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Apache Log4j Layout for JSON template.
/*
* 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.layout.template.json.resolver;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.layout.template.json.JsonTemplateLayout;
import org.apache.logging.log4j.layout.template.json.util.JsonWriter;
/**
* Resolver for the {@link StackTraceElement} returned by {@link LogEvent#getSource()}.
*
* Note that this resolver is toggled by {@link
* JsonTemplateLayout.Builder#setLocationInfoEnabled(boolean) locationInfoEnabled}
* layout configuration, which is by default populated from {@code log4j.layout.jsonTemplate.locationInfoEnabled}
* system property.
*
*
Configuration
*
*
* config = "field" -> (
* "className" |
* "fileName" |
* "methodName" |
* "lineNumber" )
*
*
* Examples
*
* Resolve the line number:
*
*
* {
* "$resolver": "source",
* "field": "lineNumber"
* }
*
*/
public final class SourceResolver implements EventResolver {
private static final EventResolver NULL_RESOLVER =
(final LogEvent value, final JsonWriter jsonWriter) ->
jsonWriter.writeNull();
private static final EventResolver CLASS_NAME_RESOLVER =
(final LogEvent logEvent, final JsonWriter jsonWriter) -> {
final StackTraceElement logEventSource = logEvent.getSource();
if (logEventSource == null) {
jsonWriter.writeNull();
} else {
final String sourceClassName = logEventSource.getClassName();
jsonWriter.writeString(sourceClassName);
}
};
private static final EventResolver FILE_NAME_RESOLVER =
(final LogEvent logEvent, final JsonWriter jsonWriter) -> {
final StackTraceElement logEventSource = logEvent.getSource();
if (logEventSource == null) {
jsonWriter.writeNull();
} else {
final String sourceFileName = logEventSource.getFileName();
jsonWriter.writeString(sourceFileName);
}
};
private static final EventResolver LINE_NUMBER_RESOLVER =
(final LogEvent logEvent, final JsonWriter jsonWriter) -> {
final StackTraceElement logEventSource = logEvent.getSource();
if (logEventSource == null) {
jsonWriter.writeNull();
} else {
final int sourceLineNumber = logEventSource.getLineNumber();
jsonWriter.writeNumber(sourceLineNumber);
}
};
private static final EventResolver METHOD_NAME_RESOLVER =
(final LogEvent logEvent, final JsonWriter jsonWriter) -> {
final StackTraceElement logEventSource = logEvent.getSource();
if (logEventSource == null) {
jsonWriter.writeNull();
} else {
final String sourceMethodName = logEventSource.getMethodName();
jsonWriter.writeString(sourceMethodName);
}
};
private final boolean locationInfoEnabled;
private final EventResolver internalResolver;
SourceResolver(
final EventResolverContext context,
final TemplateResolverConfig config) {
this.locationInfoEnabled = context.isLocationInfoEnabled();
this.internalResolver = createInternalResolver(context, config);
}
private static EventResolver createInternalResolver(
final EventResolverContext context,
final TemplateResolverConfig config) {
if (!context.isLocationInfoEnabled()) {
return NULL_RESOLVER;
}
final String fieldName = config.getString("field");
if ("className".equals(fieldName)) {
return CLASS_NAME_RESOLVER;
} else if ("fileName".equals(fieldName)) {
return FILE_NAME_RESOLVER;
} else if ("lineNumber".equals(fieldName)) {
return LINE_NUMBER_RESOLVER;
} else if ("methodName".equals(fieldName)) {
return METHOD_NAME_RESOLVER;
}
throw new IllegalArgumentException("unknown field: " + config);
}
static String getName() {
return "source";
}
@Override
public boolean isResolvable() {
return locationInfoEnabled;
}
@Override
public boolean isResolvable(final LogEvent logEvent) {
return locationInfoEnabled && logEvent.getSource() != null;
}
@Override
public void resolve(
final LogEvent logEvent,
final JsonWriter jsonWriter) {
internalResolver.resolve(logEvent, jsonWriter);
}
}