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/**
* ================================================
* LibLoader : a free Java resource loading library
* ================================================
*
* Project Info: http://reporting.pentaho.org/libloader/
*
* (C) Copyright 2006, by Pentaho Corporation and Contributors.
*
* This library is free software; you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Foundation;
* either version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
*
* ------------
* $Id: CachingResourceData.java 3520 2007-10-16 10:34:47Z tmorgner $
* ------------
* (C) Copyright 2006, by Pentaho Corporation.
*/
package org.jfree.resourceloader.cache;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.Serializable;
import java.util.HashMap;
import org.jfree.resourceloader.ResourceData;
import org.jfree.resourceloader.ResourceKey;
import org.jfree.resourceloader.ResourceLoadingException;
import org.jfree.resourceloader.ResourceManager;
/**
* A very simple implementation which is suitable for smaller objects. The
* complete data is read into memory.
*
* @author Thomas Morgner
*/
public class CachingResourceData implements ResourceData, Serializable
{
private static final int CACHE_THRESHOLD = 512*1024;
private ResourceData data;
private HashMap attributes;
// The cached raw data. This is stored on the serialized stream as well
// so that we can cache that stuff.
private byte[] rawData;
public CachingResourceData(final ResourceData data)
{
if (data == null)
{
throw new NullPointerException();
}
this.data = data;
}
public InputStream getResourceAsStream(final ResourceManager caller) throws ResourceLoadingException
{
final byte[] data = getResource(caller);
return new ByteArrayInputStream(data);
}
public synchronized byte[] getResource(final ResourceManager caller) throws ResourceLoadingException
{
if (rawData == null)
{
rawData = data.getResource(caller);
}
return (byte[]) rawData.clone();
}
public synchronized int getResource
(final ResourceManager caller, final byte[] target, final int offset, final int length)
throws ResourceLoadingException
{
if (target == null)
{
throw new NullPointerException();
}
if (target.length < (offset + length))
{
throw new IndexOutOfBoundsException();
}
if (rawData == null)
{
rawData = data.getResource(caller);
}
final int maxLength = Math.min (rawData.length - offset, length);
if (maxLength <= 0)
{
return -1;
}
System.arraycopy(rawData, offset, target, 0, maxLength);
return maxLength;
}
public synchronized Object getAttribute(final String key)
{
if (attributes == null)
{
attributes = new HashMap();
}
else
{
final Object cached = attributes.get(key);
if (cached != null)
{
return cached;
}
}
final Object value = data.getAttribute(key);
if (value != null)
{
attributes.put(key, value);
}
return value;
}
public ResourceKey getKey()
{
return data.getKey();
}
public long getVersion(final ResourceManager caller)
throws ResourceLoadingException
{
return data.getVersion(caller);
}
public static ResourceData createCached(final ResourceData data)
{
// this relieves the pain of having to re-open the same stream more than
// once. This is no real long term caching, but at least a caching during
// the current request.
final Object rawCl = data.getAttribute(ResourceData.CONTENT_LENGTH);
if (rawCl instanceof Number)
{
final Number contentLength = (Number) rawCl;
if (contentLength.intValue() < CACHE_THRESHOLD)
{
// only buffer all data if the content is less than 512kb.
// Else, we may run into trouble if we try to load a huge item into memory ..
return new CachingResourceData(data);
}
}
return data;
}
}
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