dlr 01/08/24 12:05:43
Added: util/src/java/org/apache/commons/util
EnumerationIterator.java
Log:
An Enumeration wrapper which implements the Iterator interface.
Revision Changes Path
1.1
jakarta-commons-sandbox/util/src/java/org/apache/commons/util/EnumerationIterator.java
Index: EnumerationIterator.java
===================================================================
package org.apache.commons.util;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache Turbine" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [EMAIL PROTECTED]
*
* 5. Products derived from this software may not be called "Apache",
* "Apache Turbine", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
/**
* An <code>Enumeration</code> wrapper class which implements the
* <code>Iterator</code> interface.
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Daniel Rall</a>
* @version $Id: EnumerationIterator.java,v 1.1 2001/08/24 19:05:43 dlr Exp $
*/
public class EnumerationIterator implements Iterator
{
private Collection collection;
private Enumeration enum;
private Object last = null;
/**
* Creates an instance on which {@link #remove()} can be called.
*
* @param enum The enumeration to wrap.
* @param collection The <code>Collection</code> being iterated.
*/
public EnumerationIterator(Enumeration enum, Collection collection)
{
if (enum != null)
{
this.enum = enum;
this.collection = collection;
}
else
{
throw new NullPointerException("enum cannot be null");
}
}
/**
* Creates an instance on which {@link #remove()} cannot be called.
*
* @param enum The enumeration to wrap.
*/
public EnumerationIterator(Enumeration enum)
{
this(enum, null);
}
public boolean hasNext()
{
return enum.hasMoreElements();
}
public Object next()
{
last = enum.nextElement();
return last;
}
/**
* Functions if an associated <code>Collection</code> is known.
*
* @exception IllegalStateException <code>next()</code> not called.
* @exception UnsupportedOperationException No associated
* <code>Collection</code>.
*/
public void remove()
{
if (collection != null)
{
if (last != null)
{
collection.remove(last);
}
else
{
throw new IllegalStateException
("next() must have been called for remove() to function");
}
}
else
{
throw new UnsupportedOperationException
("No Collection associated with this Iterator");
}
}
}
