- /*
- * $Header$
- * $Revision$
- * $Date$
- *
- * ====================================================================
- *
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 1999-2002 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 acknowlegement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowlegement may appear in the software itself,
- * if and wherever such third-party acknowlegements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- * Foundation" 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"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Group.
- *
- * 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/>.
- *
- */
-
- package org.apache.commons.discovery.tools;
-
- import org.apache.commons.discovery.ResourceClass;
- import org.apache.commons.discovery.ResourceClassIterator;
- import org.apache.commons.discovery.resource.classes.DiscoverClasses;
- import org.apache.commons.discovery.resource.ClassLoaders;
-
-
- /**
- * Holder for a default class.
- *
- * Class may be specified by name (String) or class (Class).
- * Using the holder complicates the users job, but minimized # of API's.
- *
- * @author Richard A. Sitze
- */
- public class DefaultClassHolder {
- private Class defaultClass;
- private final String defaultName;
-
- public DefaultClassHolder(Class defaultClass) {
- this.defaultClass = defaultClass;
- this.defaultName = defaultClass.getName();
- }
-
- public DefaultClassHolder(String defaultName) {
- this.defaultClass = null;
- this.defaultName = defaultName;
- }
-
- /**
- * @param spi non-null SPI
- * @param loaders Used only if class needs to be loaded.
- *
- * @return Default Class. Load the class if necessary,
- * and verify that it implements the SPI.
- * (this forces the check, no way out..).
- */
- public Class getDefaultClass(SPInterface spi, ClassLoaders loaders) {
- if (defaultClass == null) {
- DiscoverClasses classDiscovery = new DiscoverClasses(loaders);
- ResourceClassIterator classes = classDiscovery.findResourceClasses(getDefaultName());
- if (classes.hasNext()) {
- ResourceClass info = classes.nextResourceClass();
- try {
- defaultClass = info.loadClass();
- } catch (Exception e) {
- // ignore
- }
- }
- }
-
- if (defaultClass != null) {
- spi.verifyAncestory(defaultClass);
- }
-
- return defaultClass;
- }
-
- public String getDefaultName() {
- return defaultName;
- }
- }