Package com.yahoo.language.simple.kstem

Class CharacterUtils

java.lang.Object
com.yahoo.language.simple.kstem.CharacterUtils
public abstract class CharacterUtils extends Object
CharacterUtils provides a unified interface to Character-related operations to implement backwards compatible character operations.

  • Constructor Details

    • CharacterUtils

      public CharacterUtils()

  • Method Details

    • getInstance

      public static CharacterUtils getInstance()
      Returns a CharacterUtils implementation.

    • codePointAt

      public abstract int codePointAt(CharSequence seq, int offset)
      Returns the code point at the given index of the CharSequence.
      Parameters:
      seq - a character sequence
      offset - the offset to the char values in the chars array to be converted
      Returns:
      the Unicode code point at the given index
      Throws:
      NullPointerException - - if the sequence is null.
      IndexOutOfBoundsException - - if the value offset is negative or not less than the length of the character sequence.

    • codePointAt

      public abstract int codePointAt(char[] chars, int offset, int limit)
      Returns the code point at the given index of the char array where only elements with index less than the limit are used.
      Parameters:
      chars - a character array
      offset - the offset to the char values in the chars array to be converted
      limit - the index afer the last element that should be used to calculate codepoint.
      Returns:
      the Unicode code point at the given index
      Throws:
      NullPointerException - - if the array is null.
      IndexOutOfBoundsException - - if the value offset is negative or not less than the length of the char array.

    • codePointCount

      public abstract int codePointCount(CharSequence seq)
      Return the number of characters in seq.

    • newCharacterBuffer

      public static CharacterUtils.CharacterBuffer newCharacterBuffer(int bufferSize)
      Creates a new CharacterUtils.CharacterBuffer and allocates a char[] of the given bufferSize.
      Parameters:
      bufferSize - the internal char buffer size, must be >= 2
      Returns:
      a new CharacterUtils.CharacterBuffer instance.

    • toLowerCase

      public final void toLowerCase(char[] buffer, int offset, int limit)
      Converts each unicode codepoint to lowerCase via Character.toLowerCase(int) starting at the given offset.
      Parameters:
      buffer - the char buffer to lowercase
      offset - the offset to start at
      limit - the max char in the buffer to lower case

    • toUpperCase

      public final void toUpperCase(char[] buffer, int offset, int limit)
      Converts each unicode codepoint to UpperCase via Character.toUpperCase(int) starting at the given offset.
      Parameters:
      buffer - the char buffer to UPPERCASE
      offset - the offset to start at
      limit - the max char in the buffer to lower case

    • toCodePoints

      public final int toCodePoints(char[] src, int srcOff, int srcLen, int[] dest, int destOff)
      Converts a sequence of Java characters to a sequence of unicode code points.
      Returns:
      the number of code points written to the destination buffer

    • toChars

      public final int toChars(int[] src, int srcOff, int srcLen, char[] dest, int destOff)
      Converts a sequence of unicode code points to a sequence of Java characters.
      Returns:
      the number of chars written to the destination buffer

    • fill

      public abstract boolean fill(CharacterUtils.CharacterBuffer buffer, Reader reader, int numChars) throws IOException
      Fills the CharacterUtils.CharacterBuffer with characters read from the given reader Reader. This method tries to read numChars characters into the CharacterUtils.CharacterBuffer, each call to fill will start filling the buffer from offset 0 up to numChars. In case code points can span across 2 java characters, this method may only fill numChars - 1 characters in order not to split in the middle of a surrogate pair, even if there are remaining characters in the Reader.

      This method guarantees that the given CharacterUtils.CharacterBuffer will never contain a high surrogate character as the last element in the buffer unless it is the last available character in the reader. In other words, high and low surrogate pairs will always be preserved across buffer boarders.

      A return value of false means that this method call exhausted the reader, but there may be some bytes which have been read, which can be verified by checking whether buffer.getLength() > 0.

      Parameters:
      buffer - the buffer to fill.
      reader - the reader to read characters from.
      numChars - the number of chars to read
      Returns:
      false if and only if reader.read returned -1 while trying to fill the buffer
      Throws:
      IOException - if the reader throws an IOException.

    • fill

      public final boolean fill(CharacterUtils.CharacterBuffer buffer, Reader reader) throws IOException
      Convenience method which calls fill(buffer, reader, buffer.buffer.length).
      Throws:
      IOException

    • offsetByCodePoints

      public abstract int offsetByCodePoints(char[] buf, int start, int count, int index, int offset)
      Return the index within buf[start:start+count] which is by offset code points from index.