/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.wicket.markup.html.list;
import java.util.Iterator;
import org.apache.wicket.Component;
import org.apache.wicket.markup.repeater.AbstractRepeater;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.util.collections.ReadOnlyIterator;
/**
* A very simple loop component whose model is an Integer defining the number of iterations the loop
* should render. During rendering, Loop iterates from 0 to getIterations() - 1, creating a new
* MarkupContainer for each iteration. The MarkupContainer is populated by the Loop subclass by
* implementing the abstract method populate(LoopItem). The populate() method is called just before
* the LoopItem container is rendered.
*
* @author Juergen Donnerstag
* @author Eelco Hillenius
* @author Jonathan Locke
*/
public abstract class Loop extends AbstractRepeater
{
private static final long serialVersionUID = 1L;
/**
* Construct.
*
* @param id
* See Component
* @param iterations
* max index of the loop
* @see org.apache.wicket.Component#Component(String, IModel)
*/
public Loop(final String id, final int iterations)
{
super(id, new Model<Integer>(iterations));
}
/**
* Construct.
*
* @param id
* See Component
* @param model
* Must contain a Integer model object
* @see org.apache.wicket.Component#Component(String, IModel)
*/
public Loop(final String id, final IModel<Integer> model)
{
super(id, model);
}
/**
* @return The number of loop iterations
*/
public final int getIterations()
{
return (Integer)getDefaultModelObject();
}
/**
* @see org.apache.wicket.Component#onBeforeRender()
*/
@Override
protected final void onPopulate()
{
// Remove any previous loop contents
removeAll();
// Get number of iterations
final int iterations = getIterations();
if (iterations > 0)
{
// Create LoopItems for each iteration
for (int iteration = 0; iteration < iterations; iteration++)
{
// Create item for loop iteration
LoopItem item = newItem(iteration);
// Add and populate item
add(item);
populateItem(item);
}
}
}
/**
* Create a new LoopItem for loop at iteration.
*
* @param iteration
* iteration in the loop
* @return LoopItem
*/
protected LoopItem newItem(int iteration)
{
return new LoopItem(iteration);
}
/**
* @see org.apache.wicket.markup.repeater.AbstractRepeater#renderIterator()
*/
@Override
protected Iterator<Component> renderIterator()
{
final int iterations = size();
return new ReadOnlyIterator<Component>()
{
private int index = 0;
@Override
public boolean hasNext()
{
return index < iterations;
}
@Override
public Component next()
{
return get(Integer.toString(index++));
}
};
}
/**
* Populates this loop item.
*
* @param item
* The iteration of the loop
*/
protected abstract void populateItem(LoopItem item);
/**
* @param child
*/
@Override
protected final void renderChild(Component child)
{
renderItem((LoopItem)child);
}
/**
* Renders this loop iteration.
*
* @param item
* The loop iteration
*/
protected void renderItem(final LoopItem item)
{
item.render();
}
}