/*
 * [GoList.java]
 *
 * Summary: Data for a go to List of URLs sorted by humanname.
 *
 * Copyright: (c) 2001-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2001-03-08 initial
 *  1.1 2006-01-01
 *  1.2 2006-03-05 reformat with IntelliJ, add Javadoc
 */
package com.mindprod.go;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.Serializable;

/**
 * Data for a go to List of URLs sorted by humanname.
 * <p/>
 * Originally worked even under JDK 1.1, thus no ArrayLists.
 * Even though we no longer display the index in an Applet, SeeSort uses the index to patch links.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.2 2006-03-05 reformat with IntelliJ, add Javadoc
 * @since 2001-03-08
 */
public final class GoList implements Serializable
    {
    /**
     * version number for the class
     */
    static final long serialVersionUID = 1L;

    /**
     * list of the webroot-relative filenames of the places to jump to. Three separate arrays is more RAM efficient
     * than a single array to a triple
     * e.g. jgloss/certificate.html
     */
    private final String[] filenames;

    /**
     * list of human names for the places to jump to e.g. "updating certificate roots"
     */
    private final String[] humannames;

    /**
     * list of target parts of the URL to jump to e.g. ROOT
     */
    private final String[] targets;

    /**
     * how many elements we have added so far
     */
    private int size = 0;

    /**
     * @param size How many elements in the list.
     */
    public GoList( int size )
        {
        filenames = new String[ size ];
        targets = new String[ size ];
        humannames = new String[ size ];
        }

    /**
     * Read a previously serialised Golist. Corresponding Write is part of com.mindprod.qf.BuildIndexes.
     *
     * @param is InputStream (not ObjectInputStream) to read the golist from.
     *
     * @return GoList object from serialised object in file
     * @throws IOException            if cannot fetch the gotlist resource
     * @throws ClassNotFoundException if stream contains unknown classes.
     */
    public static GoList getData( InputStream is ) throws IOException, ClassNotFoundException
        {
        // O P E N
        // look in jar, on classpath, locally or server as appropriate, will
        // have package name prepended
        ObjectInputStream ois = new ObjectInputStream( is );
        // R E A D
        GoList goList = ( GoList ) ois.readObject();
        // C L O S E
        ois.close();
        return goList;
        }

    /**
     * Add a triple to the GoList. All parameters are presumed to be trimmed.
     *
     * @param filename  Filename part of the URL. without lead mindprod/jgloss, with trailing .html Cross links will
     *                  have form ../bgloss/voip.html.  No trailing #XXXX.
     * @param target    target part of the URL, without the #
     * @param humanname Humanname for the link. No entities!
     */
    public void add( String filename, String target, String humanname )
        {
        filenames[ size ] = filename;
        targets[ size ] = target;
        humannames[ size ] = humanname;
        size++;
        }

    /**
     * Get the filename portion of the URL
     *
     * @param index Which element do you want?
     *
     * @return Filename as a trimmed string.
     */
    public String getFilename( int index )
        {
        return filenames[ index ];
        }

    /**
     * Get the human description of the link
     *
     * @param index Which element do you want?
     *
     * @return Human name as a trimmed string.
     */
    public String getHumanname( int index )
        {
        return humannames[ index ];
        }

    /**
     * Get the target part of the URL
     *
     * @param index Which element do you want?
     *
     * @return Target as a trimmed string.
     */
    public String getTarget( int index )
        {
        return targets[ index ];
        }

    /**
     * How many elements are currently in the GoList?
     *
     * @return size of of the GoList
     */
    public int size()
        {
        return size;
        }
    }