org.apache.commons.lang3.text

## Class StrTokenizer

- java.lang.Object
- - org.apache.commons.lang3.text.StrTokenizer

- All Implemented Interfaces:
    Cloneable, Iterator<String>, ListIterator<String>

      public class StrTokenizer
      extends Object
      implements ListIterator<String>, 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 1583482 2014-03-31 22:54:57Z niallp $

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `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

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `add(String 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<String>` | `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.
    `String` | `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.
    `String` | `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(String 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<String>` | `tokenize(char[] srcChars, 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.
      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.
      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.
      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.
      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.
      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.
      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<String> 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.
      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<String>`
      Specified by:
        `hasNext` in interface `ListIterator<String>`
      Returns:
        true if there are more tokens

    - #### next

          public String next()

      Gets the next token.
      Specified by:
        `next` in interface `Iterator<String>`
      Specified by:
        `next` in interface `ListIterator<String>`
      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<String>`
      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<String>`
      Returns:
        true if there are previous tokens

    - #### previous

          public String previous()

      Gets the token previous to the last returned token.
      Specified by:
        `previous` in interface `ListIterator<String>`
      Returns:
        the previous token

    - #### previousIndex

          public int previousIndex()

      Gets the index of the previous token.
      Specified by:
        `previousIndex` in interface `ListIterator<String>`
      Returns:
        the previous token index

    - #### remove

          public void remove()

      Unsupported ListIterator operation.
      Specified by:
        `remove` in interface `Iterator<String>`
      Specified by:
        `remove` in interface `ListIterator<String>`
      Throws:
        `UnsupportedOperationException` - always

    - #### set

          public void set(String obj)

      Unsupported ListIterator operation.
      Specified by:
        `set` in interface `ListIterator<String>`
      Parameters:
        `obj` - this parameter ignored.
      Throws:
        `UnsupportedOperationException` - always

    - #### add

          public void add(String obj)

      Unsupported ListIterator operation.
      Specified by:
        `add` in interface `ListIterator<String>`
      Parameters:
        `obj` - this parameter ignored.
      Throws:
        `UnsupportedOperationException` - always

    - #### tokenize

          protected List<String> tokenize(char[] srcChars,
                              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:
        `srcChars` - 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

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