com.google.common.flogger.backend.system.StackBasedCallerFinder Maven / Gradle / Ivy
/*
* Copyright (C) 2018 The Flogger 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
*
* 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 com.google.common.flogger.backend.system;
import com.google.common.flogger.AbstractLogger;
import com.google.common.flogger.LogSite;
import com.google.common.flogger.LogSites;
import com.google.common.flogger.backend.Platform.LogCallerFinder;
import com.google.common.flogger.util.CallerFinder;
/**
* Default caller finder implementation which should work on all recent Java releases.
*
* See class documentation in {@link LogCallerFinder} for important implementation restrictions.
*/
public final class StackBasedCallerFinder extends LogCallerFinder {
private static final LogCallerFinder INSTANCE = new StackBasedCallerFinder();
// Called during logging platform initialization; MUST NOT call any code that might log.
public static LogCallerFinder getInstance() {
return INSTANCE;
}
@Override
public String findLoggingClass(Class> loggerClass) {
// We can skip at most only 1 method from the analysis, the inferLoggingClass() method itself.
StackTraceElement caller = CallerFinder.findCallerOf(loggerClass, 1);
if (caller != null) {
// This might contain '$' for inner/nested classes, but that's okay.
return caller.getClassName();
}
throw new IllegalStateException("no caller found on the stack for: " + loggerClass.getName());
}
@Override
public LogSite findLogSite(Class loggerApi, int stackFramesToSkip) {
// Skip an additional stack frame because we create the Throwable inside this method, not at
// the point that this method was invoked (which allows completely alternate implementations
// to avoid even constructing the Throwable instance).
StackTraceElement caller = CallerFinder.findCallerOf(loggerApi, stackFramesToSkip + 1);
// Returns INVALID if "caller" is null (no caller found for given API class).
return LogSites.logSiteFrom(caller);
}
@Override
public String toString() {
return "Default stack-based caller finder";
}
private StackBasedCallerFinder() {}
}