Package com.ibm.icu.impl
Class RuleCharacterIterator
- java.lang.Object
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- com.ibm.icu.impl.RuleCharacterIterator
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public class RuleCharacterIterator extends java.lang.Object
An iterator that returns 32-bit code points. This class is deliberately not related to any of the JDK or ICU4J character iterator classes in order to minimize complexity.- Since:
- ICU 2.8
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
RuleCharacterIterator.Position
For use withgetPos(Position)
&setPos(Position)
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Field Summary
Fields Modifier and Type Field Description private java.lang.String
buf
Current variable expansion, or null if none.private int
bufPos
Position within buf[].static int
DONE
Value returned when there are no more characters to iterate.private boolean
isEscaped
Flag indicating whether the last character was parsed from an escape.static int
PARSE_ESCAPES
Bitmask option to enable parsing of escape sequences.static int
PARSE_VARIABLES
Bitmask option to enable parsing of variable names.private java.text.ParsePosition
pos
Position of iterator.static int
SKIP_WHITESPACE
Bitmask option to enable skipping of whitespace.private SymbolTable
sym
Symbol table used to parse and dereference variables.private java.lang.String
text
Text being iterated.
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Constructor Summary
Constructors Constructor Description RuleCharacterIterator(java.lang.String text, SymbolTable sym, java.text.ParsePosition pos)
Constructs an iterator over the given text, starting at the given position.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private void
_advance(int count)
Advances the position by the given amount.private int
_current()
Returns the current 32-bit code point without parsing escapes, parsing variables, or skipping whitespace.boolean
atEnd()
Returns true if this iterator has no more characters to return.java.lang.String
getCurrentBuffer()
Returns a string containing the remainder of the characters to be returned by this iterator, without any option processing.int
getCurrentBufferPos()
RuleCharacterIterator.Position
getPos(RuleCharacterIterator.Position p)
Returns an object which, when later passed to setPos(), will restore this iterator's position.boolean
inVariable()
Returns true if this iterator is currently within a variable expansion.boolean
isEscaped()
Returns true if the last character returned by next() was escaped.void
jumpahead(int count)
Advances the position by the given number of 16-bit code units.int
next(int options)
Returns the next character using the given options, or DONE if there are no more characters, and advance the position to the next character.void
setPos(RuleCharacterIterator.Position p)
Restores this iterator to the position it had when getPos() returned the given object.void
skipIgnored(int options)
Skips ahead past any ignored characters, as indicated by the given options.java.lang.String
toString()
Returns a string representation of this object, consisting of the characters being iterated, with a '|' marking the current position.
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Field Detail
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text
private java.lang.String text
Text being iterated.
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pos
private java.text.ParsePosition pos
Position of iterator.
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sym
private SymbolTable sym
Symbol table used to parse and dereference variables. May be null.
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buf
private java.lang.String buf
Current variable expansion, or null if none.
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bufPos
private int bufPos
Position within buf[]. Meaningless if buf == null.
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isEscaped
private boolean isEscaped
Flag indicating whether the last character was parsed from an escape.
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DONE
public static final int DONE
Value returned when there are no more characters to iterate.- See Also:
- Constant Field Values
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PARSE_VARIABLES
public static final int PARSE_VARIABLES
Bitmask option to enable parsing of variable names. If (options & PARSE_VARIABLES) != 0, then an embedded variable will be expanded to its value. Variables are parsed using the SymbolTable API.- See Also:
- Constant Field Values
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PARSE_ESCAPES
public static final int PARSE_ESCAPES
Bitmask option to enable parsing of escape sequences. If (options & PARSE_ESCAPES) != 0, then an embedded escape sequence will be expanded to its value. Escapes are parsed using Utility.unescapeAndLengthAt().- See Also:
- Constant Field Values
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SKIP_WHITESPACE
public static final int SKIP_WHITESPACE
Bitmask option to enable skipping of whitespace. If (options & SKIP_WHITESPACE) != 0, then Unicode Pattern_White_Space characters will be silently skipped, as if they were not present in the input.- See Also:
- Constant Field Values
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Constructor Detail
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RuleCharacterIterator
public RuleCharacterIterator(java.lang.String text, SymbolTable sym, java.text.ParsePosition pos)
Constructs an iterator over the given text, starting at the given position.- Parameters:
text
- the text to be iteratedsym
- the symbol table, or null if there is none. If sym is null, then variables will not be dereferenced, even if the PARSE_VARIABLES option is set.pos
- upon input, the index of the next character to return. If a variable has been dereferenced, then pos will not increment as characters of the variable value are iterated.
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Method Detail
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atEnd
public boolean atEnd()
Returns true if this iterator has no more characters to return.
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next
public int next(int options)
Returns the next character using the given options, or DONE if there are no more characters, and advance the position to the next character.- Parameters:
options
- one or more of the following options, bitwise-OR-ed together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE.- Returns:
- the current 32-bit code point, or DONE
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isEscaped
public boolean isEscaped()
Returns true if the last character returned by next() was escaped. This will only be the case if the option passed in to next() included PARSE_ESCAPED and the next character was an escape sequence.
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inVariable
public boolean inVariable()
Returns true if this iterator is currently within a variable expansion.
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getPos
public RuleCharacterIterator.Position getPos(RuleCharacterIterator.Position p)
Returns an object which, when later passed to setPos(), will restore this iterator's position. Usage idiom: RuleCharacterIterator iterator = ...; Position pos = iterator.getPos(null); // allocate position object for (;;) { pos = iterator.getPos(pos); // reuse position object int c = iterator.next(...); ... } iterator.setPos(pos);- Parameters:
p
- a position object previously returned bygetPos()
, or null. If not null, it will be updated and returned. If null, a new position object will be allocated and returned.- Returns:
- a position object which may be passed to setPos(), either
p
, or ifp
== null, a newly-allocated object
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setPos
public void setPos(RuleCharacterIterator.Position p)
Restores this iterator to the position it had when getPos() returned the given object.- Parameters:
p
- a position object previously returned by getPos()
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skipIgnored
public void skipIgnored(int options)
Skips ahead past any ignored characters, as indicated by the given options. This is useful in conjunction with the lookahead() method. Currently, this only has an effect for SKIP_WHITESPACE.- Parameters:
options
- one or more of the following options, bitwise-OR-ed together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE.
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getCurrentBuffer
public java.lang.String getCurrentBuffer()
Returns a string containing the remainder of the characters to be returned by this iterator, without any option processing. If the iterator is currently within a variable expansion, this will only extend to the end of the variable expansion. This method, together with getCurrentBufferPos() (which replace the former lookahead()), is provided so that iterators may interoperate with string-based APIs. The typical sequence of calls is to call skipIgnored(), then call these methods, then parse that substring, then call jumpahead() to resynchronize the iterator.- Returns:
- a string containing the characters to be returned by future calls to next()
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getCurrentBufferPos
public int getCurrentBufferPos()
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jumpahead
public void jumpahead(int count)
Advances the position by the given number of 16-bit code units. This is useful in conjunction with getCurrentBuffer()+getCurrentBufferPos() (formerly lookahead()).- Parameters:
count
- the number of 16-bit code units to jump over
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toString
public java.lang.String toString()
Returns a string representation of this object, consisting of the characters being iterated, with a '|' marking the current position. Position within an expanded variable is not indicated.- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string representation of this object
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_current
private int _current()
Returns the current 32-bit code point without parsing escapes, parsing variables, or skipping whitespace.- Returns:
- the current 32-bit code point
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_advance
private void _advance(int count)
Advances the position by the given amount.- Parameters:
count
- the number of 16-bit code units to advance past
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