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/*
* Copyright 2002-2023 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
*
* https://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.apache.commons.logging;
/**
* A minimal incarnation of Apache Commons Logging's {@code LogFactory} API,
* providing just the common {@link Log} lookup methods. This is inspired
* by the JCL-over-SLF4J bridge and should be source as well as binary
* compatible with all common use of the Commons Logging API (in particular:
* with {@code LogFactory.getLog(Class/String)} field initializers).
*
* This implementation does not support Commons Logging's original provider
* detection. It rather only checks for the presence of the Log4j 2.x API
* and the SLF4J 1.7 API in the Spring Framework classpath, falling back to
* {@code java.util.logging} if none of the two is available. In that sense,
* it works as a replacement for the Log4j 2 Commons Logging bridge as well as
* the JCL-over-SLF4J bridge, both of which become irrelevant for Spring-based
* setups as a consequence (with no need for manual excludes of the standard
* Commons Logging API jar anymore either). Furthermore, for simple setups
* without an external logging provider, Spring does not require any extra jar
* on the classpath anymore since this embedded log factory automatically
* delegates to {@code java.util.logging} in such a scenario.
*
*
Note that this Commons Logging variant is only meant to be used for
* infrastructure logging purposes in the core framework and in extensions.
* It also serves as a common bridge for third-party libraries using the
* Commons Logging API, for example, Apache HttpClient, and HtmlUnit, bringing
* them into the same consistent arrangement without any extra bridge jars.
*
*
For logging need in application code, prefer direct use of Log4j 2.x
* or SLF4J or {@code java.util.logging}. Simply put Log4j 2.x or Logback
* (or another SLF4J provider) onto your classpath, without any extra bridges,
* and let the framework auto-adapt to your choice.
*
* @author Juergen Hoeller (for the {@code spring-jcl} variant)
* @since 5.0
*/
public abstract class LogFactory {
/**
* Convenience method to return a named logger.
* @param clazz containing Class from which a log name will be derived
*/
public static Log getLog(Class clazz) {
return getLog(clazz.getName());
}
/**
* Convenience method to return a named logger.
* @param name logical name of the Log instance to be returned
*/
public static Log getLog(String name) {
return LogAdapter.createLog(name);
}
/**
* This method only exists for compatibility with unusual Commons Logging API
* usage like, for example, {@code LogFactory.getFactory().getInstance(Class/String)}.
* @see #getInstance(Class)
* @see #getInstance(String)
* @deprecated in favor of {@link #getLog(Class)}/{@link #getLog(String)}
*/
@Deprecated
public static LogFactory getFactory() {
return new LogFactory() {
@Override
public Object getAttribute(String name) {
return null;
}
@Override
public String[] getAttributeNames() {
return new String[0];
}
@Override
public void removeAttribute(String name) {
}
@Override
public void setAttribute(String name, Object value) {
}
@Override
public void release() {
}
};
}
/**
* Convenience method to return a named logger.
*
This variant just dispatches straight to {@link #getLog(Class)}.
* @param clazz containing Class from which a log name will be derived
* @deprecated in favor of {@link #getLog(Class)}
*/
@Deprecated
public Log getInstance(Class clazz) {
return getLog(clazz);
}
/**
* Convenience method to return a named logger.
*
This variant just dispatches straight to {@link #getLog(String)}.
* @param name logical name of the Log instance to be returned
* @deprecated in favor of {@link #getLog(String)}
*/
@Deprecated
public Log getInstance(String name) {
return getLog(name);
}
// Just in case some code happens to call uncommon Commons Logging methods...
@Deprecated
public abstract Object getAttribute(String name);
@Deprecated
public abstract String[] getAttributeNames();
@Deprecated
public abstract void removeAttribute(String name);
@Deprecated
public abstract void setAttribute(String name, Object value);
@Deprecated
public abstract void release();
@Deprecated
public static void release(ClassLoader classLoader) {
// do nothing
}
@Deprecated
public static void releaseAll() {
// do nothing
}
@Deprecated
public static String objectId(Object o) {
return (o == null ? "null" : o.getClass().getName() + "@" + System.identityHashCode(o));
}
}