A Simple Sortable DataTable Example

by Adam Koch

DataTablePage.java
package com.adamkoch.learning.wicket;

import org.apache.wicket.extensions.markup.html.repeater.data.table.DefaultDataTable;
import org.apache.wicket.extensions.markup.html.repeater.data.table.IColumn;
import org.apache.wicket.extensions.markup.html.repeater.data.table.PropertyColumn;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.model.Model;
import org.apache.wicket.model.StringResourceModel;

public class DataTablePage extends WebPage {
    
    public DataTablePage() {
        final UserProvider userProvider = new UserProvider();
        
        IColumn[] columns = new IColumn[2];
        columns[0] = new PropertyColumn(new StringResourceModel("firstNameTableHeaderLabel", this, null), "name.first", "name.first");
        columns[1] = new PropertyColumn(new Model("Last Name"), "name.last", "name.last");
        
        DefaultDataTable table = new DefaultDataTable("datatable", columns, userProvider, 10);
        
        add(table);
    }

}
UserProvider.java
package com.adamkoch.learning.wicket;

import java.io.Serializable;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

import org.apache.wicket.extensions.markup.html.repeater.util.SortableDataProvider;
import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.PropertyModel;

public class UserProvider extends SortableDataProvider {

	class SortableDataProviderComparator implements Comparator<Contact>, Serializable {
		public int compare(final Contact o1, final Contact o2) {
			PropertyModel<Comparable> model1 = new PropertyModel<Comparable>(o1, getSort().getProperty());
			PropertyModel<Comparable> model2 = new PropertyModel<Comparable>(o2, getSort().getProperty());

			int result = model1.getObject().compareTo(model2.getObject());

			if (!getSort().isAscending()) {
				result = -result;
			}

			return result;
		}

	}

	private List<Contact> list = new ArrayList<Contact>();
	private SortableDataProviderComparator comparator = new SortableDataProviderComparator();

	public UserProvider() {
		// The default sorting
		setSort("name.first", true);

		list.add(new Contact(new Name("Abby", "Zerind")));
		list.add(new Contact(new Name("Bernard", "Youst")));
		list.add(new Contact(new Name("Charlie", "Xerg")));
		list.add(new Contact(new Name("Deitri", "West")));
		list.add(new Contact(new Name("Ernie", "Vuntang")));
		list.add(new Contact(new Name("Frank", "Unter")));
	}

	public Iterator<Contact> iterator(final int first, final int count) {
		// In this example the whole list gets copied, sorted and sliced; in real applications typically your database would deliver a sorted and limited list 

		// Get the data
		List<Contact> newList = new ArrayList<Contact>(list);

		// Sort the data
		Collections.sort(newList, comparator);

		// Return the data for the current page - this can be determined only after sorting
		return newList.subList(first, first + count).iterator();
	}

	public IModel<Contact> model(final Object object) {
		return new AbstractReadOnlyModel<Contact>() {
			@Override
			public Contact getObject() {
				return (Contact) object;
			}
		};
	}

	public int size() {
		return list.size();
	}

}

class Contact implements Serializable {

	private final Name name;

	public Contact(final Name name) {
		this.name = name;
	}

	public Name getName() {
		return name;
	}
}

class Name implements Serializable {

	private String firstName;
	private String lastName;

	public Name(final String fName, final String lName) {
		firstName = fName;
		lastName = lName;
	}

	public String getFirst() {
		return firstName;
	}

	public String getLast() {
		return lastName;
	}

	public void setFirst(final String firstName) {
		this.firstName = firstName;
	}

	public void setLast(final String lastName) {
		this.lastName = lastName;
	}
}
DataTablePage.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
	<title>DataTable Example</title>
</head>

<body>
<table wicket:id="datatable"></table>
</body>
</html>
DataTablePage.properties
firstNameTableHeaderLabel=First Name

I'm not a Wicket developer or expert. Use at your own risk. If you find problems with this example, please edit this page.