org.jboss.logging.generator.Tools Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source Copyright 2011, Red Hat, Inc., and
* individual contributors by the @authors tag. See the copyright.txt in the
* distribution for a full listing of individual contributors.
*
* This 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 software 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 software; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA, or see the FSF
* site: http://www.fsf.org.
*/
package org.jboss.logging.generator;
import org.jboss.logging.generator.apt.AptHelper;
import java.util.Arrays;
import java.util.ServiceLoader;
/**
* This class is not thread safe. The static methods use lazy loading for static
* variables.
*
* @author James R. Perkins - 21.Feb.2011
*/
public class Tools {
private static volatile AptHelper aptHelper;
private static volatile Annotations annotations;
private static volatile Loggers loggers;
private static final ServiceLoader aptHelperLoader = ServiceLoader.load(AptHelper.class, Tools.class.getClassLoader());
private static final ServiceLoader annotationsLoader = ServiceLoader.load(Annotations.class, Tools.class.getClassLoader());
private static final ServiceLoader loggersLoader = ServiceLoader.load(Loggers.class, Tools.class.getClassLoader());
private Tools() {
}
/**
* Locates the first implementation of {@link Annotations}.
*
* @return the annotations to use.
*
* @throws IllegalStateException if the implementation could not be found.
*/
public static Annotations annotations() {
if (annotationsLoader == null) {
throw servicesNotFound(Annotations.class);
}
Annotations result = annotations;
if (result == null) {
synchronized (annotationsLoader) {
result = annotations;
if (result == null) {
if (annotationsLoader.iterator().hasNext()) {
annotations = result = annotationsLoader.iterator().next();
} else {
throw servicesNotFound(Annotations.class);
}
}
}
}
return result;
}
/**
* Locates the first implementation of {@link Loggers}.
*
* @return the loggers to use.
*
* @throws IllegalStateException if the implementation could not be found.
*/
public static AptHelper aptHelper() {
if (aptHelperLoader == null) {
throw servicesNotFound(AptHelper.class);
}
AptHelper result = aptHelper;
if (result == null) {
synchronized (aptHelperLoader) {
result = aptHelper;
if (result == null) {
if (aptHelperLoader.iterator().hasNext()) {
aptHelper = result = aptHelperLoader.iterator().next();
} else {
throw servicesNotFound(AptHelper.class);
}
}
}
}
return result;
}
/**
* Locates the first implementation of {@link Loggers}.
*
* @return the loggers to use.
*
* @throws IllegalStateException if the implementation could not be found.
*/
public static Loggers loggers() {
if (loggersLoader == null) {
throw servicesNotFound(Loggers.class);
}
Loggers result = loggers;
if (result == null) {
synchronized (loggersLoader) {
result = loggers;
if (result == null) {
if (loggersLoader.iterator().hasNext()) {
loggers = result = loggersLoader.iterator().next();
} else {
throw servicesNotFound(Loggers.class);
}
}
}
}
return result;
}
private static IllegalStateException servicesNotFound(final Class clazz) {
final IllegalStateException result = new IllegalStateException(String.format("%1$s was not defined in META-INF/services/%1$s", clazz.getName()));
final StackTraceElement[] st = result.getStackTrace();
result.setStackTrace(Arrays.copyOfRange(st, 1, st.length));
return result;
}
}