| package org.apache.turbine.services.cache; |
| |
| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2001-2003 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 apache@apache.org. |
| * |
| * 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/>. |
| */ |
| |
| /** |
| * The idea of the RefreshableCachedObject is that, rather than |
| * removing items from the cache when they become stale, we'll tell them to |
| * refresh themselves instead. That way they'll always be in the |
| * cache, and the code to refresh them will be run by the background |
| * thread rather than by a user request thread. You can also set a TTL (Time |
| * To Live) for the object. This way, if the object hasn't been touched |
| * for the TTL period, then it will be removed from the cache. |
| * |
| * This extends CachedObject and provides a method for refreshing the |
| * cached object, and resetting its expire time. |
| * |
| * @deprecated Use the Fulcrum Cache component instead. |
| * @author <a href="mailto:nissim@nksystems.com">Nissim Karpenstein</a> |
| * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> |
| * @version $Id$ |
| */ |
| public class RefreshableCachedObject |
| extends CachedObject |
| { |
| |
| /** |
| * How long to wait before removing an untouched object from the cache. |
| * Negative numbers mean never remove (the default). |
| */ |
| private long timeToLive = -1; |
| |
| /** |
| * The last time the Object was accessed from the cache. |
| */ |
| private long lastAccess; |
| |
| /** |
| * Constructor; sets the object to expire in the default time (30 |
| * minutes). |
| * |
| * @param o The object you want to cache. |
| */ |
| public RefreshableCachedObject(Refreshable o) |
| { |
| super(o); |
| lastAccess = System.currentTimeMillis(); |
| } |
| |
| /** |
| * Constructor. |
| * |
| * @param o The object to cache. |
| * @param expires How long before the object expires, in ms, |
| * e.g. 1000 = 1 second. |
| */ |
| public RefreshableCachedObject(Refreshable o, |
| long expires) |
| { |
| super(o, expires); |
| lastAccess = System.currentTimeMillis(); |
| } |
| |
| /** |
| * Sets the timeToLive value |
| * |
| * @param timeToLive the new Value in milliseconds |
| */ |
| public synchronized void setTTL(long timeToLive) |
| { |
| this.timeToLive = timeToLive; |
| } |
| |
| /** |
| * Gets the timeToLive value. |
| * |
| * @return The current timeToLive value (in milliseconds) |
| */ |
| public synchronized long getTTL() |
| { |
| return timeToLive; |
| } |
| |
| /** |
| * Sets the last acccess time to the current time. |
| */ |
| public synchronized void touch() |
| { |
| lastAccess = System.currentTimeMillis(); |
| } |
| |
| /** |
| * Returns true if the object hasn't been touched |
| * in the previous TTL period. |
| */ |
| public synchronized boolean isUntouched() |
| { |
| if (timeToLive < 0) |
| return false; |
| |
| if (lastAccess + timeToLive < System.currentTimeMillis()) |
| return true; |
| else |
| return false; |
| } |
| |
| /** |
| * Refresh the object and the created time. |
| */ |
| public void refresh() |
| { |
| Refreshable r = (Refreshable) getContents(); |
| synchronized (this) |
| { |
| created = System.currentTimeMillis(); |
| r.refresh(); |
| } |
| } |
| } |