/*
* ====================================================================
*
* Frame2 Open Source License
*
* Copyright (c) 2004-2007 Megatome Technologies. 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
* Megatome Technologies."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Frame2 Project", and "Frame2",
* must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact iamthechad@sourceforge.net.
*
* 5. Products derived from this software may not be called "Frame2"
* nor may "Frame2" appear in their names without prior written
* permission of Megatome Technologies.
*
* 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 MEGATOME TECHNOLOGIES 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.
* ====================================================================
*/
package org.megatome.frame2.log;
import java.lang.reflect.Constructor;
import org.megatome.frame2.log.impl.StandardLogger;
import org.megatome.frame2.log.impl.StdoutLogger;
/**
* The LoggerFactory generates instances of the Logger instances as used by the
* framework. The Logger implementation is normally set through the
* Frame2ContextListener.
*/
public class LoggerFactory {
private static Constructor<?> loggerConstructor;
private static boolean STD_LOGGING_AVAILABLE = true;
/**
* Constructor for LoggerFactory.
*/
private LoggerFactory() {
// not public
}
/**
* Creates a logger for the given name corresponding to the type set in
* setType, otherwise returns a StandardLogger (if available) or a cruddy
* StdoutLogger.
* @param name The log instance name to create
* @return Logger instance
*/
public static Logger instance(String name) {
if (loggerConstructor != null) {
try {
Object o = loggerConstructor.newInstance(new Object[] { name });
return (Logger)o;
} catch (Exception e) {
throw new RuntimeException("Instantiating object failed.", e); //$NON-NLS-1$
}
}
return getDefault(name);
}
static private Logger getDefault(String name) {
Logger result = null;
if (STD_LOGGING_AVAILABLE) {
try {
result = new StandardLogger(name);
} catch (Throwable t) {
STD_LOGGING_AVAILABLE = false;
}
}
if (result == null) {
result = new StdoutLogger(name);
}
return result;
}
/**
* Sets the Logger implementation for use by the framework. The factory will
* use the provided class loader to generate the instances.
* @param className The fully qualified name of the Logger implementation.
* The class must implement the Logger interface and provide a public
* constructor that takes a string argument, which is its name.
* @param classLoader The class loader to use.
*/
public static void setType(String className, ClassLoader classLoader)
throws LoggerException {
Class<?> loggerClass = null;
try {
loggerClass = classLoader.loadClass(className);
Class<?>[] interfaces = loggerClass.getInterfaces();
boolean loggerIntFound = false;
for (int i = 0; i < interfaces.length; i++) {
if (interfaces[i] == Logger.class) {
loggerIntFound = true;
break;
}
}
if (!loggerIntFound) {
loggerConstructor = null;
throw new LoggerException(className + " does not implement " //$NON-NLS-1$
+ Logger.class.getName());
}
} catch (ClassNotFoundException e) {
loggerConstructor = null;
throw new LoggerException("Unable to load class " + className, e); //$NON-NLS-1$
}
try {
loggerConstructor = loggerClass
.getConstructor(new Class[] { String.class });
} catch (NoSuchMethodException e) {
loggerConstructor = null;
throw new LoggerException("Invalid constructor for " + loggerClass, //$NON-NLS-1$
e);
}
}
}