/**
* ================================================
* 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: AbstractResourceFactory.java,v 1.5 2007/04/01 13:43:17 taqua Exp $
* ------------
* (C) Copyright 2006, by Pentaho Corporation.
*/
package org.jfree.resourceloader.factory;
import java.util.HashSet;
import java.util.Iterator;
import java.util.TreeSet;
import org.jfree.resourceloader.LibLoaderBoot;
import org.jfree.resourceloader.Resource;
import org.jfree.resourceloader.ResourceCreationException;
import org.jfree.resourceloader.ResourceData;
import org.jfree.resourceloader.ResourceFactory;
import org.jfree.resourceloader.ResourceLoadingException;
import org.jfree.resourceloader.ResourceKey;
import org.jfree.resourceloader.ResourceManager;
import org.jfree.resourceloader.ContentNotRecognizedException;
import org.jfree.util.Configuration;
import org.jfree.util.ObjectUtilities;
import org.jfree.util.Log;
/**
* Creation-Date: 05.04.2006, 16:58:57
*
* @author Thomas Morgner
*/
public abstract class AbstractResourceFactory implements ResourceFactory
{
private static class ResourceFactoryEntry implements Comparable
{
private FactoryModule module;
private int weight;
public ResourceFactoryEntry(final FactoryModule module, final int weight)
{
this.module = module;
this.weight = weight;
}
public FactoryModule getModule()
{
return module;
}
public int getWeight()
{
return weight;
}
/**
* Compares this object with the specified object for order. Returns a
* negative integer, zero, or a positive integer as this object is less than,
* equal to, or greater than the specified object.<p>
*
* "Note: this class has a natural ordering that is inconsistent with
* equals."
*
* @param o the Object to be compared.
* @return a negative integer, zero, or a positive integer as this object is
* less than, equal to, or greater than the specified object.
* @throws ClassCastException if the specified object's type prevents it from
* being compared to this Object.
*/
public int compareTo(final Object o)
{
final ResourceFactoryEntry entry = (ResourceFactoryEntry) o;
// the order is intentionally reveresed, so that a sorted set has the best
// fit as first entry.
return entry.weight - weight;
}
}
/** The available factory methods. */
private HashSet factoryModules;
/** Which type of objects do we create here? */
private Class factoryType;
protected AbstractResourceFactory(final Class factoryType)
{
if (factoryType == null)
{
throw new NullPointerException();
}
this.factoryType = factoryType;
this.factoryModules = new HashSet();
}
public Class getFactoryType()
{
return factoryType;
}
public void initializeDefaults ()
{
final String type = getFactoryType().getName();
final String prefix = CONFIG_PREFIX + type;
final Configuration config = LibLoaderBoot.getInstance().getGlobalConfig();
final Iterator itType = config.findPropertyKeys(prefix);
while (itType.hasNext())
{
final String key = (String) itType.next();
final String modClass = config.getConfigProperty(key);
final Object maybeFactory = ObjectUtilities.loadAndInstantiate
(modClass, AbstractResourceFactory.class, FactoryModule.class);
if (maybeFactory instanceof FactoryModule == false)
{
continue;
}
registerModule((FactoryModule) maybeFactory);
}
}
public synchronized boolean registerModule(final String className)
{
try
{
final Class c = ObjectUtilities.getClassLoader
(getClass()).loadClass(className);
registerModule((FactoryModule) c.newInstance());
return true;
}
catch (Exception e)
{
return false;
}
}
public synchronized void registerModule(final FactoryModule module)
{
if (factoryModules.contains(module))
{
return;
}
factoryModules.add(module);
}
/**
*
* @param data
* @param context
* @return
* @throws ResourceCreationException
* @throws ResourceLoadingException
*/
public synchronized Resource create(final ResourceManager manager,
final ResourceData data,
final ResourceKey context)
throws ResourceCreationException, ResourceLoadingException
{
final TreeSet sortedEntries = new TreeSet();
final Iterator factoryModulesIt = factoryModules.iterator();
while (factoryModulesIt.hasNext())
{
final FactoryModule mod = (FactoryModule) factoryModulesIt.next();
int weight = mod.canHandleResource(manager, data);
if (weight >= 0)
{
sortedEntries.add(new ResourceFactoryEntry(mod, weight));
}
}
final Iterator it = sortedEntries.iterator();
while (it.hasNext())
{
final ResourceFactoryEntry entry = (ResourceFactoryEntry) it.next();
try
{
return entry.getModule().create(manager, data, context);
}
catch(Exception ex)
{
// ok, that one failed, try the next one ...
}
}
throw new ContentNotRecognizedException
("No valid handler for the given content.");
}
}