Home | History | Annotate | Download | only in impl 
      1 //  2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html#License
      3 /*
      4  *******************************************************************************
      5  * Copyright (C) 1996-2010, International Business Machines Corporation and    *
      6  * others. All Rights Reserved.                                                *
      7  *******************************************************************************
      8  */
      9 
     10 package com.ibm.icu.impl;
     11 
     12 import java.text.CharacterIterator;
     13 
     14 import com.ibm.icu.text.UCharacterIterator;
     15 
     16 /**
     17  * This class is a wrapper around UCharacterIterator and implements the
     18  * CharacterIterator protocol
     19  * @author ram
     20  */
     21 public class UCharacterIteratorWrapper implements CharacterIterator{
     22 
     23     public UCharacterIteratorWrapper(UCharacterIterator iter){
     24         this.iterator = iter;
     25     }
     26 
     27     private UCharacterIterator iterator;
     28 
     29 
     30     /**
     31      * Sets the position to getBeginIndex() and returns the character at that
     32      * position.
     33      * @return the first character in the text, or DONE if the text is empty
     34      * @see #getBeginIndex()
     35      */
     36     @Override
     37     public char first(){
     38         //UCharacterIterator always iterates from 0 to length
     39         iterator.setToStart();
     40         return (char)iterator.current();
     41     }
     42 
     43     /**
     44      * Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)
     45      * and returns the character at that position.
     46      * @return the last character in the text, or DONE if the text is empty
     47      * @see #getEndIndex()
     48      */
     49     @Override
     50     public char last(){
     51         iterator.setToLimit();
     52         return (char)iterator.previous();
     53     }
     54 
     55     /**
     56      * Gets the character at the current position (as returned by getIndex()).
     57      * @return the character at the current position or DONE if the current
     58      * position is off the end of the text.
     59      * @see #getIndex()
     60      */
     61     @Override
     62     public char current(){
     63         return (char) iterator.current();
     64     }
     65 
     66     /**
     67      * Increments the iterator's index by one and returns the character
     68      * at the new index.  If the resulting index is greater or equal
     69      * to getEndIndex(), the current index is reset to getEndIndex() and
     70      * a value of DONE is returned.
     71      * @return the character at the new position or DONE if the new
     72      * position is off the end of the text range.
     73      */
     74     @Override
     75     public char next(){
     76         //pre-increment
     77         iterator.next();
     78         return (char) iterator.current();
     79     }
     80 
     81     /**
     82      * Decrements the iterator's index by one and returns the character
     83      * at the new index. If the current index is getBeginIndex(), the index
     84      * remains at getBeginIndex() and a value of DONE is returned.
     85      * @return the character at the new position or DONE if the current
     86      * position is equal to getBeginIndex().
     87      */
     88     @Override
     89     public char previous(){
     90         //pre-decrement
     91         return (char) iterator.previous();
     92     }
     93 
     94     /**
     95      * Sets the position to the specified position in the text and returns that
     96      * character.
     97      * @param position the position within the text.  Valid values range from
     98      * getBeginIndex() to getEndIndex().  An IllegalArgumentException is thrown
     99      * if an invalid value is supplied.
    100      * @return the character at the specified position or DONE if the specified position is equal to getEndIndex()
    101      */
    102     @Override
    103     public char setIndex(int position){
    104         iterator.setIndex(position);
    105         return (char) iterator.current();
    106     }
    107 
    108     /**
    109      * Returns the start index of the text.
    110      * @return the index at which the text begins.
    111      */
    112     @Override
    113     public int getBeginIndex(){
    114         //UCharacterIterator always starts from 0
    115         return 0;
    116     }
    117 
    118     /**
    119      * Returns the end index of the text.  This index is the index of the first
    120      * character following the end of the text.
    121      * @return the index after the last character in the text
    122      */
    123     @Override
    124     public int getEndIndex(){
    125         return iterator.getLength();
    126     }
    127 
    128     /**
    129      * Returns the current index.
    130      * @return the current index.
    131      */
    132     @Override
    133     public int getIndex(){
    134         return iterator.getIndex();
    135     }
    136 
    137     /**
    138      * Create a copy of this iterator
    139      * @return A copy of this
    140      */
    141     @Override
    142     public Object clone(){
    143         try {
    144             UCharacterIteratorWrapper result = (UCharacterIteratorWrapper) super.clone();
    145             result.iterator = (UCharacterIterator)this.iterator.clone();
    146             return result;
    147         } catch (CloneNotSupportedException e) {
    148             return null; // only invoked if bad underlying character iterator
    149         }
    150     }
    151 
    152 }
    153 
    154