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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) 2013-2019 TU Dortmund
* This file is part of AutomataLib, http://www.automatalib.net/.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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.Graph;
import net.automatalib.visualization.DefaultVisualizationHelper;
import net.automatalib.visualization.VisualizationHelper;
public class SuffixTrie implements Graph, 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 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;
}
}
/**
* Internal constructor. Allows to override the root node.
*
* @param root
* the root node.
*/
protected SuffixTrie(SuffixTrieNode root) {
this(DEFAULT_GRAPH_REPRESENTABLE, root);
}
@Override
public Collection> getNodes() {
if (nodes == null) {
throw new UnsupportedOperationException("This trie is not graph representable");
}
return Collections.unmodifiableCollection(nodes);
}
@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);
}
@Override
public SuffixTrieNode getTarget(SuffixTrieNode edge) {
if (nodes == null) {
throw new UnsupportedOperationException("This trie is not graph representable");
}
return edge;
}
@Override
public VisualizationHelper, SuffixTrieNode> getVisualizationHelper() {
if (nodes == null) {
throw new UnsupportedOperationException("This trie is not graph representable");
}
return new DefaultVisualizationHelper, SuffixTrieNode>() {
@Override
public boolean getNodeProperties(SuffixTrieNode node, Map properties) {
if (!super.getNodeProperties(node, properties)) {
return false;
}
String lbl = node.isRoot() ? "ε" : String.valueOf(node.getSymbol());
properties.put(NodeAttrs.LABEL, lbl);
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;
}
}