org.apache.logging.log4j.util.StackLocatorUtil Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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.apache.logging.log4j.util;
import java.util.Deque;
import java.util.NoSuchElementException;
import java.util.function.Predicate;
import org.apache.logging.log4j.status.StatusLogger;
/**
* Consider this class private. Provides various methods to determine the caller class.
*/
@InternalApi
public final class StackLocatorUtil {
private static StackLocator stackLocator = null;
private static volatile boolean errorLogged;
static {
stackLocator = StackLocator.getInstance();
}
private StackLocatorUtil() {}
// TODO: return Object.class instead of null (though it will have a null ClassLoader)
// (MS) I believe this would work without any modifications elsewhere, but I could be wrong
// migrated from ReflectiveCallerClassUtility
@PerformanceSensitive
public static Class getCallerClass(final int depth) {
return stackLocator.getCallerClass(depth + 1);
}
public static StackTraceElement getStackTraceElement(final int depth) {
return stackLocator.getStackTraceElement(depth + 1);
}
/**
* Equivalent to {@link #getCallerClass(String, String)} with an empty {@code pkg}.
*/
// migrated from ClassLoaderContextSelector
@PerformanceSensitive
public static Class getCallerClass(final String fqcn) {
return getCallerClass(fqcn, Strings.EMPTY);
}
/**
* Search for a calling class.
*
* @param fqcn Root class name whose caller to search for.
* @param pkg Package name prefix that must be matched after the {@code fqcn} has been found.
* @return The caller class that was matched, or null if one could not be located.
*/
@PerformanceSensitive
public static Class getCallerClass(final String fqcn, final String pkg) {
return stackLocator.getCallerClass(fqcn, pkg);
}
/**
* Gets the ClassLoader of the class that called this method at the location up the call stack by the given
* stack frame depth.
*
* This method returns {@code null} if:
*
*
* - {@code sun.reflect.Reflection.getCallerClass(int)} is not present.
* - An exception is caught calling {@code sun.reflect.Reflection.getCallerClass(int)}.
* - Some Class implementations may use null to represent the bootstrap class loader.
*
*
* @param depth The stack frame count to walk.
* @return A class or null.
* @throws IndexOutOfBoundsException if depth is negative.
*/
@PerformanceSensitive
public static ClassLoader getCallerClassLoader(final int depth) {
final Class callerClass = stackLocator.getCallerClass(depth + 1);
return callerClass != null ? callerClass.getClassLoader() : null;
}
/**
* Search for a calling class.
*
* @param sentinelClass Sentinel class at which to begin searching
* @param callerPredicate Predicate checked after the sentinelClass is found
* @return the first matching class after sentinelClass is found.
*/
@PerformanceSensitive
public static Class getCallerClass(final Class sentinelClass, final Predicate> callerPredicate) {
return stackLocator.getCallerClass(sentinelClass, callerPredicate);
}
// added for use in LoggerAdapter implementations mainly
@PerformanceSensitive
public static Class getCallerClass(final Class anchor) {
return stackLocator.getCallerClass(anchor);
}
// migrated from ThrowableProxy
@PerformanceSensitive
public static Deque> getCurrentStackTrace() {
return stackLocator.getCurrentStackTrace();
}
public static StackTraceElement calcLocation(final String fqcnOfLogger) {
try {
return stackLocator.calcLocation(fqcnOfLogger);
} catch (NoSuchElementException ex) {
if (!errorLogged) {
errorLogged = true;
StatusLogger.getLogger().warn("Unable to locate stack trace element for {}", fqcnOfLogger, ex);
}
return null;
}
}
}