package com.wutka.dtd;import java.io.*;import java.util.*;/** Represents an item that may contain other items (such as a * DTDChoice or a DTDSequence) * * @author Mark Wutka * @version $Revision: 1.16 $ $Date: 2002/07/19 01:20:11 $ by $Author: wutka $ */public abstract class DTDContainer extends DTDItem{    protected Vector items;/** Creates a new DTDContainer */    public DTDContainer()    {        items = new Vector();    }/** Adds an element to the container */    public void add(DTDItem item)    {        items.addElement(item);    }/** Removes an element from the container */    public void remove(DTDItem item)    {        items.removeElement(item);    }/** Returns the elements as a vector (not a clone!) */    public Vector getItemsVec()    {        return items;    }/** Returns the elements as an array of items */    public DTDItem[] getItems()    {        DTDItem[] retval = new DTDItem[items.size()];        items.copyInto(retval);        return retval;    }    public boolean equals(Object ob)    {       if (ob == this) return true;        if (!(ob instanceof DTDContainer)) return false;        if (!super.equals(ob)) return false;        DTDContainer other = (DTDContainer) ob;        return items.equals(other.items);    }/** Stores items in the container */    public void setItem(DTDItem[] newItems)    {        items = new Vector(newItems.length);        for (int i=0; i < newItems.length; i++)        {            items.addElement(newItems[i]);        }    }/** Retrieves the items in the container */    public DTDItem[] getItem()    {        DTDItem[] retval  = new DTDItem[items.size()];        items.copyInto(retval);        return retval;    }/** Stores an item in the container */    public void setItem(DTDItem anItem, int i)    {        items.setElementAt(anItem, i);    }/** Retrieves an item from the container */    public DTDItem getItem(int i)    {        return (DTDItem) items.elementAt(i);    }    public abstract void write(PrintWriter out)        throws IOException;}