getInstance(null, "nfc", Mode.COMPOSE). Returns an unmodifiable singleton instance.

getNFDInstance

public static Normalizer2 getNFDInstance ()

Returns a Normalizer2 instance for Unicode NFD normalization. Same as getInstance(null, "nfc", Mode.DECOMPOSE). Returns an unmodifiable singleton instance.

getNFKCCasefoldInstance

public static Normalizer2 getNFKCCasefoldInstance ()

Returns a Normalizer2 instance for Unicode toNFKC_Casefold() normalization which is equivalent to applying the NFKC_Casefold mappings and then NFC. See https://www.unicode.org/reports/tr44/#NFKC_Casefold

Same as getInstance(null, "nfkc_cf", Mode.COMPOSE). Returns an unmodifiable singleton instance.

getNFKCInstance

public static Normalizer2 getNFKCInstance ()

Returns a Normalizer2 instance for Unicode NFKC normalization. Same as getInstance(null, "nfkc", Mode.COMPOSE). Returns an unmodifiable singleton instance.

getNFKDInstance

public static Normalizer2 getNFKDInstance ()

Returns a Normalizer2 instance for Unicode NFKD normalization. Same as getInstance(null, "nfkc", Mode.DECOMPOSE). Returns an unmodifiable singleton instance.

getRawDecomposition

public String getRawDecomposition (int c)

Gets the raw decomposition mapping of c.

This is similar to the getDecomposition() method but returns the raw decomposition mapping as specified in UnicodeData.txt or (for custom data) in the mapping files processed by the gennorm2 tool. By contrast, getDecomposition() returns the processed, recursively-decomposed version of this mapping.

When used on a standard NFKC Normalizer2 instance, getRawDecomposition() returns the Unicode Decomposition_Mapping (dm) property.

When used on a standard NFC Normalizer2 instance, it returns the Decomposition_Mapping only if the Decomposition_Type (dt) is Canonical (Can); in this case, the result contains either one or two code points (=1..4 Java chars).

This function is independent of the mode of the Normalizer2. The default implementation returns null.

hasBoundaryAfter

public abstract boolean hasBoundaryAfter (int c)

Tests if the character always has a normalization boundary after it, regardless of context. If true, then the character does not normalization-interact with following characters. In other words, a string containing this character can be normalized by processing portions up to this character and after this character independently. This is used for iterative normalization. See the class documentation for details.

Note that this operation may be significantly slower than hasBoundaryBefore().

hasBoundaryBefore

public abstract boolean hasBoundaryBefore (int c)

Tests if the character always has a normalization boundary before it, regardless of context. If true, then the character does not normalization-interact with preceding characters. In other words, a string containing this character can be normalized by processing portions before this character and starting from this character independently. This is used for iterative normalization. See the class documentation for details.

isInert

public abstract boolean isInert (int c)

Tests if the character is normalization-inert. If true, then the character does not change, nor normalization-interact with preceding or following characters. In other words, a string containing this character can be normalized by processing portions before this character and after this character independently. This is used for iterative normalization. See the class documentation for details.

Note that this operation may be significantly slower than hasBoundaryBefore().

isNormalized

public abstract boolean isNormalized (CharSequence s)

Tests if the string is normalized. Internally, in cases where the quickCheck() method would return "maybe" (which is only possible for the two COMPOSE modes) this method resolves to "yes" or "no" to provide a definitive result, at the cost of doing more work in those cases.

normalize

public String normalize (CharSequence src)

Returns the normalized form of the source string.

normalize

public 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. The source and destination strings must be different objects.

normalize

public abstract Appendable normalize (CharSequence src, 
                Appendable dest)

Writes the normalized form of the source string to the destination Appendable and returns the destination Appendable. The source and destination strings must be different objects.

Any IOException is wrapped into a ICUUncheckedIOException.

normalizeSecondAndAppend

public 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. The result is normalized if the first string was normalized. The first and second strings must be different objects.

quickCheck

public abstract Normalizer.QuickCheckResult quickCheck (CharSequence s)

Tests if the string is normalized. For the two COMPOSE modes, the result could be "maybe" in cases that would take a little more work to resolve definitively. Use spanQuickCheckYes() and normalizeSecondAndAppend() for a faster combination of quick check + normalization, to avoid re-checking the "yes" prefix.

spanQuickCheckYes

public abstract int spanQuickCheckYes (CharSequence s)

Returns the end of the normalized substring of the input string. In other words, with 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.