Java tutorial
/** * 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 net.logstash.logback.marker; import java.io.IOException; import java.util.Map; import net.logstash.logback.argument.StructuredArgument; import net.logstash.logback.composite.loggingevent.ArgumentsJsonProvider; import net.logstash.logback.composite.loggingevent.LogstashMarkersJsonProvider; import org.apache.commons.lang.ObjectUtils; import org.slf4j.Marker; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.databind.ObjectMapper; /** * A {@link Marker} OR {@link StructuredArgument} that appends entries * from a {@link Map} into the logging event output. * <p> * * When writing to the JSON data (via {@link ArgumentsJsonProvider} or {@link LogstashMarkersJsonProvider}): * <ul> * <li>Keys are converted to a {@link String} via {@link String#valueOf(Object)}, and used as field names.</li> * <li>Values are converted using an {@link ObjectMapper}.</li> * </ul> * <p> * * When writing to a String (when used as a {@link StructuredArgument} to the event's formatted message), * {@link String#valueOf(Object)} is used to convert the map to a string. * <p> * * For example, if the message is "mymessage {}", and map argument contains is * * <pre> * {@code * name1= a String "value1", * name2= an Integer 5, * name3= an array containing [1, 2, 3], * name4= a map containing name5=6 * } * </pre> * <p> * Then the message, name1, name2, name3, name4 fields will be added to the json for the logstash event. * <p> * For example: * * <pre> * { * "message" : "mymessage [name1=value1,name2=5,name3=[b...,name4=[name5=6]]", * "name1" : "value1", * "name2" : 5, * "name3" : [1, 2, 3], * "name4" : { "name5" : 6 } * } * <p> * * </pre> */ @SuppressWarnings("serial") public class MapEntriesAppendingMarker extends LogstashMarker implements StructuredArgument { public static final String MARKER_NAME = LogstashMarker.MARKER_NAME_PREFIX + "MAP_FIELDS"; /** * The map from which entries will be appended to the logstash json event. */ private final Map<?, ?> map; public MapEntriesAppendingMarker(Map<?, ?> map) { super(MARKER_NAME); this.map = map; } @Override public void writeTo(JsonGenerator generator) throws IOException { if (map != null) { for (Map.Entry<?, ?> entry : map.entrySet()) { generator.writeFieldName(String.valueOf(entry.getKey())); generator.writeObject(entry.getValue()); } } } @Override public String toString() { return String.valueOf(map); } @Override public boolean equals(Object obj) { if (!super.equals(obj)) { return false; } if (!(obj instanceof MapEntriesAppendingMarker)) { return false; } MapEntriesAppendingMarker other = (MapEntriesAppendingMarker) obj; return ObjectUtils.equals(this.map, other.map); } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + super.hashCode(); result = prime * result + (this.map == null ? 0 : this.map.hashCode()); return result; } }