PaginatedList.java

package me.smorce.thanalogic;

import java.util.List;
import net.md_5.bungee.api.ChatColor;
import net.md_5.bungee.api.chat.BaseComponent;
import net.md_5.bungee.api.chat.ClickEvent;
import net.md_5.bungee.api.chat.ComponentBuilder;
import net.md_5.bungee.api.chat.HoverEvent;
import net.md_5.bungee.api.chat.TextComponent;

public class PaginatedList
{
    private final String header;
    private final int pageSize;
    private final List<BaseComponent> contents;
    private final String pageChangeCommand;
    private final int pages;

    /**
     * Stores TextComponent objects that can be fetched in paginated form
     *
     * @param header
     *            - the header displayed at the top of each page
     * @param pageSize
     *            - the number of contents per page, a page size of 0 indicates that there will only be one page
     * @param contents
     *            - the list of contents to be paginated
     * @param pageChangeCommand
     *            - the command to use when changing pages
     */
    public PaginatedList(String header, Integer pageSize, List<BaseComponent> contents, String pageChangeCommand)
    {
        this.header = header;
        if(pageSize == null)
        {
            pageSize = contents.size();
        }
        this.pageSize = pageSize;
        this.contents = contents;
        this.pageChangeCommand = pageChangeCommand;
        pages = contents.size() / pageSize;
    }

    public BaseComponent getPage(int page)
    {
        page = Math.min(pages, Math.max(1, page));
        ComponentBuilder builder = new ComponentBuilder(this.header + " - ");
        builder.color(ChatColor.BLUE).bold(true);
        if(page != 1)
        {
            builder.append("[Previous] ").bold(false)
                    .event(new HoverEvent(HoverEvent.Action.SHOW_TEXT,
                            new ComponentBuilder("Click here to go to the previous page").create()))
                    .event(new ClickEvent(ClickEvent.Action.RUN_COMMAND, this.pageChangeCommand + (page - 1)));
        }
        builder.append("Page " + page + "/" + pages).bold(false);
        if(page != pages)
        {
            builder.append(" - [Next]")
                    .event(new HoverEvent(HoverEvent.Action.SHOW_TEXT,
                            new ComponentBuilder("Click here to go to the next page").create()))
                    .event(new ClickEvent(ClickEvent.Action.RUN_COMMAND, this.pageChangeCommand + (page + 1)));
        }
        TextComponent content = new TextComponent(builder.create() + "\n");
        int firstIndex = pageSize * (page - 1);
        int lastIndex = Math.min(firstIndex + pageSize, this.contents.size() - 1);
        for(int i = firstIndex; i < lastIndex; i++)
        {
            content.addExtra(new TextComponent(this.contents.get(i) + "\n"));
        }
        return content;
    }

    public BaseComponent getPage()
    {
        return getPage(1);
    }

    public String getHeader()
    {
        return header;
    }

    public int getPageSize()
    {
        return pageSize;
    }

    public List<BaseComponent> getContents()
    {
        return contents;
    }
}