_ComponentChildrenList.java

/*
 * Copyright 2004 The Apache Software Foundation.
 *
 * Licensed 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 javax.faces.component;

import java.io.Serializable;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.List;

/**
 * @author Manfred Geiler (latest modification by $Author$)
 * @version $Revision$ $Date$
 */
class _ComponentChildrenList
        extends AbstractList
        implements Serializable
{
	private static final long serialVersionUID = -6775078929331154224L;
	private UIComponent _component;
    private List _list = new ArrayList();

    _ComponentChildrenList(UIComponent component)
    {
        _component = component;
    }

    public Object get(int index)
    {
        return _list.get(index);
    }

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

    public Object set(int index, Object value)
    {
        checkValue(value);
        setNewParent((UIComponent)value);
        UIComponent child = (UIComponent) _list.set(index, value);
        if (child != null) child.setParent(null);
        return child;
    }

    public boolean add(Object value)
    {
        checkValue(value);
        setNewParent((UIComponent)value);
        return _list.add(value);
    }

    public void add(int index, Object value)
    {
        checkValue(value);
        setNewParent((UIComponent)value);
        _list.add(index, value);
    }

    public Object remove(int index)
    {
        UIComponent child = (UIComponent) _list.remove(index);
        if (child != null) child.setParent(null);
        return child;
    }


    private void setNewParent(UIComponent child)
    {
        UIComponent oldParent = child.getParent();
        if (oldParent != null)
        {
            oldParent.getChildren().remove(child);
        }
        child.setParent(_component);
    }

    private void checkValue(Object value)
    {
        if (value == null) throw new NullPointerException("value");
        if (!(value instanceof UIComponent)) throw new ClassCastException("value is not a UIComponent");
    }

}