Class 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:

    PropertyTypeDefault
    delimCharSetMatcher{ \t\n\r\f}
    quoteNoneMatcher{}
    ignoreNoneMatcher{}
    emptyTokenAsNullbooleanfalse
    ignoreEmptyTokensbooleantrue
    Since:
    2.2
    Version:
    $Id: StrTokenizer.java 907631 2010-02-08 12:22:48Z sebb $
    • 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
      • 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
      • 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