org.apache.commons.lang.text
Class StrTokenizer

java.lang.Object
  org.apache.commons.lang.text.StrTokenizer

All Implemented Interfaces:

Cloneable, Iterator, ListIterator

public class StrTokenizer
extends Object
implements ListIterator, Cloneable

Tokenizes a string based based on delimiters (separators) and supporting quoting and ignored character concepts.

This class can split a String into many smaller strings. It aims to do a similar job to StringTokenizer, however it offers much more control and flexibility including implementing the ListIterator interface. By default, it is set up like StringTokenizer.

The input String is split into a number of tokens. Each token is separated from the next String by a delimiter. One or more delimiter characters must be specified.

Each token may be surrounded by quotes. The quote matcher specifies the quote character(s). A quote may be escaped within a quoted section by duplicating itself.

Between each token and the delimiter are potentially characters that need trimming. The trimmer matcher specifies these characters. One usage might be to trim whitespace characters.

At any point outside the quotes there might potentially be invalid characters. The ignored matcher specifies these characters to be removed. One usage might be to remove new line characters.

Empty tokens may be removed or returned as null.

 "a,b,c"         - Three tokens "a","b","c"   (comma delimiter)
 " a, b , c "    - Three tokens "a","b","c"   (default CSV processing trims whitespace)
 "a, ", b ,", c" - Three tokens "a, " , " b ", ", c" (quoted text untouched)
 

This tokenizer has the following properties and options:

Property	Type	Default
delim	CharSetMatcher	{ \t\n\r\f}
quote	NoneMatcher	{}
ignore	NoneMatcher	{}
emptyTokenAsNull	boolean	false
ignoreEmptyTokens	boolean	true

Since:

2.2

Version:

$Id: StrTokenizer.java 907631 2010-02-08 12:22:48Z sebb $

Author:

Apache Software Foundation, Matthew Inger, Gary D. Gregory

Constructor Summary

StrTokenizer()
Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer, but with no text to tokenize.

StrTokenizer(char[] input)
Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer.

StrTokenizer(char[] input, char delim)
Constructs a tokenizer splitting on the specified character.

StrTokenizer(char[] input, char delim, char quote)
Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.

StrTokenizer(char[] input, String delim)
Constructs a tokenizer splitting on the specified string.

StrTokenizer(char[] input, StrMatcher delim)
Constructs a tokenizer splitting using the specified delimiter matcher.

StrTokenizer(char[] input, StrMatcher delim, StrMatcher quote)
Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.

StrTokenizer(String input)
Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer.

StrTokenizer(String input, char delim)
Constructs a tokenizer splitting on the specified delimiter character.

StrTokenizer(String input, char delim, char quote)
Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.

StrTokenizer(String input, String delim)
Constructs a tokenizer splitting on the specified delimiter string.

StrTokenizer(String input, StrMatcher delim)
Constructs a tokenizer splitting using the specified delimiter matcher.

StrTokenizer(String input, StrMatcher delim, StrMatcher quote)
Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.

Method Summary

void	add(Object obj) Unsupported ListIterator operation.
Object	clone() Creates a new instance of this Tokenizer.
String	getContent() Gets the String content that the tokenizer is parsing.
static StrTokenizer	getCSVInstance() Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input.
static StrTokenizer	getCSVInstance(char[] input) Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input.
static StrTokenizer	getCSVInstance(String input) Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input.
StrMatcher	getDelimiterMatcher() Gets the field delimiter matcher.
StrMatcher	getIgnoredMatcher() Gets the ignored character matcher.
StrMatcher	getQuoteMatcher() Gets the quote matcher currently in use.
String[]	getTokenArray() Gets a copy of the full token list as an independent modifiable array.
List	getTokenList() Gets a copy of the full token list as an independent modifiable list.
StrMatcher	getTrimmerMatcher() Gets the trimmer character matcher.
static StrTokenizer	getTSVInstance() Gets a new tokenizer instance which parses Tab Separated Value strings.
static StrTokenizer	getTSVInstance(char[] input) Gets a new tokenizer instance which parses Tab Separated Value strings.
static StrTokenizer	getTSVInstance(String input) Gets a new tokenizer instance which parses Tab Separated Value strings.
boolean	hasNext() Checks whether there are any more tokens.
boolean	hasPrevious() Checks whether there are any previous tokens that can be iterated to.
boolean	isEmptyTokenAsNull() Gets whether the tokenizer currently returns empty tokens as null.
boolean	isIgnoreEmptyTokens() Gets whether the tokenizer currently ignores empty tokens.
Object	next() Gets the next token.
int	nextIndex() Gets the index of the next token to return.
String	nextToken() Gets the next token from the String.
Object	previous() Gets the token previous to the last returned token.
int	previousIndex() Gets the index of the previous token.
String	previousToken() Gets the previous token from the String.
void	remove() Unsupported ListIterator operation.
StrTokenizer	reset() Resets this tokenizer, forgetting all parsing and iteration already completed.
StrTokenizer	reset(char[] input) Reset this tokenizer, giving it a new input string to parse.
StrTokenizer	reset(String input) Reset this tokenizer, giving it a new input string to parse.
void	set(Object obj) Unsupported ListIterator operation.
StrTokenizer	setDelimiterChar(char delim) Sets the field delimiter character.
StrTokenizer	setDelimiterMatcher(StrMatcher delim) Sets the field delimiter matcher.
StrTokenizer	setDelimiterString(String delim) Sets the field delimiter string.
StrTokenizer	setEmptyTokenAsNull(boolean emptyAsNull) Sets whether the tokenizer should return empty tokens as null.
StrTokenizer	setIgnoredChar(char ignored) Set the character to ignore.
StrTokenizer	setIgnoredMatcher(StrMatcher ignored) Set the matcher for characters to ignore.
StrTokenizer	setIgnoreEmptyTokens(boolean ignoreEmptyTokens) Sets whether the tokenizer should ignore and not return empty tokens.
StrTokenizer	setQuoteChar(char quote) Sets the quote character to use.
StrTokenizer	setQuoteMatcher(StrMatcher quote) Set the quote matcher to use.
StrTokenizer	setTrimmerMatcher(StrMatcher trimmer) Sets the matcher for characters to trim.
int	size() Gets the number of tokens found in the String.
protected List	tokenize(char[] chars, int offset, int count) Internal method to performs the tokenization.
String	toString() Gets the String content that the tokenizer is parsing.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

StrTokenizer

public StrTokenizer()

Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer, but with no text to tokenize.

This constructor is normally used with reset(String).

StrTokenizer

public StrTokenizer(String input)

Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer.

Parameters:

input - the string which is to be parsed

StrTokenizer

public StrTokenizer(String input,
                    char delim)

Constructs a tokenizer splitting on the specified delimiter character.

Parameters:

input - the string which is to be parsed

delim - the field delimiter character

StrTokenizer

public StrTokenizer(String input,
                    String delim)

Constructs a tokenizer splitting on the specified delimiter string.

Parameters:

input - the string which is to be parsed

delim - the field delimiter string

StrTokenizer

public StrTokenizer(String input,
                    StrMatcher delim)

Constructs a tokenizer splitting using the specified delimiter matcher.

Parameters:

input - the string which is to be parsed

delim - the field delimiter matcher

StrTokenizer

public StrTokenizer(String input,
                    char delim,
                    char quote)

Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.

Parameters:

input - the string which is to be parsed

delim - the field delimiter character

quote - the field quoted string character

StrTokenizer

public StrTokenizer(String input,
                    StrMatcher delim,
                    StrMatcher quote)

Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.

Parameters:

input - the string which is to be parsed

delim - the field delimiter matcher

quote - the field quoted string matcher

StrTokenizer

public StrTokenizer(char[] input)

Constructs a tokenizer splitting on space, tab, newline and formfeed as per StringTokenizer.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

StrTokenizer

public StrTokenizer(char[] input,
                    char delim)

Constructs a tokenizer splitting on the specified character.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

delim - the field delimiter character

StrTokenizer

public StrTokenizer(char[] input,
                    String delim)

Constructs a tokenizer splitting on the specified string.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

delim - the field delimiter string

StrTokenizer

public StrTokenizer(char[] input,
                    StrMatcher delim)

Constructs a tokenizer splitting using the specified delimiter matcher.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

delim - the field delimiter matcher

StrTokenizer

public StrTokenizer(char[] input,
                    char delim,
                    char quote)

Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

delim - the field delimiter character

quote - the field quoted string character

StrTokenizer

public StrTokenizer(char[] input,
                    StrMatcher delim,
                    StrMatcher quote)

Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the string which is to be parsed, not cloned

delim - the field delimiter character

quote - the field quoted string character

Method Detail

getCSVInstance

public static StrTokenizer getCSVInstance()

Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

You must call a "reset" method to set the string which you want to parse.

Returns:

a new tokenizer instance which parses Comma Separated Value strings

getCSVInstance

public static StrTokenizer getCSVInstance(String input)

Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

Parameters:

input - the text to parse

Returns:

a new tokenizer instance which parses Comma Separated Value strings

getCSVInstance

public static StrTokenizer getCSVInstance(char[] input)

Gets a new tokenizer instance which parses Comma Separated Value strings initializing it with the given input. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

Parameters:

input - the text to parse

Returns:

a new tokenizer instance which parses Comma Separated Value strings

getTSVInstance

public static StrTokenizer getTSVInstance()

Gets a new tokenizer instance which parses Tab Separated Value strings. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

You must call a "reset" method to set the string which you want to parse.

Returns:

a new tokenizer instance which parses Tab Separated Value strings.

getTSVInstance

public static StrTokenizer getTSVInstance(String input)

Gets a new tokenizer instance which parses Tab Separated Value strings. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

Parameters:

input - the string to parse

Returns:

a new tokenizer instance which parses Tab Separated Value strings.

getTSVInstance

public static StrTokenizer getTSVInstance(char[] input)

Gets a new tokenizer instance which parses Tab Separated Value strings. The default for CSV processing will be trim whitespace from both ends (which can be overridden with the setTrimmer method).

Parameters:

input - the string to parse

Returns:

a new tokenizer instance which parses Tab Separated Value strings.

size

public int size()

Gets the number of tokens found in the String.

Returns:

the number of matched tokens

nextToken

public String nextToken()

Gets the next token from the String. Equivalent to next() except it returns null rather than throwing NoSuchElementException when no tokens remain.

Returns:

the next sequential token, or null when no more tokens are found

previousToken

public String previousToken()

Gets the previous token from the String.

Returns:

the previous sequential token, or null when no more tokens are found

getTokenArray

public String[] getTokenArray()

Gets a copy of the full token list as an independent modifiable array.

Returns:

the tokens as a String array

getTokenList

public List getTokenList()

Gets a copy of the full token list as an independent modifiable list.

Returns:

the tokens as a String array

reset

public StrTokenizer reset()

Resets this tokenizer, forgetting all parsing and iteration already completed.

This method allows the same tokenizer to be reused for the same String.

Returns:

this, to enable chaining

reset

public StrTokenizer reset(String input)

Reset this tokenizer, giving it a new input string to parse. In this manner you can re-use a tokenizer with the same settings on multiple input lines.

Parameters:

input - the new string to tokenize, null sets no text to parse

Returns:

this, to enable chaining

reset

public StrTokenizer reset(char[] input)

Reset this tokenizer, giving it a new input string to parse. In this manner you can re-use a tokenizer with the same settings on multiple input lines.

The input character array is not cloned, and must not be altered after passing in to this method.

Parameters:

input - the new character array to tokenize, not cloned, null sets no text to parse

Returns:

this, to enable chaining

hasNext

public boolean hasNext()

Checks whether there are any more tokens.

Specified by:

hasNext in interface Iterator

Specified by:

hasNext in interface ListIterator

Returns:

true if there are more tokens

next

public Object next()

Gets the next token.

Specified by:

next in interface Iterator

Specified by:

next in interface ListIterator

Returns:

the next String token

Throws:

NoSuchElementException - if there are no more elements

nextIndex

public int nextIndex()

Gets the index of the next token to return.

Specified by:

nextIndex in interface ListIterator

Returns:

the next token index

hasPrevious

public boolean hasPrevious()

Checks whether there are any previous tokens that can be iterated to.

Specified by:

hasPrevious in interface ListIterator

Returns:

true if there are previous tokens

previous

public Object previous()

Gets the token previous to the last returned token.

Specified by:

previous in interface ListIterator

Returns:

the previous token

previousIndex

public int previousIndex()

Gets the index of the previous token.

Specified by:

previousIndex in interface ListIterator

Returns:

the previous token index

remove

public void remove()

Unsupported ListIterator operation.

Specified by:

remove in interface Iterator

Specified by:

remove in interface ListIterator

Throws:

UnsupportedOperationException - always

set

public void set(Object obj)

Unsupported ListIterator operation.

Specified by:

set in interface ListIterator

Parameters:

obj - this parameter ignored.

Throws:

UnsupportedOperationException - always

add

public void add(Object obj)

Unsupported ListIterator operation.

Specified by:

add in interface ListIterator

Parameters:

obj - this parameter ignored.

Throws:

UnsupportedOperationException - always

tokenize

protected List tokenize(char[] chars,
                        int offset,
                        int count)

Internal method to performs the tokenization.

Most users of this class do not need to call this method. This method will be called automatically by other (public) methods when required.

This method exists to allow subclasses to add code before or after the tokenization. For example, a subclass could alter the character array, offset or count to be parsed, or call the tokenizer multiple times on multiple strings. It is also be possible to filter the results.

StrTokenizer will always pass a zero offset and a count equal to the length of the array to this method, however a subclass may pass other values, or even an entirely different array.

Parameters:

chars - the character array being tokenized, may be null

offset - the start position within the character array, must be valid

count - the number of characters to tokenize, must be valid

Returns:

the modifiable list of String tokens, unmodifiable if null array or zero count

getDelimiterMatcher

public StrMatcher getDelimiterMatcher()

Gets the field delimiter matcher.

Returns:

the delimiter matcher in use

setDelimiterMatcher

public StrTokenizer setDelimiterMatcher(StrMatcher delim)

Sets the field delimiter matcher.

The delimitier is used to separate one token from another.

Parameters:

delim - the delimiter matcher to use

Returns:

this, to enable chaining

setDelimiterChar

public StrTokenizer setDelimiterChar(char delim)

Sets the field delimiter character.

Parameters:

delim - the delimiter character to use

Returns:

this, to enable chaining

setDelimiterString

public StrTokenizer setDelimiterString(String delim)

Sets the field delimiter string.

Parameters:

delim - the delimiter string to use

Returns:

this, to enable chaining

getQuoteMatcher

public StrMatcher getQuoteMatcher()

Gets the quote matcher currently in use.

The quote character is used to wrap data between the tokens. This enables delimiters to be entered as data. The default value is '"' (double quote).

Returns:

the quote matcher in use

setQuoteMatcher

public StrTokenizer setQuoteMatcher(StrMatcher quote)

Set the quote matcher to use.

The quote character is used to wrap data between the tokens. This enables delimiters to be entered as data.

Parameters:

quote - the quote matcher to use, null ignored

Returns:

this, to enable chaining

setQuoteChar

public StrTokenizer setQuoteChar(char quote)

Sets the quote character to use.

The quote character is used to wrap data between the tokens. This enables delimiters to be entered as data.

Parameters:

quote - the quote character to use

Returns:

this, to enable chaining

getIgnoredMatcher

public StrMatcher getIgnoredMatcher()

Gets the ignored character matcher.

These characters are ignored when parsing the String, unless they are within a quoted region. The default value is not to ignore anything.

Returns:

the ignored matcher in use

setIgnoredMatcher

public StrTokenizer setIgnoredMatcher(StrMatcher ignored)

Set the matcher for characters to ignore.

These characters are ignored when parsing the String, unless they are within a quoted region.

Parameters:

ignored - the ignored matcher to use, null ignored

Returns:

this, to enable chaining

setIgnoredChar

public StrTokenizer setIgnoredChar(char ignored)

Set the character to ignore.

This character is ignored when parsing the String, unless it is within a quoted region.

Parameters:

ignored - the ignored character to use

Returns:

this, to enable chaining

getTrimmerMatcher

public StrMatcher getTrimmerMatcher()

Gets the trimmer character matcher.

These characters are trimmed off on each side of the delimiter until the token or quote is found. The default value is not to trim anything.

Returns:

the trimmer matcher in use

setTrimmerMatcher

public StrTokenizer setTrimmerMatcher(StrMatcher trimmer)

Sets the matcher for characters to trim.

These characters are trimmed off on each side of the delimiter until the token or quote is found.

Parameters:

trimmer - the trimmer matcher to use, null ignored

Returns:

this, to enable chaining

isEmptyTokenAsNull

public boolean isEmptyTokenAsNull()

Gets whether the tokenizer currently returns empty tokens as null. The default for this property is false.

Returns:

true if empty tokens are returned as null

setEmptyTokenAsNull

public StrTokenizer setEmptyTokenAsNull(boolean emptyAsNull)

Sets whether the tokenizer should return empty tokens as null. The default for this property is false.

Parameters:

emptyAsNull - whether empty tokens are returned as null

Returns:

this, to enable chaining

isIgnoreEmptyTokens

public boolean isIgnoreEmptyTokens()

Gets whether the tokenizer currently ignores empty tokens. The default for this property is true.

Returns:

true if empty tokens are not returned

setIgnoreEmptyTokens

public StrTokenizer setIgnoreEmptyTokens(boolean ignoreEmptyTokens)

Sets whether the tokenizer should ignore and not return empty tokens. The default for this property is true.

Parameters:

ignoreEmptyTokens - whether empty tokens are not returned

Returns:

this, to enable chaining

getContent

public String getContent()

Gets the String content that the tokenizer is parsing.

Returns:

the string content being parsed

clone

public Object clone()

Creates a new instance of this Tokenizer. The new instance is reset so that it will be at the start of the token list. If a CloneNotSupportedException is caught, return null.

Overrides:

clone in class Object

Returns:

a new instance of this Tokenizer which has been reset.

toString

public String toString()

Gets the String content that the tokenizer is parsing.

Overrides:

toString in class Object

Returns:

the string content being parsed