Interface CharSequence
- All Known Implementing Classes:
CharBuffer,Segment,String,StringBuffer,StringBuilder
CharSequence is a readable sequence ofchar values. Thisinterface provides uniform, read-only access to many different kinds ofchar sequences.Achar value represents a character in theBasicMultilingual Plane (BMP) or a surrogate. Refer toUnicode Character Representation for details. This interface does not refine the general contracts of theequals andhashCode methods. The result of testing two objectsthat implementCharSequence for equality is therefore, in general, undefined.Each object may be implemented by a different class, and thereis no guarantee that each class will be capable of testing its instancesfor equality with those of the other. It is therefore inappropriate to usearbitraryCharSequence instances as elements in a set or as keys ina map.
- Since:
- 1.4
Method Summary
Modifier and TypeMethodDescriptioncharcharAt(int index) Returns thecharvalue at the specified index.defaultIntStreamchars()Returns a stream ofintzero-extending thecharvaluesfrom this sequence.defaultIntStreamReturns a stream of code point values from this sequence.static intcompare(CharSequence cs1,CharSequence cs2) Compares twoCharSequenceinstances lexicographically.default voidgetChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) Copies characters from this sequence into the given destination array.default booleanisEmpty()Returnstrueif this character sequence is empty.intlength()Returns the length of this character sequence.subSequence(int start, int end) Returns aCharSequencethat is a subsequence of this sequence.toString()Returns a string containing the characters in this sequence in the sameorder as this sequence.
Method Details
length
int length()Returns the length of this character sequence. The length is the numberof 16-bitchars in the sequence.- Returns:
- the number of
chars in this sequence
charAt
char charAt(int index) Returns thecharvalue at the specified index. An index ranges from zerotolength() - 1. The firstcharvalue of the sequence is atindex zero, the next at index one, and so on, as for arrayindexing.If the
charvalue specified by the index is asurrogate, the surrogate valueis returned.- Parameters:
index- the index of thecharvalue to be returned- Returns:
- the specified
charvalue - Throws:
IndexOutOfBoundsException- if theindexargument is negative or not less thanlength()
isEmpty
default boolean isEmpty()Returnstrueif this character sequence is empty.- Implementation Requirements:
- The default implementation returns the result of calling
length() == 0. - Returns:
trueiflength()is0, otherwisefalse- Since:
- 15
subSequence
Returns aCharSequencethat is a subsequence of this sequence.The subsequence starts with thecharvalue at the specified index andends with thecharvalue at indexend - 1. The length(inchars) of thereturned sequence isend - start, so ifstart == endthen an empty sequence is returned.- Parameters:
start- the start index, inclusiveend- the end index, exclusive- Returns:
- the specified subsequence
- Throws:
IndexOutOfBoundsException- ifstartorendare negative, ifendis greater thanlength(), or ifstartis greater thanend
toString
chars
Returns a stream ofintzero-extending thecharvaluesfrom this sequence. Any char which maps to asurrogate code point is passedthrough uninterpreted.The stream binds to this sequence when the terminal stream operationcommences (specifically, for mutable sequences the spliterator for thestream islate-binding).If the sequence is modified during that operation then the result isundefined.
- Returns:
- an IntStream of char values from this sequence
- Since:
- 1.8
codePoints
Returns a stream of code point values from this sequence. Any surrogatepairs encountered in the sequence are combined as if byCharacter.toCodePoint and the result is passedto the stream. Any other code units, including ordinary BMP characters,unpaired surrogates, and undefined code units, are zero-extended tointvalues which are then passed to the stream.The stream binds to this sequence when the terminal stream operationcommences (specifically, for mutable sequences the spliterator for thestream islate-binding).If the sequence is modified during that operation then the result isundefined.
- Returns:
- an IntStream of Unicode code points from this sequence
- Since:
- 1.8
compare
Compares twoCharSequenceinstances lexicographically. Returns anegative value, zero, or a positive value if the first sequence is lexicographicallyless than, equal to, or greater than the second, respectively.The lexicographical ordering of
CharSequenceis defined as follows.Consider aCharSequencecs of lengthlen to be asequence of char values,cs[0] tocs[len-1]. Supposekis the lowest index at which the corresponding char values from each sequencediffer. The lexicographic ordering of the sequences is determined by a numericcomparison of the char valuescs1[k] withcs2[k]. If there isno such indexk, the shorter sequence is considered lexicographicallyless than the other. If the sequences have the same length, the sequences areconsidered lexicographically equal.- Parameters:
cs1- the firstCharSequencecs2- the secondCharSequence- Returns:
- the value
0if the twoCharSequenceare equal; a negative integer if the firstCharSequenceis lexicographically less than the second; or a positive integer if the firstCharSequenceis lexicographically greater than the second. - Since:
- 11
getChars
default void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) Copies characters from this sequence into the given destination array.The first character to be copied is at indexsrcBegin; the lastcharacter to be copied is at indexsrcEnd-1. The total number ofcharacters to be copied issrcEnd-srcBegin. Thecharacters are copied into the subarray ofdststartingat indexdstBeginand ending at index:dstbegin + (srcEnd-srcBegin) - 1- Implementation Requirements:
- The default implementation invokes
charAt(int index)in a loopiteratingindexfromsrcBegintosrcEnd-1.Concurrent truncation of this character sequence can throwIndexOutOfBoundsException. In this case, some characters, but notall, may be already transferred. - Parameters:
srcBegin- start copying at this offset.srcEnd- stop copying at this offset.dst- the array to copy the data into.dstBegin- offset intodst.- Throws:
IndexOutOfBoundsException- if any of the following is true:srcBeginis negativedstBeginis negative- the
srcBeginargument is greater than thesrcEndargument. srcEndis greater thanthis.length().dstBegin+srcEnd-srcBeginis greater thandst.length
NullPointerException- ifdstisnull- Since:
- 25