DFA

java.lang.Object
- jflex.DFA

```
public final class DFA
extends java.lang.Object
```
Deterministic finite automata representation in JFlex. Contains minimization algorithm.

Version:

JFlex 1.7.0

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) Action[]`	`action` `action[state]` is the action that is to be carried out in state `state`, `null` if there is no action.
`(package private) int[]`	`entryState` entryState[i] is the start-state of lexical state i or lookahead DFA i
`(package private) boolean[]`	`isFinal` `isFinal[state] == true` <=> the state `state` is a final state.
`(package private) boolean`	`lookaheadUsed` True iff this DFA contains general lookahead
`static int`	`NO_TARGET` The code for "no target state" in the transition table.
`(package private) int`	`numInput` The current maximum number of input characters
`(package private) int`	`numLexStates` The number of lexical states (2*numLexStates <= entryState.length)
`(package private) int`	`numStates` The number of states in this DFA
`private static int`	`STATES` The initial number of states
`(package private) int[][]`	`table` table[current_state][character] is the next state for `current_state` with input `character`, `NO_TARGET` if there is no transition for this input in `current_state`
`(package private) java.util.Map<Action,Action>`	`usedActions` all actions that are used in this DFA

Constructor Summary

Constructors
Constructor and Description

DFA(int numEntryStates, int numInp, int numLexStates)
Constructor for a deterministic finite automata.

Constructors
Constructor and Description
`DFA(int numEntryStates, int numInp, int numLexStates)` Constructor for a deterministic finite automata.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addTransition(int start, int input, int dest)` addTransition.
`void`	`checkActions(LexScan scanner, LexParse parser)` Checks that all actions can actually be matched in this DFA.
`private java.lang.String`	`dotFormat()` Returns a gnu representation of the DFA.
`private void`	`ensureStateCapacity(int newNumStates)`
`void`	`minimize()` Implementation of Hopcroft's O(n log n) minimization algorithm, follows description by D.
`boolean[][]`	`old_minimize()` Much simpler, but slower and less memory efficient minimization algorithm.
`void`	`printBlocks(int[] b, int[] b_f, int[] b_b, int last)` printBlocks.
`void`	`printInvDelta(int[][] inv_delta, int[] inv_delta_set)` Prints the inverse of transition table.
`void`	`printL(int[] l_f, int[] l_b, int anchor)` printL.
`void`	`printTable(boolean[][] equiv)` Prints the equivalence table.
`void`	`setAction(int state, Action stateAction)` Sets the action.
`void`	`setEntryState(int eState, int trueState)` Sets the state of the entry.
`void`	`setFinal(int state, boolean isFinalState)` setFinal.
`java.lang.String`	`toString()` Returns a string representation of the DFA.
`java.lang.String`	`toString(int[] a)` Returns a representation of this DFA.
`(package private) void`	`writeDot(java.io.File file)` Writes a dot-file representing this DFA.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - STATES
```
private static final int STATES
```
    The initial number of states
    
    See Also:
    
    Constant Field Values
  - NO_TARGET
```
public static final int NO_TARGET
```
    The code for "no target state" in the transition table.
    
    See Also:
    
    Constant Field Values
  - table
```
int[][] table
```
    table[current_state][character] is the next state for current_state with input character, NO_TARGET if there is no transition for this input in current_state
  - isFinal
```
boolean[] isFinal
```
    isFinal[state] == true <=> the state state is a final state.
  - action
```
Action[] action
```
    action[state] is the action that is to be carried out in state state, null if there is no action.
  - entryState
```
int[] entryState
```
    entryState[i] is the start-state of lexical state i or lookahead DFA i
  - numStates
```
int numStates
```
    The number of states in this DFA
  - numInput
```
int numInput
```
    The current maximum number of input characters
  - numLexStates
```
int numLexStates
```
    The number of lexical states (2*numLexStates <= entryState.length)
  - usedActions
```
java.util.Map<Action,Action> usedActions
```
    all actions that are used in this DFA
  - lookaheadUsed
```
boolean lookaheadUsed
```
    True iff this DFA contains general lookahead
- Constructor Detail
  - DFA
```
public DFA(int numEntryStates,
           int numInp,
           int numLexStates)
```
    Constructor for a deterministic finite automata.
- Method Detail
  - setEntryState
```
public void setEntryState(int eState,
                          int trueState)
```
    Sets the state of the entry.
    
    Parameters:
    
    eState - entry state.
    
    trueState - whether it is the current state.
  - ensureStateCapacity
```
private void ensureStateCapacity(int newNumStates)
```
  - setAction
```
public void setAction(int state,
                      Action stateAction)
```
    Sets the action.
    
    Parameters:
    
    state - a int.
    
    stateAction - a Action object.
  - setFinal
```
public void setFinal(int state,
                     boolean isFinalState)
```
    setFinal.
    
    Parameters:
    
    state - a int.
    
    isFinalState - a boolean.
  - addTransition
```
public void addTransition(int start,
                          int input,
                          int dest)
```
    addTransition.
    
    Parameters:
    
    start - a int.
    
    input - a int.
    
    dest - a int.
  - toString
```
public java.lang.String toString()
```
    Returns a string representation of the DFA.
    
    Overrides:
    
    toString in class java.lang.Object
  - writeDot
```
void writeDot(java.io.File file)
```
    Writes a dot-file representing this DFA.
    
    Parameters:
    
    file - output file.
  - dotFormat
```
private java.lang.String dotFormat()
```
    Returns a gnu representation of the DFA.
    
    Returns:
    
    a representation in the dot format.
  - checkActions
```
public void checkActions(LexScan scanner,
                         LexParse parser)
```
    Checks that all actions can actually be matched in this DFA.
    
    Parameters:
    
    scanner - a LexScan.
    
    parser - a LexParse.
  - minimize
```
public void minimize()
```
    Implementation of Hopcroft's O(n log n) minimization algorithm, follows description by D. Gries.
    Time: O(n log n) Space: O(c n), size < 4*(5*c*n + 13*n + 3*c) byte
  - toString
```
public java.lang.String toString(int[] a)
```
    Returns a representation of this DFA.
    
    Parameters:
    
    a - an array of int.
    
    Returns:
    
    a String object.
  - printBlocks
```
public void printBlocks(int[] b,
                        int[] b_f,
                        int[] b_b,
                        int last)
```
    printBlocks.
    
    Parameters:
    
    b - an array of int.
    
    b_f - an array of int.
    
    b_b - an array of int.
    
    last - a int.
  - printL
```
public void printL(int[] l_f,
                   int[] l_b,
                   int anchor)
```
    printL.
    
    Parameters:
    
    l_f - an array of int.
    
    l_b - an array of int.
    
    anchor - a int.
  - old_minimize
```
public boolean[][] old_minimize()
```
    Much simpler, but slower and less memory efficient minimization algorithm.
    
    Returns:
    
    the equivalence relation on states.
  - printInvDelta
```
public void printInvDelta(int[][] inv_delta,
                          int[] inv_delta_set)
```
    Prints the inverse of transition table.
    
    Parameters:
    
    inv_delta - an array of int.
    
    inv_delta_set - an array of int.
  - printTable
```
public void printTable(boolean[][] equiv)
```
    Prints the equivalence table.
    
    Parameters:
    
    equiv - Equivalence table

Class DFA

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

STATES

NO_TARGET

table

isFinal

action

entryState

numStates

numInput

numLexStates

usedActions

lookaheadUsed

Constructor Detail

DFA

Method Detail

setEntryState

ensureStateCapacity

setAction

setFinal

addTransition

toString

writeDot

dotFormat

checkActions

minimize

toString

printBlocks

printL

old_minimize

printInvDelta

printTable