Class FilteredNormalizer2

java.lang.Object
com.ibm.icu.text.Normalizer2
com.ibm.icu.text.FilteredNormalizer2
public class FilteredNormalizer2 extends Normalizer2
Normalization filtered by a UnicodeSet. Normalizes portions of the text contained in the filter set and leaves portions not contained in the filter set unchanged. Filtering is done via UnicodeSet.span(..., UnicodeSet.SpanCondition.SIMPLE). Not-in-the-filter text is treated as "is normalized" and "quick check yes". This class implements all of (and only) the Normalizer2 API. An instance of this class is unmodifiable/immutable.
Author:
Markus W. Scherer
Status:
Stable ICU 4.4.

  • Constructor Details

    • FilteredNormalizer2

      public FilteredNormalizer2(Normalizer2 n2, UnicodeSet filterSet)
      Constructs a filtered normalizer wrapping any Normalizer2 instance and a filter set. Both are aliased and must not be modified or deleted while this object is used. The filter set should be frozen; otherwise the performance will suffer greatly.
      Parameters:
      n2 - wrapped Normalizer2 instance
      filterSet - UnicodeSet which determines the characters to be normalized
      Status:
      Stable ICU 4.4.

  • Method Details

    • normalize

      public 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.
      Specified by:
      normalize in class Normalizer2
      Parameters:
      src - source string
      dest - destination string; its contents is replaced with normalized src
      Returns:
      dest
      Status:
      Stable ICU 4.4.

    • normalize

      public 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.

      Specified by:
      normalize in class Normalizer2
      Parameters:
      src - source string
      dest - destination Appendable; gets normalized src appended
      Returns:
      dest
      Status:
      Stable ICU 4.6.

    • normalizeSecondAndAppend

      public 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.
      Specified by:
      normalizeSecondAndAppend in class Normalizer2
      Parameters:
      first - string, should be normalized
      second - string, will be normalized
      Returns:
      first
      Status:
      Stable ICU 4.4.

    • append

      public 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.
      Specified by:
      append in class Normalizer2
      Parameters:
      first - string, should be normalized
      second - string, should be normalized
      Returns:
      first
      Status:
      Stable ICU 4.4.

    • getDecomposition

      public 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.
      Specified by:
      getDecomposition in class Normalizer2
      Parameters:
      c - code point
      Returns:
      c's decomposition mapping, if any; otherwise null
      Status:
      Stable ICU 4.6.

    • 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.

      Overrides:
      getRawDecomposition in class Normalizer2
      Parameters:
      c - code point
      Returns:
      c's raw decomposition mapping, if any; otherwise null
      Status:
      Stable ICU 49.

    • 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.

      Overrides:
      composePair in class Normalizer2
      Parameters:
      a - A (normalization starter) code point.
      b - Another code point.
      Returns:
      The non-negative composite code point if there is one; otherwise a negative value.
      Status:
      Stable ICU 49.

    • 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.
      Overrides:
      getCombiningClass in class Normalizer2
      Parameters:
      c - code point
      Returns:
      c's combining class
      Status:
      Stable ICU 49.

    • isNormalized

      public 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.
      Specified by:
      isNormalized in class Normalizer2
      Parameters:
      s - input string
      Returns:
      true if s is normalized
      Status:
      Stable ICU 4.4.

    • quickCheck

      public 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.
      Specified by:
      quickCheck in class Normalizer2
      Parameters:
      s - input string
      Returns:
      the quick check result
      Status:
      Stable ICU 4.4.

    • spanQuickCheckYes

      public 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.

      Specified by:
      spanQuickCheckYes in class Normalizer2
      Parameters:
      s - input string
      Returns:
      "yes" span end index
      Status:
      Stable ICU 4.4.

    • hasBoundaryBefore

      public 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.
      Specified by:
      hasBoundaryBefore in class Normalizer2
      Parameters:
      c - character to test
      Returns:
      true if c has a normalization boundary before it
      Status:
      Stable ICU 4.4.

    • hasBoundaryAfter

      public 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().

      Specified by:
      hasBoundaryAfter in class Normalizer2
      Parameters:
      c - character to test
      Returns:
      true if c has a normalization boundary after it
      Status:
      Stable ICU 4.4.

    • isInert

      public 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().

      Specified by:
      isInert in class Normalizer2
      Parameters:
      c - character to test
      Returns:
      true if c is normalization-inert
      Status:
      Stable ICU 4.4.