eu.interedition.collatex.suffixtree.Cursor Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of collatex-core Show documentation
A Java library for collating textual sources, for example, to produce an apparatus.
There is a newer version: 1.7.1
package eu.interedition.collatex.suffixtree;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;

/**
 * @param 
 * @param 
 * @author Max Garfinkel
 */
public class Cursor> {

    private final SuffixTree tree;
    private Node node;
    private Edge edge;
    private int length;


    Cursor(SuffixTree tree) {
        this.tree = tree;
        node = tree.getRoot();
        edge = null;
        length = 0;
    }

    boolean proceedTo(T item) {
        if (edge == null) {
            Edge tmpEdge = node.getEdgeStarting(item);
            if (tmpEdge != null) {
                edge = tmpEdge;
                length = 1;
                return true;
            } else {
                return false;
            }
        } else if (edge.getLength() > length) {
            T nextItem = edge.getItemAt(length);
            if (nextItem != null && item.equals(nextItem)) {
                length++;
                return true;
            } else {
                return false;
            }
        } else {
            Node terminal = edge.getTerminal();
            if (terminal == null)
                return false;
            else {
                Edge tmpEdge = terminal.getEdgeStarting(item);
                if (tmpEdge != null) {
                    edge = tmpEdge;
                    length = 1;
                    node = terminal;
                    return true;
                } else {
                    return false;
                }
            }
        }
    }

    Collection> getSequenceTerminals() {
        if (edge == null) {
            return node.getSuffixTerminals();
        } else {
            if ((edge.getLength() - 1 == length && !edge.isTerminating())
                || (edge.getItemAt(length).getClass().equals(SequenceTerminal.class)) && !edge.isTerminating()) {
                Object seqTerminal = edge.getItemAt(length);
                @SuppressWarnings("unchecked")
                SequenceTerminal term = (SequenceTerminal) seqTerminal;
                Collection> collection = new HashSet>();
                collection.add(term);
                return collection;
            } else {
                Node terminal = edge.getTerminal();
                if (terminal == null)
                    return Collections.emptySet();
                else {
                    Collection> edges = terminal.getEdges();
                    Collection> returnCollection = new HashSet>();
                    for (Edge edge : edges) {
                        Object o = edge.getStartItem();
                        if (o.getClass().equals(SequenceTerminal.class)) {
                            @SuppressWarnings("unchecked")
                            SequenceTerminal returnTerminal = (SequenceTerminal) o;
                            returnCollection.add(returnTerminal);
                        }
                    }
                    return returnCollection;
                }
            }
        }
    }

    void returnToRoot() {
        node = tree.getRoot();
        edge = null;
        length = 0;
    }

}