org.apache.logging.log4j.util.SystemPropertiesPropertySource 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.Collection;
import java.util.Objects;
import java.util.Properties;
import aQute.bnd.annotation.Resolution;
import aQute.bnd.annotation.spi.ServiceProvider;
/**
* PropertySource backed by the current system properties. Other than having a
* higher priority over normal properties, this follows the same rules as
* {@link PropertiesPropertySource}.
*
* @since 2.10.0
*/
@ServiceProvider(value = PropertySource.class, resolution = Resolution.OPTIONAL)
public class SystemPropertiesPropertySource implements PropertySource {
private static final int DEFAULT_PRIORITY = 0;
private static final String PREFIX = "log4j2.";
/**
* Used by bootstrap code to get system properties without loading PropertiesUtil.
*/
public static String getSystemProperty(final String key, final String defaultValue) {
try {
return System.getProperty(key, defaultValue);
} catch (SecurityException e) {
// Silently ignore the exception
return defaultValue;
}
}
@Override
public int getPriority() {
return DEFAULT_PRIORITY;
}
@Override
public void forEach(final BiConsumer action) {
Properties properties;
try {
properties = System.getProperties();
} catch (final SecurityException e) {
// (1) There is no status logger.
// (2) LowLevelLogUtil also consults system properties ("line.separator") to
// open a BufferedWriter, so this may fail as well. Just having a hard reference
// in this code to LowLevelLogUtil would cause a problem.
// (3) We could log to System.err (nah) or just be quiet as we do now.
return;
}
// Lock properties only long enough to get a thread-safe SAFE snapshot of its
// current keys, an array.
final Object[] keySet;
synchronized (properties) {
keySet = properties.keySet().toArray();
}
// Then traverse for an unknown amount of time.
// Some keys may now be absent, in which case, the value is null.
for (final Object key : keySet) {
final String keyStr = Objects.toString(key, null);
action.accept(keyStr, properties.getProperty(keyStr));
}
}
@Override
public CharSequence getNormalForm(final Iterable tokens) {
return PREFIX + Util.joinAsCamelCase(tokens);
}
@Override
public Collection getPropertyNames() {
try {
return System.getProperties().stringPropertyNames();
} catch (final SecurityException e) {
return PropertySource.super.getPropertyNames();
}
}
@Override
public String getProperty(final String key) {
try {
return System.getProperty(key);
} catch (final SecurityException e) {
return PropertySource.super.getProperty(key);
}
}
@Override
public boolean containsProperty(final String key) {
return getProperty(key) != null;
}
}