com.google.common.util.concurrent.LazyLogger Maven / Gradle / Ivy
Go to download
This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright (C) 2023 The Guava 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.util.concurrent;
import com.google.common.annotations.GwtCompatible;
import java.util.logging.Logger;
import org.checkerframework.checker.nullness.qual.Nullable;
/** A holder for a {@link Logger} that is initialized only when requested. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class LazyLogger {
private final String loggerName;
private volatile @Nullable Logger logger;
LazyLogger(Class ownerOfLogger) {
this.loggerName = ownerOfLogger.getName();
}
Logger get() {
/*
* We use double-checked locking. We could the try racy single-check idiom, but that would
* depend on Logger not contain mutable state.
*
* We could use Suppliers.memoizingSupplier here, but I micro-optimized to this implementation
* to avoid the extra class for the lambda (and maybe more for memoizingSupplier itself) and the
* indirection.
*
* One thing to *avoid* is a change to make each Logger user use memoizingSupplier directly:
* That may introduce an extra class for each lambda (currently a dozen).
*/
Logger local = logger;
if (local != null) {
return local;
}
synchronized (this) {
local = logger;
if (local != null) {
return local;
}
return logger = Logger.getLogger(loggerName);
}
}
}