public class Automaton extends Object implements Accountable
createState()
. Mark a
state as an accept state using setAccept(int, boolean)
. Add transitions
using addTransition(int, int, int)
. Each state must have all of its
transitions added at once; if this is too restrictive then use
Automaton.Builder
instead. State 0 is always the
initial state. Once a state is finished, either
because you've starting adding transitions to another state or you
call finishState()
, then that states transitions are sorted
(first by min, then max, then dest) and reduced (transitions with
adjacent labels going to the same dest are combined).Modifier and Type | Class and Description |
---|---|
static class |
Automaton.Builder
Records new states and transitions and then
Automaton.Builder.finish() creates the Automaton . |
NULL_ACCOUNTABLE
Constructor and Description |
---|
Automaton()
Sole constructor; creates an automaton with no states.
|
Automaton(int numStates,
int numTransitions)
Constructor which creates an automaton with enough space for the given
number of states and transitions.
|
Modifier and Type | Method and Description |
---|---|
void |
addEpsilon(int source,
int dest)
Add a [virtual] epsilon transition between source and dest.
|
void |
addTransition(int source,
int dest,
int label)
Add a new transition with min = max = label.
|
void |
addTransition(int source,
int dest,
int min,
int max)
Add a new transition with the specified source, dest, min, max.
|
void |
copy(Automaton other)
Copies over all states/transitions from other.
|
int |
createState()
Create a new state.
|
void |
finishState()
Finishes the current state; call this once you are done adding
transitions for a state.
|
void |
getNextTransition(Transition t)
Iterate to the next transition after the provided one
|
int |
getNumStates()
How many states this automaton has.
|
int |
getNumTransitions()
How many transitions this automaton has.
|
int |
getNumTransitions(int state)
How many transitions this state has.
|
Transition[][] |
getSortedTransitions()
Sugar to get all transitions for all states.
|
void |
getTransition(int state,
int index,
Transition t)
Fill the provided
Transition with the index'th
transition leaving the specified state. |
int |
initTransition(int state,
Transition t)
Initialize the provided Transition to iterate through all transitions
leaving the specified state.
|
boolean |
isAccept(int state)
Returns true if this state is an accept state.
|
boolean |
isDeterministic()
Returns true if this automaton is deterministic (for ever state
there is only one transition for each label).
|
int |
next(Transition transition,
int label)
Looks for the next transition that matches the provided label, assuming determinism.
|
long |
ramBytesUsed()
Return the memory usage of this object in bytes.
|
void |
setAccept(int state,
boolean accept)
Set or clear this state as an accept state.
|
int |
step(int state,
int label)
Performs lookup in transitions, assuming determinism.
|
String |
toDot()
Returns the dot (graphviz) representation of this automaton.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
getChildResources
public Automaton()
public Automaton(int numStates, int numTransitions)
numStates
- Number of states.numTransitions
- Number of transitions.public int createState()
public void setAccept(int state, boolean accept)
public Transition[][] getSortedTransitions()
public boolean isAccept(int state)
public void addTransition(int source, int dest, int label)
public void addTransition(int source, int dest, int min, int max)
public void addEpsilon(int source, int dest)
public void copy(Automaton other)
public boolean isDeterministic()
public void finishState()
public int getNumStates()
public int getNumTransitions()
public int getNumTransitions(int state)
public int initTransition(int state, Transition t)
getNextTransition(org.apache.lucene.util.automaton.Transition)
to
get each transition. Returns the number of transitions
leaving this state.public void getNextTransition(Transition t)
public void getTransition(int state, int index, Transition t)
Transition
with the index'th
transition leaving the specified state.public String toDot()
public int step(int state, int label)
state
- starting statelabel
- codepoint to look uppublic int next(Transition transition, int label)
This method is similar to step(int, int)
but is used more efficiently
when iterating over multiple transitions from the same source state. It keeps
the latest reached transition index in transition.transitionUpto
so
the next call to this method can continue from there instead of restarting
from the first transition.
transition
- The transition to start the lookup from (inclusive, using its
Transition.source
and Transition.transitionUpto
).
It is updated with the matched transition;
or with Transition.dest
= -1 if no match.label
- The codepoint to look up.public long ramBytesUsed()
Accountable
ramBytesUsed
in interface Accountable
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