-/*
- * Copyright 2005-2010 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.wamblee.general;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
-import org.wamblee.io.ClassPathResource;
-import org.wamblee.io.InputResource;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-import java.util.Properties;
-
-/**
- * The standard means to obtain the bean factory. This works by reading a
- * property {@value #BEAN_FACTORY_CLASS} from a property file named
- * {@value #BEAN_KERNEL_PROP_FILE} from the class path. This property identifies
- * the bean factory implementation to use. The configured bean factory must have
- * a no-arg constructor.
- */
-public final class BeanKernel {
- private static final Log LOG = LogFactory.getLog(BeanKernel.class);
-
- /**
- * Bean factory kernel properties file.
- */
- private static final String BEAN_KERNEL_PROP_FILE = "org.wamblee.beanfactory.properties";
-
- /**
- * Name of the property to define the name of the bean factory class to use.
- * THis class must have a public default constructor.
- */
- private static final String BEAN_FACTORY_CLASS = "org.wamblee.beanfactory.class";
-
- /**
- * Cached bean factory.
- */
- private static BeanFactory BEAN_FACTORY;
-
- /**
- * Disabled constructor.
- *
- */
- private BeanKernel() {
- // Empty
- }
-
- /**
- * Overrides the default mechanism for looking up the bean factory by
- * specifying it yourself.
- *
- * @param aOverride
- * Override bean factory.
- */
- public static void overrideBeanFactory(BeanFactory aOverride) {
- BEAN_FACTORY = aOverride;
- }
-
- /**
- * Gets the bean factory.
- *
- * @return Bean factory.
- */
- public static BeanFactory getBeanFactory() {
- synchronized (BeanFactory.class) {
- if (BEAN_FACTORY == null) {
- BEAN_FACTORY = lookupBeanFactory(BEAN_KERNEL_PROP_FILE);
- }
- }
-
- return BEAN_FACTORY;
- }
-
- /**
- * Lookup the bean factory based on the properties file.
- *
- *
- * @return Bean factory.
- *
- */
- static BeanFactory lookupBeanFactory(String aPropertyFilename) {
- InputResource resource = new ClassPathResource(aPropertyFilename);
- InputStream is;
-
- try {
- is = resource.getInputStream();
- } catch (IOException e) {
- throw new BeanFactoryException("Cannot open resource " + resource,
- e);
- }
-
- try {
- Properties props = new Properties();
- props.load(is);
-
- String className = props.getProperty(BEAN_FACTORY_CLASS);
- Class beanFactory = Class.forName(className);
-
- return (BeanFactory) beanFactory.newInstance();
- } catch (Exception e) {
- throw new BeanFactoryException("Cannot read from resource " +
- resource, e);
- } finally {
- try {
- is.close();
- } catch (IOException e) {
- // last resort cannot do much now.
- LOG.error("Error closing resource " + resource);
- }
- }
- }
-}