javax.ws.rs.client.FactoryFinder Maven / Gradle / Ivy
Show all versions of ehcache Show documentation
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2010-2013 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* http://glassfish.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package javax.ws.rs.client;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Factory finder utility class.
*
* @author Paul Sandoz
* @author Marc Hadley
* @since 1.0
*/
final class FactoryFinder {
private static final Logger LOGGER = Logger.getLogger(FactoryFinder.class.getName());
private FactoryFinder() {
// prevents instantiation
}
static ClassLoader getContextClassLoader() {
return AccessController.doPrivileged(
new PrivilegedAction() {
@Override
public ClassLoader run() {
ClassLoader cl = null;
try {
cl = Thread.currentThread().getContextClassLoader();
} catch (SecurityException ex) {
LOGGER.log(
Level.WARNING,
"Unable to get context classloader instance.",
ex);
}
return cl;
}
});
}
/**
* Creates an instance of the specified class using the specified
* ClassLoader object.
*
* @param className name of the class to be instantiated.
* @param classLoader class loader to be used.
* @return instance of the specified class.
* @throws ClassNotFoundException if the given class could not be found
* or could not be instantiated
*/
private static Object newInstance(final String className, final ClassLoader classLoader) throws ClassNotFoundException {
try {
Class spiClass;
if (classLoader == null) {
spiClass = Class.forName(className);
} else {
try {
spiClass = Class.forName(className, false, classLoader);
} catch (ClassNotFoundException ex) {
LOGGER.log(
Level.FINE,
"Unable to load provider class " + className
+ " using custom classloader " + classLoader.getClass().getName()
+ " trying again with current classloader.",
ex);
spiClass = Class.forName(className);
}
}
return spiClass.newInstance();
} catch (ClassNotFoundException x) {
throw x;
} catch (Exception x) {
throw new ClassNotFoundException("Provider " + className + " could not be instantiated: " + x, x);
}
}
/**
* Finds the implementation Class object for the given
* factory name, or if that fails, finds the Class object
* for the given fallback class name. The arguments supplied MUST be
* used in order. If using the first argument is successful, the second
* one will not be used.
*
* This method is package private so that this code can be shared.
*
* @param factoryId the name of the factory to find, which is
* a system property
* @param fallbackClassName the implementation class name, which is
* to be used only if nothing else
* is found; null to indicate that
* there is no fallback class name
* @return the Class object of the specified message factory;
* may not be null
* @throws ClassNotFoundException if the given class could not be found
* or could not be instantiated
*/
static Object find(final String factoryId, final String fallbackClassName) throws ClassNotFoundException {
ClassLoader classLoader = getContextClassLoader();
String serviceId = "META-INF/services/" + factoryId;
// try to find services in CLASSPATH
try {
InputStream is;
if (classLoader == null) {
is = ClassLoader.getSystemResourceAsStream(serviceId);
} else {
is = classLoader.getResourceAsStream(serviceId);
}
if (is != null) {
BufferedReader rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
String factoryClassName = rd.readLine();
rd.close();
if (factoryClassName != null && !"".equals(factoryClassName)) {
return newInstance(factoryClassName, classLoader);
}
}
} catch (Exception ex) {
LOGGER.log(Level.FINER, "Failed to load service " + factoryId + " from " + serviceId, ex);
}
// try to read from $java.home/lib/jaxrs.properties
try {
String javah = System.getProperty("java.home");
String configFile = javah + File.separator
+ "lib" + File.separator + "jaxrs.properties";
File f = new File(configFile);
if (f.exists()) {
Properties props = new Properties();
props.load(new FileInputStream(f));
String factoryClassName = props.getProperty(factoryId);
return newInstance(factoryClassName, classLoader);
}
} catch (Exception ex) {
LOGGER.log(Level.FINER, "Failed to load service " + factoryId
+ " from $java.home/lib/jaxrs.properties", ex);
}
// Use the system property
try {
String systemProp = System.getProperty(factoryId);
if (systemProp != null) {
return newInstance(systemProp, classLoader);
}
} catch (SecurityException se) {
LOGGER.log(Level.FINER, "Failed to load service " + factoryId
+ " from a system property", se);
}
if (fallbackClassName == null) {
throw new ClassNotFoundException(
"Provider for " + factoryId + " cannot be found", null);
}
return newInstance(fallbackClassName, classLoader);
}
}