gate.fsm
Class FSM

java.lang.Object
  gate.fsm.FSM

All Implemented Interfaces:

JapeConstants, Serializable

public class FSM
extends Object
implements JapeConstants

This class implements a standard Finite State Machine. It is used for both deterministic and non-deterministic machines.

See Also:

Serialized Form

Field Summary

private Collection	allStates The set of states for this FSM
(package private) int	bpeId
protected State	currentState Two members used by forEachState().
protected Transition	currentTransition
private static boolean	DEBUG Debug flag
private Set<AbstractSet>	dStates
protected State	finalState The final state of this FSM (usually only valid during construction).
private State	initialState The initial state of this FSM.
private Map<AbstractSet,State>	newStates
HashMap<String,String>	ruleHash
private ArrayList<RuleTime>	ruleTimes

Fields inherited from interface gate.jape.JapeConstants

ALL_STYLE, APPELT_STYLE, BRILL_STYLE, DEFAULT_PRIORITY, FIRST_STYLE, INDENT_PADDING, KLEENE_PLUS, KLEENE_QUERY, KLEENE_STAR, MULTI_SPAN_BINDING, NO_BINDING, NO_KLEENE_OP, ONCE_STYLE, SINGLE_SPAN_BINDING

Constructor Summary

protected	FSM() The constructor that all the other constructors should call.
protected	FSM(ComplexPatternElement cpe) Builds a FSM starting from a ComplexPatternElement.
	FSM(Rule rule) Builds a FSM starting from a rule.
	FSM(SinglePhaseTransducer spt) Builds a standalone FSM starting from a single phase transducer.

Method Summary

protected void	addRules(PrioritisedRuleList rules) Do the work involved in creating an FSM from a PrioritisedRuleList.
String	asGraphViz(boolean includeConstraints) Returns a representation of this FSM in the GraphViz graph-visualization language.
private State	convertComplexPE(State startState, ComplexPatternElement cpe, LinkedList<String> labels) Receives a state to start from and a complex pattern element.
private String	currentBasicBinding(BasicPatternElement bpe)
private String	currentBinding(ComplexPatternElement cpe, int indent)
private String	currentLHSBinding(LeftHandSide lhs)
private void	decorateStates()
void	eliminateVoidTransitions() Converts this FSM from a non-deterministic to a deterministic one by eliminating all the unrestricted transitions.
(package private) String	encodeForGraphViz(Map<String,String> m) Given a Map, encodes its keys and values as strings suitable for use as a GraphViz label.
protected void	forEachState(Runnable r) Iterates over all the states in this FSM, setting currentState and currentTransition, then calling the given Runnable callback.
private State	generateStates(State startState, ComplexPatternElement cpe, LinkedList<String> labels) Receives a state to start from and a complex pattern element.
Map<State,SimpleArraySet<Transition>>	getAllStates()
String	getGML() Returns a GML (Graph Modelling Language) representation of the transition graph of this FSM.
State	getInitialState() Gets the initial state of this FSM
ArrayList<RuleTime>	getRuleTimes()
private AbstractSet<State>	lambdaClosure(AbstractSet<State> s)
protected void	setRule(Rule rule) Do the work involved in creating an FSM from a Rule.
protected FSM	spawn(ComplexPatternElement currentPattern) A factory method for new FSMs like this one, given a ComplexPatternElement object.
protected FSM	spawn(Rule r) A factory method for new FSMs like this one, given a Rule object.
String	toString() Returns a textual description of this FSM.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ruleTimes

private ArrayList<RuleTime> ruleTimes

DEBUG

private static final boolean DEBUG

Debug flag

See Also:

Constant Field Values

currentState

protected State currentState

Two members used by forEachState().

currentTransition

protected Transition currentTransition

initialState

private State initialState

The initial state of this FSM.

finalState

protected State finalState

The final state of this FSM (usually only valid during construction).

allStates

private transient Collection allStates

The set of states for this FSM

newStates

private transient Map<AbstractSet,State> newStates

dStates

private transient Set<AbstractSet> dStates

bpeId

int bpeId

ruleHash

public HashMap<String,String> ruleHash

Constructor Detail

FSM

protected FSM()

The constructor that all the other constructors should call.

FSM

public FSM(SinglePhaseTransducer spt)

Builds a standalone FSM starting from a single phase transducer.

Parameters:

spt - the single phase transducer to be used for building this FSM.

FSM

public FSM(Rule rule)

Builds a FSM starting from a rule. This FSM is actually a part of a larger one (usually the one that is built based on the single phase transducer that contains the rule). built by this constructor.

Parameters:

rule - the rule to be used for the building process.

FSM

protected FSM(ComplexPatternElement cpe)

Builds a FSM starting from a ComplexPatternElement. This FSM is usually part of a larger FSM based on the Rule that contains the ComplexPatternElement.

Parameters:

cpe - the ComplexPatternElement to be used for the building process.

Method Detail

getRuleTimes

public ArrayList<RuleTime> getRuleTimes()

decorateStates

private void decorateStates()

addRules

protected void addRules(PrioritisedRuleList rules)

Do the work involved in creating an FSM from a PrioritisedRuleList.

setRule

protected void setRule(Rule rule)

Do the work involved in creating an FSM from a Rule.

spawn

protected FSM spawn(Rule r)

A factory method for new FSMs like this one, given a Rule object.

spawn

protected FSM spawn(ComplexPatternElement currentPattern)

A factory method for new FSMs like this one, given a ComplexPatternElement object.

getInitialState

public State getInitialState()

Gets the initial state of this FSM

Returns:

an object of type gate.fsm.State representing the initial state.

convertComplexPE

private State convertComplexPE(State startState,
                               ComplexPatternElement cpe,
                               LinkedList<String> labels)

Receives a state to start from and a complex pattern element. Parses the complex pattern element and creates all the necessary states and transitions for accepting annotations described by the given PE.

Parameters:

startState - the state to start from

cpe - the pattern to be recognized

labels - the bindings name for all the annotation accepted along the way. This is actually a list of Strings. It is necessary to use a list because of the recursive definition of ComplexPatternElement.

Returns:

the final state reached after accepting a sequence of annotations as described in the pattern

generateStates

private State generateStates(State startState,
                             ComplexPatternElement cpe,
                             LinkedList<String> labels)

Receives a state to start from and a complex pattern element. Parses the complex pattern element and creates all the necessary states and transitions for traversing the annotations described by the given PE exactly once. Does not add any transitions for kleene operators.

Parameters:

startState - the state to start from

cpe - the pattern to be recognized

labels - the bindings name for all the annotation accepted along the way. This is actually a list of Strings. It is necessary to use a list because of the recursive definition of ComplexPatternElement.

Returns:

the final state reached after accepting a sequence of annotations as described in the pattern

eliminateVoidTransitions

public void eliminateVoidTransitions()

Converts this FSM from a non-deterministic to a deterministic one by eliminating all the unrestricted transitions.

lambdaClosure

private AbstractSet<State> lambdaClosure(AbstractSet<State> s)

forEachState

protected void forEachState(Runnable r)

Iterates over all the states in this FSM, setting currentState and currentTransition, then calling the given Runnable callback.

getAllStates

public Map<State,SimpleArraySet<Transition>> getAllStates()

Returns:

a Map whose keys contain the states of this FSM, and whose values contain their corresponding transitions. This method actually walks the FSM, so it may be called before the FSM is finalized with compactTransitions().

asGraphViz

public String asGraphViz(boolean includeConstraints)

Returns a representation of this FSM in the GraphViz graph-visualization language. We use the "digraph" (directed graph) format. Nodes are labeled by their numerical indexes. A node's shape is a diamond if it's the initial state, and round otherwise. A node is green if it's an initial state, red if it's a final state, and black otherwise. Final states are also marked with a double-line outline.

Parameters:

includeConstraints - whether to include a stringified representation of each transition object as part of its label. The default is false.

Returns:

See Also:

the GraphViz web site for software to translate the output of this method into pretty pictures.

encodeForGraphViz

String encodeForGraphViz(Map<String,String> m)

Given a Map, encodes its keys and values as strings suitable for use as a GraphViz label. Embedded "\r\n" sequences are replaced by "\\l" to create line feeds, and embedded backslashes are escaped. The returned String takes the form "key1=value1, key2=value2, ...".

getGML

public String getGML()

Returns a GML (Graph Modelling Language) representation of the transition graph of this FSM.

toString

public String toString()

Returns a textual description of this FSM.

Overrides:

toString in class Object

currentBinding

private String currentBinding(ComplexPatternElement cpe,
                              int indent)

currentBasicBinding

private String currentBasicBinding(BasicPatternElement bpe)

currentLHSBinding

private String currentLHSBinding(LeftHandSide lhs)