Java tutorial
/* * Copyright 2016 Cask Data, Inc. * * 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 co.cask.cdap.logging.gateway.handlers; import ch.qos.logback.classic.spi.ILoggingEvent; import ch.qos.logback.classic.spi.ThrowableProxyUtil; import co.cask.cdap.logging.read.LogEvent; import co.cask.http.HttpResponder; import com.google.gson.JsonElement; import com.google.gson.JsonObject; import java.util.List; /** * LogReader callback to encode log events, as {@link LogData} objects. */ public class LogDataOffsetCallback extends AbstractJSONCallback { private final List<String> fieldsToSuppress; LogDataOffsetCallback(HttpResponder responder, List<String> fieldsToSuppress) { super(responder); this.fieldsToSuppress = fieldsToSuppress; validate(); } @Override public Object encodeSend(LogEvent logEvent) { ILoggingEvent event = logEvent.getLoggingEvent(); StackTraceElement[] stackTraceElements = event.getCallerData(); String className = ""; String simpleClassName = ""; int lineNumber = 0; if (stackTraceElements != null && stackTraceElements.length > 0) { StackTraceElement first = stackTraceElements[0]; className = first.getClassName(); simpleClassName = (className.indexOf('.') >= 0) ? className.substring(className.lastIndexOf('.') + 1) : className; lineNumber = first.getLineNumber(); } LogData logData = new LogData(event.getTimeStamp(), event.getLevel().toString(), event.getThreadName(), className, simpleClassName, lineNumber, event.getFormattedMessage(), ThrowableProxyUtil.asString(event.getThrowableProxy())); return modifyLogJsonElememnt(GSON.toJsonTree(new FormattedLogDataEvent(logData, logEvent.getOffset()))); } private Object modifyLogJsonElememnt(JsonElement jsonElement) { JsonObject jsonLogData = (JsonObject) jsonElement; JsonObject logData = jsonLogData.getAsJsonObject("log"); if (!fieldsToSuppress.isEmpty()) { for (String field : fieldsToSuppress) { logData.remove(field); } } return jsonLogData; } private void validate() { if (fieldsToSuppress.isEmpty()) { return; } for (String fieldToSuppress : fieldsToSuppress) { try { LogData.class.getDeclaredField(fieldToSuppress); } catch (NoSuchFieldException e) { throw new IllegalArgumentException( String.format("Field %s is not supported as suppress field", fieldToSuppress)); } } } }