dfabuilder.State Class Reference

List of all members.

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Detailed Description

This class represents a single state in a DFA. It also hold all the transition rules that lead out of the state as well as information on the type of the state and its label.

Author:

Iain Robinson

Version:

1.0

Public Member Functions
	State (String name)
	State (String name, int type)
void	addRule (char character, State newState)
void	addRule (TokenSet set, State newState)
Hashtable	getRules ()
Vector	getSets ()
TokenSet	containsSymbolInSet (Character character)
Public Attributes
String	returnValue
String	returnType
int	type
String	name
Static Public Attributes
static final int	NORMAL_STATE = 0
static final int	GOAL_STATE = 1
Protected Member Functions
boolean	compute (String sym)

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Constructor & Destructor Documentation

dfabuilder.State.State (  String  name  )

Creates a new State object of a NORMAL_STATE type. Parameters: name  The name to be givenm to the state being created.

dfabuilder.State.State (  String  name, int  type )

Creates a new State object of a specific type - NORMAL_STATE or GOAL_STATE. Parameters: name  The name to be givenm to the state being created. type  The type of state to be created - use State.NORMAL_STATE or State.GOAL_STATE.

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Member Function Documentation

void dfabuilder.State.addRule (  TokenSet  set, State  newState )

This method creates a new rule stating that "if any character in 'a' is encountered then move to state 's'". Parameters: set  Array of characters triggering a transition to newState. newState  State to be moved to.

void dfabuilder.State.addRule (  char  character, State  newState )

This method creates a new rule stating that "if character 'c' is encountered then move to state 's'". Parameters: character  character triggering a transition to newState. newState  State to be moved to.

boolean dfabuilder.State.compute (  String  sym  )  [protected]

This method works out if a given character triggers a move to another state from this one. If this is possible it initiates a recursive algorithm by calling the same method in the new state. Parameters: sym  The string to be analysed. Returns: true if there is a transition triggered by the first character of string 'sym' - false if not. Because the method isrecursive the returned value indicates if the input string is valid according to the DFA.

TokenSet dfabuilder.State.containsSymbolInSet (  Character  character  )

Checks to see if the specified character is already contained within any TokenSet used by the state. Parameters: character  The character to be searched for. Returns: True if the character is found in a TokenSet, false if not.

Hashtable dfabuilder.State.getRules (   )

Returns a hashtable of all the transition rules for the state in the form Character->Next State. Returns: A Hashtable containing the transition rules of the state.

Vector dfabuilder.State.getSets (   )

Returns a vector of all the token groups that trigger transitions from this state. Returns: A vector of TokenSets.

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Member Data Documentation

final int dfabuilder.State.GOAL_STATE = 1 [static]

Constant indicating a goal type of state.

String dfabuilder.State.name

The name of the state. As a convention states in a DFA are labeled q0, q1... but this can be adjusted for any purpose.

final int dfabuilder.State.NORMAL_STATE = 0 [static]

Constant indicating a standard type of state.

String dfabuilder.State.returnType

The return type of the DFA. Can be an arbitrary string indicating the form of the data.

String dfabuilder.State.returnValue

If an input string matches the DFA this will hold the part of that string processed by the state.

int dfabuilder.State.type

The type of the state - can be GOAL_STATE or NORMAL_STATE.

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