Package com.ibm.icu.text

Class UCharacterIterator

  • All Implemented Interfaces:
    UForwardCharacterIterator, Cloneable
    public abstract class UCharacterIterator
extends Object
implements Cloneable, UForwardCharacterIterator
    Abstract class that defines an API for iteration on text objects.This is an interface for forward and backward iteration and random access into a text object. Forward iteration is done with post-increment and backward iteration is done with pre-decrement semantics, while the java.text.CharacterIterator interface methods provided forward iteration with "pre-increment" and backward iteration with pre-decrement semantics. This API is more efficient for forward iteration over code points. The other major difference is that this API can do both code unit and code point iteration, java.text.CharacterIterator can only iterate over code units and is limited to BMP (0 - 0xFFFF)
    Author:
    Ram
    Status:
    Stable ICU 2.4.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected UCharacterIterator()
      Protected default constructor for the subclasses

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      UCharacterIterator clone()
      Creates a copy of this iterator, independent from other iterators.
      abstract int current()
      Returns the code unit at the current index.
      int currentCodePoint()
      Returns the codepoint at the current index.
      CharacterIterator getCharacterIterator()
      Returns a java.text.CharacterIterator object for the underlying text of this iterator.
      abstract int getIndex()
      Gets the current index in text.
      static UCharacterIterator getInstance​(char[] source)
      Returns a UCharacterIterator object given a source character array.
      static UCharacterIterator getInstance​(char[] source, int start, int limit)
      Returns a UCharacterIterator object given a source character array.
      static UCharacterIterator getInstance​(Replaceable source)
      Returns a UCharacterIterator object given a Replaceable object.
      static UCharacterIterator getInstance​(String source)
      Returns a UCharacterIterator object given a source string.
      static UCharacterIterator getInstance​(StringBuffer source)
      Returns a UCharacterIterator object given a source StringBuffer.
      static UCharacterIterator getInstance​(CharacterIterator source)
      Returns a UCharacterIterator object given a CharacterIterator.
      abstract int getLength()
      Returns the length of the text
      String getText()
      Convenience method for returning the underlying text storage as as string
      int getText​(char[] fillIn)
      Convenience override for getText(char[], int) that provides an offset of 0.
      abstract int getText​(char[] fillIn, int offset)
      Fills the buffer with the underlying text storage of the iterator If the buffer capacity is not enough a exception is thrown.
      int moveCodePointIndex​(int delta)
      Moves the current position by the number of code points specified, either forward or backward depending on the sign of delta (positive or negative respectively).
      int moveIndex​(int delta)
      Moves the current position by the number of code units specified, either forward or backward depending on the sign of delta (positive or negative respectively).
      abstract int next()
      Returns the UTF16 code unit at index, and increments to the next code unit (post-increment semantics).
      int nextCodePoint()
      Returns the code point at index, and increments to the next code point (post-increment semantics).
      abstract int previous()
      Decrement to the position of the previous code unit in the text, and return it (pre-decrement semantics).
      int previousCodePoint()
      Retreat to the start of the previous code point in the text, and return it (pre-decrement semantics).
      abstract void setIndex​(int index)
      Sets the index to the specified index in the text.
      void setToLimit()
      Sets the current index to the limit.
      void setToStart()
      Sets the current index to the start.

    • Constructor Detail

      • UCharacterIterator

        protected UCharacterIterator()
        Protected default constructor for the subclasses
        Status:
        Stable ICU 2.4.

    • Method Detail

      • getInstance

        public static final UCharacterIterator getInstance​(Replaceable source)
        Returns a UCharacterIterator object given a Replaceable object.
        Parameters:
        source - a valid source as a Replaceable object
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getInstance

        public static final UCharacterIterator getInstance​(String source)
        Returns a UCharacterIterator object given a source string.
        Parameters:
        source - a string
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getInstance

        public static final UCharacterIterator getInstance​(char[] source)
        Returns a UCharacterIterator object given a source character array.
        Parameters:
        source - an array of UTF-16 code units
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getInstance

        public static final UCharacterIterator getInstance​(char[] source,
                                                   int start,
                                                   int limit)
        Returns a UCharacterIterator object given a source character array.
        Parameters:
        source - an array of UTF-16 code units
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getInstance

        public static final UCharacterIterator getInstance​(StringBuffer source)
        Returns a UCharacterIterator object given a source StringBuffer.
        Parameters:
        source - an string buffer of UTF-16 code units
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getInstance

        public static final UCharacterIterator getInstance​(CharacterIterator source)
        Returns a UCharacterIterator object given a CharacterIterator.
        Parameters:
        source - a valid CharacterIterator object.
        Returns:
        UCharacterIterator object
        Throws:
        IllegalArgumentException - if the argument is null
        Status:
        Stable ICU 2.4.

      • getCharacterIterator

        public CharacterIterator getCharacterIterator()
        Returns a java.text.CharacterIterator object for the underlying text of this iterator. The returned iterator is independent of this iterator.
        Returns:
        java.text.CharacterIterator object
        Status:
        Stable ICU 2.4.

      • current

        public abstract int current()
        Returns the code unit at the current index. If index is out of range, returns DONE. Index is not changed.
        Returns:
        current code unit
        Status:
        Stable ICU 2.4.

      • currentCodePoint

        public int currentCodePoint()
        Returns the codepoint at the current index. If the current index is invalid, DONE is returned. If the current index points to a lead surrogate, and there is a following trail surrogate, then the code point is returned. Otherwise, the code unit at index is returned. Index is not changed.
        Returns:
        current codepoint
        Status:
        Stable ICU 2.4.

      • getLength

        public abstract int getLength()
        Returns the length of the text
        Returns:
        length of the text
        Status:
        Stable ICU 2.4.

      • getIndex

        public abstract int getIndex()
        Gets the current index in text.
        Returns:
        current index in text.
        Status:
        Stable ICU 2.4.

      • next

        public abstract int next()
        Returns the UTF16 code unit at index, and increments to the next code unit (post-increment semantics). If index is out of range, DONE is returned, and the iterator is reset to the limit of the text.
        Specified by:
        next in interface UForwardCharacterIterator
        Returns:
        the next UTF16 code unit, or DONE if the index is at the limit of the text.
        Status:
        Stable ICU 2.4.

      • nextCodePoint

        public int nextCodePoint()
        Returns the code point at index, and increments to the next code point (post-increment semantics). If index does not point to a valid surrogate pair, the behavior is the same as next(). Otherwise the iterator is incremented past the surrogate pair, and the code point represented by the pair is returned.
        Specified by:
        nextCodePoint in interface UForwardCharacterIterator
        Returns:
        the next codepoint in text, or DONE if the index is at the limit of the text.
        Status:
        Stable ICU 2.4.

      • previous

        public abstract int previous()
        Decrement to the position of the previous code unit in the text, and return it (pre-decrement semantics). If the resulting index is less than 0, the index is reset to 0 and DONE is returned.
        Returns:
        the previous code unit in the text, or DONE if the new index is before the start of the text.
        Status:
        Stable ICU 2.4.

      • previousCodePoint

        public int previousCodePoint()
        Retreat to the start of the previous code point in the text, and return it (pre-decrement semantics). If the index is not preceded by a valid surrogate pair, the behavior is the same as previous(). Otherwise the iterator is decremented to the start of the surrogate pair, and the code point represented by the pair is returned.
        Returns:
        the previous code point in the text, or DONE if the new index is before the start of the text.
        Status:
        Stable ICU 2.4.

      • setIndex

        public abstract void setIndex​(int index)
        Sets the index to the specified index in the text.
        Parameters:
        index - the index within the text.
        Throws:
        IndexOutOfBoundsException - is thrown if an invalid index is supplied
        Status:
        Stable ICU 2.4.

      • setToLimit

        public void setToLimit()
        Sets the current index to the limit.
        Status:
        Stable ICU 2.4.

      • setToStart

        public void setToStart()
        Sets the current index to the start.
        Status:
        Stable ICU 2.4.

      • getText

        public abstract int getText​(char[] fillIn,
                            int offset)
        Fills the buffer with the underlying text storage of the iterator If the buffer capacity is not enough a exception is thrown. The capacity of the fill in buffer should at least be equal to length of text in the iterator obtained by calling getLength()). Usage: 
                 UChacterIterator iter = new UCharacterIterator.getInstance(text);
         char[] buf = new char[iter.getLength()];
         iter.getText(buf);

         OR
         char[] buf= new char[1];
         int len = 0;
         for(;;){
             try{
                 len = iter.getText(buf);
                 break;
             }catch(IndexOutOfBoundsException e){
                 buf = new char[iter.getLength()];
             }
         }
        Parameters:
        fillIn - an array of chars to fill with the underlying UTF-16 code units.
        offset - the position within the array to start putting the data.
        Returns:
        the number of code units added to fillIn, as a convenience
        Throws:
        IndexOutOfBoundsException - exception if there is not enough room after offset in the array, or if offset < 0.
        Status:
        Stable ICU 2.4.

      • getText

        public final int getText​(char[] fillIn)
        Convenience override for getText(char[], int) that provides an offset of 0.
        Parameters:
        fillIn - an array of chars to fill with the underlying UTF-16 code units.
        Returns:
        the number of code units added to fillIn, as a convenience
        Throws:
        IndexOutOfBoundsException - exception if there is not enough room in the array.
        Status:
        Stable ICU 2.4.

      • getText

        public String getText()
        Convenience method for returning the underlying text storage as as string
        Returns:
        the underlying text storage in the iterator as a string
        Status:
        Stable ICU 2.4.

      • moveIndex

        public int moveIndex​(int delta)
        Moves the current position by the number of code units specified, either forward or backward depending on the sign of delta (positive or negative respectively). If the resulting index would be less than zero, the index is set to zero, and if the resulting index would be greater than limit, the index is set to limit.
        Parameters:
        delta - the number of code units to move the current index.
        Returns:
        the new index.
        Throws:
        IndexOutOfBoundsException - is thrown if an invalid index is supplied
        Status:
        Stable ICU 2.4.

      • moveCodePointIndex

        public int moveCodePointIndex​(int delta)
        Moves the current position by the number of code points specified, either forward or backward depending on the sign of delta (positive or negative respectively). If the current index is at a trail surrogate then the first adjustment is by code unit, and the remaining adjustments are by code points. If the resulting index would be less than zero, the index is set to zero, and if the resulting index would be greater than limit, the index is set to limit.
        Parameters:
        delta - the number of code units to move the current index.
        Returns:
        the new index
        Throws:
        IndexOutOfBoundsException - is thrown if an invalid delta is supplied
        Status:
        Stable ICU 2.4.