Package com.ibm.icu.impl
Class RuleCharacterIterator
java.lang.Object
com.ibm.icu.impl.RuleCharacterIterator
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 ClassesModifier and TypeClassDescriptionstatic final class
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate String
Current variable expansion, or null if none.private int
Position within buf[].static final int
Value returned when there are no more characters to iterate.private boolean
Flag indicating whether the last character was parsed from an escape.static final int
Bitmask option to enable parsing of escape sequences.static final int
Bitmask option to enable parsing of variable names.private ParsePosition
Position of iterator.static final int
Bitmask option to enable skipping of whitespace.private SymbolTable
Symbol table used to parse and dereference variables.private String
Text being iterated. -
Constructor Summary
ConstructorsConstructorDescriptionRuleCharacterIterator
(String text, SymbolTable sym, ParsePosition pos) Constructs an iterator over the given text, starting at the given position. -
Method Summary
Modifier and TypeMethodDescriptionprivate 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.Returns a string containing the remainder of the characters to be returned by this iterator, without any option processing.int
Returns an object which, when later passed to setPos(), will restore this iterator's position.boolean
Returns true if this iterator is currently within a variable expansion.boolean
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
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.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 Details
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text
Text being iterated. -
pos
Position of iterator. -
sym
Symbol table used to parse and dereference variables. May be null. -
buf
Current variable expansion, or null if none. -
bufPos
private int bufPosPosition within buf[]. Meaningless if buf == null. -
isEscaped
private boolean isEscapedFlag indicating whether the last character was parsed from an escape. -
DONE
public static final int DONEValue returned when there are no more characters to iterate.- See Also:
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PARSE_VARIABLES
public static final int PARSE_VARIABLESBitmask option to enable parsing of variable names. If (options invalid input: '&' PARSE_VARIABLES) != 0, then an embedded variable will be expanded to its value. Variables are parsed using the SymbolTable API.- See Also:
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PARSE_ESCAPES
public static final int PARSE_ESCAPESBitmask option to enable parsing of escape sequences. If (options invalid input: '&' PARSE_ESCAPES) != 0, then an embedded escape sequence will be expanded to its value. Escapes are parsed using Utility.unescapeAndLengthAt().- See Also:
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SKIP_WHITESPACE
public static final int SKIP_WHITESPACEBitmask option to enable skipping of whitespace. If (options invalid input: '&' SKIP_WHITESPACE) != 0, then Unicode Pattern_White_Space characters will be silently skipped, as if they were not present in the input.- See Also:
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Constructor Details
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RuleCharacterIterator
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 Details
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atEnd
public boolean atEnd()Returns true if this iterator has no more characters to return. -
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. -
inVariable
public boolean inVariable()Returns true if this iterator is currently within a variable expansion. -
getPos
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
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
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() -
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
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. -
_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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