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This artifact provides various common utility operations for analyzing and manipulating
automata and graphs, such as traversal, minimization and copying.
/* Copyright (C) 2013 TU Dortmund
* This file is part of AutomataLib, http://www.automatalib.net/.
*
* AutomataLib is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 3.0 as published by the Free Software Foundation.
*
* AutomataLib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with AutomataLib; if not, see
* http://www.gnu.de/documents/lgpl.en.html.
*/
/**
*
*/
package net.automatalib.util.minimizer;
import java.util.ArrayList;
import java.util.List;
import net.automatalib.commons.smartcollections.BasicLinkedListEntry;
import net.automatalib.commons.smartcollections.ElementReference;
/**
* State record. Represents a state in the automaton model the minimizer
* operates on, and also keeps various other information that is relevant
* for the process.
*
* @author Malte Isberner
*
* @param original state class.
* @param original transition label class.
*/
final class State extends BasicLinkedListEntry,State> {
// The identifier of this state.
private final int id;
// The state in the original automaton.
private final S originalState;
// The list of incoming edges.
private final List> incoming
= new ArrayList>();
// The list of outgoing edges.
private final List> outgoing
= new ArrayList>();
// The block that contains this state.
private Block block;
// A reference to this state in the block's collection.
private ElementReference blockReference;
// Signals whether or not this state is a split point, i.e.,
// differs from the preceeding states in the final list.
private boolean splitPoint;
// The signature of the state, i.e., a sorted list of the (relevant)
// outgoing edge labels.
private List> signature
= new ArrayList>();
/**
* Constructor.
* @param id the state id.
* @param originalState the original state represented by this
* record.
*/
public State(int id, S originalState) {
this.id = id;
this.originalState = originalState;
}
/**
* Retrieves the state id.
* @return the state id.
*/
public int getId() {
return id;
}
/**
* Retrieves the original state represented by
* this record.
* @return the original state object.
*/
public S getOriginalState() {
return originalState;
}
/**
* Sets the block which contains this state.
* @param block the new block containing this state.
*/
public void setBlock(Block block) {
this.block = block;
}
/**
* Retrieves the block which contains this state.
* @return the block containing this state.
*/
public Block getBlock() {
return block;
}
/**
* Retrieves the list of incoming edges.
* @return the incoming edges.
*/
public List> getIncoming() {
return incoming;
}
/**
* Retrieves the list of outgoing edges.
* @return the outgoing edges.
*/
public List> getOutgoing() {
return outgoing;
}
/**
* Adds a new incoming edge.
* @param edge the incoming edge.
*/
public void addIncomingEdge(Edge edge) {
incoming.add(edge);
}
/**
* Adds a new outgoing edge.
* @param edge the outgoing edge.
*/
public void addOutgoingEdge(Edge edge) {
outgoing.add(edge);
}
/**
* Sets the split point property of this state.
* @param splitPoint whether or not this state is a split point.
*/
public void setSplitPoint(boolean splitPoint) {
this.splitPoint = splitPoint;
}
/**
* Retrieves the split point property of this state.
* @return true iff this state is a split point,
* false otherwise.
*/
public boolean isSplitPoint() {
return splitPoint;
}
/**
* Resets the information needed for a single split step associated
* with this state, i.e., the split point property and the signature.
*/
public void reset() {
splitPoint = false;
if(signature == null)
signature = new ArrayList>();
else
signature.clear();
}
/**
* Adds a transition label (letter) to this state's signature.
* @param letter the letter to add.
* @return true iff this was the first letter to be added
* to the signature, false otherwise.
*/
public boolean addToSignature(TransitionLabel letter) {
boolean first = signature.isEmpty();
signature.add(letter);
return first;
}
/**
* Retrieves the letter from the signature with the given index.
* If there is no such index (because the signature is shorter),
* null is returned.
*
* @param index the signature index.
* @return the respective letter of the signature, or null.
*/
public TransitionLabel getSignatureLetter(int index) {
if(index < signature.size())
return signature.get(index);
return null;
}
/**
* Sets the reference referencing this state in its block's collection.
* @param ref the reference.
*/
public void setBlockReference(ElementReference ref) {
this.blockReference = ref;
}
/**
* Retrieves the block reference.
* @return the reference.
*/
public ElementReference getBlockReference() {
return blockReference;
}
/**
* Retrieves the signature of this state.
* @return the signature.
*/
public List> getSignature() {
return signature;
}
/**
* Retrieves whether or not the block containing this state is a singleton,
* i.e., contains only this state.
* @return true if the containing block is a singleton,
* false otherwise.
*/
public boolean isSingletonBlock() {
return (block.size() == 1);
}
/*
* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return originalState.toString();
}
@Override
public State getElement() {
return this;
}
}