Interface ITokenizer

A tokenizer divides a string into tokens. This class is highly customizable with regard to exactly how this division occurs, but it also has defaults that are suitable for many languages. This class assumes that the character values read from the string lie in the range 0-255. For example, the Unicode value of a capital A is 65, so System.out.println((char)65); prints out a capital A.

The behavior of a tokenizer depends on its character state table. This table is an array of 256 TokenizerState states. The state table decides which state to enter upon reading a character from the input string.

For example, by default, upon reading an 'A', a tokenizer will enter a "word" state. This means the tokenizer will ask a WordState object to consume the 'A', along with the characters after the 'A' that form a word. The state's responsibility is to consume characters and return a complete token.

The default table sets a SymbolState for every character from 0 to 255, and then overrides this with:

From    To     State
0     ' '    whitespaceState
'a'    'z'    wordState
'A'    'Z'    wordState
160     255    wordState
'0'    '9'    numberState
'-'    '-'    numberState
'.'    '.'    numberState
'"'    '"'    quoteState
'\''   '\''    quoteState
'/'    '/'    slashState

In addition to allowing modification of the state table, this class makes each of the states above available. Some of these states are customizable. For example, wordState allows customization of what characters can be part of a word, after the first character.