/*
* Copyright (c) 2002-2007 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* 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 Sun Microsystems, Inc. for JXTA(TM) technology."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
* not be used to endorse or promote products derived from this software
* without prior written permission. For written permission, please contact
* Project JXTA at http://www.jxta.org.
*
* 5. Products derived from this software may not be called "JXTA", nor may
* "JXTA" appear in their name, without prior written permission of Sun.
*
* 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 SUN
* MICROSYSTEMS 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.
*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* This software consists of voluntary contributions made by many individuals
* on behalf of Project JXTA. For more information on Project JXTA, please see
* http://www.jxta.org.
*
* This license is based on the BSD license adopted by the Apache Foundation.
*/
package net.jxta.impl.util;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.NoSuchElementException;
/**
* A dynamic {@link java.util.Enumeration} which allows items to added to the
* enumeration while it is in use. This is mostly intended for use with
* {@link java.io.SequenceInputStream}. When used with {@code SequenceInputStream}
* it is important to call {@code close()} on the enumeration before calling
* {@code close()} on the stream. Failing to do so will cause the stream to
* block as it tries to "drain" the enumeration.
*
* <p/>This class is entirely thread safe. Attempting to use the enumeration
* and to add objects from a single thread is not recommended, as it may
* deadlock the thread.
*
* @since 2.6 This class is not used anywhere and has been deprecated. It will be
* removed in the next release.
*
**/
@Deprecated
public class DynamicEnumeration implements Enumeration {
private List sequence = new ArrayList();
private volatile boolean closed = false;
/**
* Creates a new instance of DynamicEnumeration
**/
public DynamicEnumeration() {}
/**
* Creates a new instance of DynamicEnumeration
**/
public DynamicEnumeration(List initial) {
sequence.addAll(initial);
}
/**
* {@inheritDoc}
*
* <p/>If the Enumeration has not been closed we may have to block until we
* have a stream to return.
**/
public boolean hasMoreElements() {
while (!closed) {
synchronized (sequence) {
if (!sequence.isEmpty()) {
return true;
}
try {
sequence.wait();
} catch (InterruptedException woken) {
Thread.interrupted();
}
}
}
return false;
}
/**
* {@inheritDoc}
*
* <p/>If the Enumeration has not been closed we may have to block until we
* have a stream to return.
**/
public synchronized Object nextElement() {
while (!closed) {
synchronized (sequence) {
if (sequence.isEmpty()) {
try {
sequence.wait();
} catch (InterruptedException woken) {
Thread.interrupted();
}
continue;
}
Object result = sequence.remove(0);
return result;
}
}
throw new NoSuchElementException("No more elements");
}
/**
* Add another object to the enumeration.
**/
public void add(Object add) {
if (closed) {
throw new IllegalStateException("Enumeration was closed");
}
synchronized (sequence) {
sequence.add(add);
sequence.notify();
}
}
/**
* There will be no more objects added.
**/
public void close() {
closed = true;
synchronized (sequence) {
sequence.notify();
}
}
}