TypeMapper.java

/*
 * Copyright (c) 2007-2009, James Leigh All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * - 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. 
 * - Neither the name of the openrdf.org nor the names of its contributors may
 *   be used to endorse or promote products derived from this software without
 *   specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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.
 * 
 */
package org.openrdf.repository.object.managers.helpers;

import java.net.URL;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.openrdf.model.URI;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Maps concepts to their primary subject type.
 * 
 * @author James Leigh
 * 
 */
public class TypeMapper implements Cloneable {

	private final Logger logger = LoggerFactory.getLogger(TypeMapper.class);

	private Map<Class<?>, URI> types;

	public TypeMapper() {
		types = new ConcurrentHashMap<Class<?>, URI>(256);
	}

	public TypeMapper clone() {
		try {
			TypeMapper cloned = (TypeMapper) super.clone();
			cloned.types = new ConcurrentHashMap<Class<?>, URI>(types);
			return cloned;
		} catch (CloneNotSupportedException e) {
			throw new AssertionError(e);
		}
	}

	/**
	 * Finds the rdfs:Class for this Java Class<?>.
	 * 
	 * @param role
	 * @return URI of the rdf:Class<?> for this Java Class<?> or null.
	 */
	public URI findType(Class<?> role) {
		return types.get(role);
	}

	public synchronized void recordRole(Class<?> role, URI rdfType) {
		assert rdfType != null;
		if (!types.containsKey(role)) {
			types.put(role, rdfType);
			if (logger.isDebugEnabled()) {
				String sn = role.getSimpleName();
				String cn = role.getName().replace('.', '/') + ".class";
				ClassLoader cl = getClassLoader(role);
				URL location = cl.getResource(cn);
				logger.debug("Role {} loaded from {}", sn, location);
			}
		}
	}

	private ClassLoader getClassLoader(Class<?> role) {
		ClassLoader cl = role.getClassLoader();
		if (cl == null)
			cl = Thread.currentThread().getContextClassLoader();
		if (cl == null)
			cl = TypeMapper.class.getClassLoader();
		return cl;
	}
}