Package org.apache.commons.text

Class StringTokenizer

  • All Implemented Interfaces:
    java.lang.Cloneable, java.util.Iterator<java.lang.String>, java.util.ListIterator<java.lang.String>
    public class StringTokenizer
extends java.lang.Object
implements java.util.ListIterator<java.lang.String>, java.lang.Cloneable
    Tokenizes a string 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)
    StringTokenizer properties and options
    Property Type Default
    delim CharSetMatcher { \t\n\r\f}
    quote NoneMatcher {}
    ignore NoneMatcher {}
    emptyTokenAsNull boolean false
    ignoreEmptyTokens boolean true
    Since:
    1.3

    • Constructor Summary

      Constructors 
      Constructor Description
      StringTokenizer()
      Constructs a tokenizer splitting on space, tab, newline and form feed as per StringTokenizer, but with no text to tokenize.
      StringTokenizer​(char[] input)
      Constructs a tokenizer splitting on space, tab, newline and form feed as per StringTokenizer.
      StringTokenizer​(char[] input, char delim)
      Constructs a tokenizer splitting on the specified character.
      StringTokenizer​(char[] input, char delim, char quote)
      Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.
      StringTokenizer​(char[] input, java.lang.String delim)
      Constructs a tokenizer splitting on the specified string.
      StringTokenizer​(char[] input, StringMatcher delim)
      Constructs a tokenizer splitting using the specified delimiter matcher.
      StringTokenizer​(char[] input, StringMatcher delim, StringMatcher quote)
      Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.
      StringTokenizer​(java.lang.String input)
      Constructs a tokenizer splitting on space, tab, newline and form feed as per StringTokenizer.
      StringTokenizer​(java.lang.String input, char delim)
      Constructs a tokenizer splitting on the specified delimiter character.
      StringTokenizer​(java.lang.String input, char delim, char quote)
      Constructs a tokenizer splitting on the specified delimiter character and handling quotes using the specified quote character.
      StringTokenizer​(java.lang.String input, java.lang.String delim)
      Constructs a tokenizer splitting on the specified delimiter string.
      StringTokenizer​(java.lang.String input, StringMatcher delim)
      Constructs a tokenizer splitting using the specified delimiter matcher.
      StringTokenizer​(java.lang.String input, StringMatcher delim, StringMatcher quote)
      Constructs a tokenizer splitting using the specified delimiter matcher and handling quotes using the specified quote matcher.

    • Constructor Detail

      • StringTokenizer

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

        This constructor is normally used with reset(String).

      • StringTokenizer

        public StringTokenizer​(java.lang.String input)
        Constructs a tokenizer splitting on space, tab, newline and form feed as per StringTokenizer.
        Parameters:
        input - the string which is to be parsed

      • StringTokenizer

        public StringTokenizer​(java.lang.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

      • StringTokenizer

        public StringTokenizer​(java.lang.String input,
                       java.lang.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

      • StringTokenizer

        public StringTokenizer​(java.lang.String input,
                       StringMatcher delim)
        Constructs a tokenizer splitting using the specified delimiter matcher.
        Parameters:
        input - the string which is to be parsed
        delim - the field delimiter matcher

      • StringTokenizer

        public StringTokenizer​(java.lang.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

      • StringTokenizer

        public StringTokenizer​(java.lang.String input,
                       StringMatcher delim,
                       StringMatcher 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

      • StringTokenizer

        public StringTokenizer​(char[] input)
        Constructs a tokenizer splitting on space, tab, newline and form feed as per StringTokenizer.
        Parameters:
        input - the string which is to be parsed, not cloned

      • StringTokenizer

        public StringTokenizer​(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

      • StringTokenizer

        public StringTokenizer​(char[] input,
                       java.lang.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

      • StringTokenizer

        public StringTokenizer​(char[] input,
                       StringMatcher 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

      • StringTokenizer

        public StringTokenizer​(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

      • StringTokenizer

        public StringTokenizer​(char[] input,
                       StringMatcher delim,
                       StringMatcher 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 StringTokenizer 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 StringTokenizer getCSVInstance​(java.lang.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 StringTokenizer 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 StringTokenizer 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 StringTokenizer getTSVInstance​(java.lang.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 StringTokenizer 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 java.lang.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 java.lang.String previousToken()
        Gets the previous token from the String.
        Returns:
        The previous sequential token, or null when no more tokens are found

      • getTokenArray

        public java.lang.String[] getTokenArray()
        Gets a copy of the full token list as an independent modifiable array.
        Returns:
        The tokens as a String array

      • getTokenList

        public java.util.List<java.lang.String> getTokenList()
        Gets a copy of the full token list as an independent modifiable list.
        Returns:
        The tokens as a String array

      • reset

        public StringTokenizer 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 StringTokenizer reset​(java.lang.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 StringTokenizer 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 java.util.Iterator<java.lang.String>
        Specified by:
        hasNext in interface java.util.ListIterator<java.lang.String>
        Returns:
        true if there are more tokens

      • next

        public java.lang.String next()
        Gets the next token.
        Specified by:
        next in interface java.util.Iterator<java.lang.String>
        Specified by:
        next in interface java.util.ListIterator<java.lang.String>
        Returns:
        The next String token
        Throws:
        java.util.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 java.util.ListIterator<java.lang.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 java.util.ListIterator<java.lang.String>
        Returns:
        true if there are previous tokens

      • previous

        public java.lang.String previous()
        Gets the token previous to the last returned token.
        Specified by:
        previous in interface java.util.ListIterator<java.lang.String>
        Returns:
        The previous token

      • previousIndex

        public int previousIndex()
        Gets the index of the previous token.
        Specified by:
        previousIndex in interface java.util.ListIterator<java.lang.String>
        Returns:
        The previous token index

      • remove

        public void remove()
        Unsupported ListIterator operation.
        Specified by:
        remove in interface java.util.Iterator<java.lang.String>
        Specified by:
        remove in interface java.util.ListIterator<java.lang.String>
        Throws:
        java.lang.UnsupportedOperationException - always

      • set

        public void set​(java.lang.String obj)
        Unsupported ListIterator operation.
        Specified by:
        set in interface java.util.ListIterator<java.lang.String>
        Parameters:
        obj - this parameter ignored.
        Throws:
        java.lang.UnsupportedOperationException - always

      • add

        public void add​(java.lang.String obj)
        Unsupported ListIterator operation.
        Specified by:
        add in interface java.util.ListIterator<java.lang.String>
        Parameters:
        obj - this parameter ignored.
        Throws:
        java.lang.UnsupportedOperationException - always

      • getDelimiterMatcher

        public StringMatcher getDelimiterMatcher()
        Gets the field delimiter matcher.
        Returns:
        The delimiter matcher in use

      • setDelimiterMatcher

        public StringTokenizer setDelimiterMatcher​(StringMatcher delim)
        Sets the field delimiter matcher.

        The delimiter is used to separate one token from another.

        Parameters:
        delim - the delimiter matcher to use
        Returns:
        this, to enable chaining

      • setDelimiterChar

        public StringTokenizer setDelimiterChar​(char delim)
        Sets the field delimiter character.
        Parameters:
        delim - the delimiter character to use
        Returns:
        this, to enable chaining

      • setDelimiterString

        public StringTokenizer setDelimiterString​(java.lang.String delim)
        Sets the field delimiter string.
        Parameters:
        delim - the delimiter string to use
        Returns:
        this, to enable chaining

      • getQuoteMatcher

        public StringMatcher 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 StringTokenizer setQuoteMatcher​(StringMatcher 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 StringTokenizer 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 StringMatcher 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 StringTokenizer setIgnoredMatcher​(StringMatcher 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 StringTokenizer 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 StringMatcher 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 StringTokenizer setTrimmerMatcher​(StringMatcher 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 StringTokenizer 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 StringTokenizer 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 java.lang.String getContent()
        Gets the String content that the tokenizer is parsing.
        Returns:
        The string content being parsed

      • clone

        public java.lang.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.
        Returns:
        a new instance of this Tokenizer which has been reset.

      • toString

        public java.lang.String toString()
        Gets the String content that the tokenizer is parsing.
        Overrides:
        toString in class java.lang.Object
        Returns:
        The string content being parsed