net.automatalib.util.tries.SuffixTrie Maven / Gradle / Ivy
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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.tries;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import net.automatalib.graphs.abstractimpl.AbstractGraph;
import net.automatalib.graphs.dot.DOTPlottableGraph;
import net.automatalib.graphs.dot.EmptyDOTHelper;
import net.automatalib.graphs.dot.GraphDOTHelper;
public class SuffixTrie extends AbstractGraph,SuffixTrieNode> implements DOTPlottableGraph,SuffixTrieNode> {
public static final boolean DEFAULT_GRAPH_REPRESENTABLE = true;
protected final SuffixTrieNode root;
protected final List> nodes;
/**
* Constructor. Constructs a graph-representable suffix trie.
*/
public SuffixTrie() {
this(DEFAULT_GRAPH_REPRESENTABLE);
}
/**
* Constructor. Constructs a suffix trie.
* @param graphRepresentable whether the trie should be graph representable.
*/
public SuffixTrie(boolean graphRepresentable) {
this(graphRepresentable, new SuffixTrieNode());
}
/**
* Internal constructor. Allows to override the root node.
* @param root the root node.
*/
protected SuffixTrie(SuffixTrieNode root) {
this(DEFAULT_GRAPH_REPRESENTABLE, root);
}
/**
* Internal constructor. Allows to override the root node
* and graph representability.
* @param graphRepresentable whether the trie should be graph representable.
* @param root the root node.
*/
protected SuffixTrie(boolean graphRepresentable, SuffixTrieNode root) {
this.root = root;
if(graphRepresentable) {
this.nodes = new ArrayList<>();
this.nodes.add(root);
}
else {
this.nodes = null;
}
}
/*
* (non-Javadoc)
* @see net.automatalib.graphs.Graph#getNodes()
*/
@Override
public Collection> getNodes() {
if(nodes == null)
throw new UnsupportedOperationException("This trie is not graph representable");
return Collections.unmodifiableCollection(nodes);
}
/*
* (non-Javadoc)
* @see net.automatalib.graphs.IndefiniteGraph#getOutgoingEdges(java.lang.Object)
*/
@Override
public Collection> getOutgoingEdges(SuffixTrieNode node) {
if(nodes == null)
throw new UnsupportedOperationException("This trie is not graph representable");
SuffixTrieNode parent = node.getParent();
if(parent == null)
return Collections.emptySet();
return Collections.singleton(parent);
}
/*
* (non-Javadoc)
* @see net.automatalib.graphs.IndefiniteGraph#getTarget(java.lang.Object)
*/
@Override
public SuffixTrieNode getTarget(SuffixTrieNode edge) {
if(nodes == null)
throw new UnsupportedOperationException("This trie is not graph representable");
return edge;
}
/*
* (non-Javadoc)
* @see net.automatalib.graphs.dot.DOTPlottableGraph#getGraphDOTHelper()
*/
@Override
public GraphDOTHelper, SuffixTrieNode> getGraphDOTHelper() {
if(nodes == null)
throw new UnsupportedOperationException("This trie is not graph representable");
return new EmptyDOTHelper,SuffixTrieNode>() {
/* (non-Javadoc)
* @see net.automatalib.graphs.dot.DefaultDOTHelper#getNodeProperties(java.lang.Object, java.util.Map)
*/
@Override
public boolean getNodeProperties(SuffixTrieNode node,
Map properties) {
if(!super.getNodeProperties(node, properties))
return false;
if(node.isRoot())
properties.put(LABEL, "ε");
else
properties.put(LABEL, String.valueOf(node.getSymbol()));
return true;
}
};
}
/**
* Adds a word to the trie.
* @param symbol the first symbol of the word.
* @param parent the remaining suffix of the word.
* @return a trie node corresponding to the inserted word.
*/
public SuffixTrieNode add(I symbol, SuffixTrieNode parent) {
SuffixTrieNode n = new SuffixTrieNode<>(symbol, parent);
if(nodes != null) {
nodes.add(n);
}
return n;
}
/**
* Returns the root of this trie.
* @return the root of this trie.
*/
public SuffixTrieNode getRoot() {
return root;
}
}