| /** |
| * 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.s4.base; |
| |
| import java.util.Map; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.collect.Maps; |
| import com.google.common.primitives.Primitives; |
| |
| /** |
| * The base event class in S4. The base class supports generic key/value pairs which us useful for rapid prototyping and |
| * for inter-application communication. For greater efficiency and type safety, extend this class to create custom event |
| * types. |
| * |
| * |
| */ |
| public class Event { |
| |
| private static final Logger logger = LoggerFactory.getLogger(Event.class); |
| |
| final private long time; |
| private String streamId; |
| private Map<String, Data<?>> map; |
| |
| /** Default constructor sets time using system time. */ |
| public Event() { |
| this.time = System.currentTimeMillis(); |
| } |
| |
| /** |
| * This constructor explicitly sets the time. Event that need to explicitly set the time must call {super(time)} |
| */ |
| public Event(long time) { |
| this.time = time; |
| } |
| |
| /** |
| * @return the create time |
| */ |
| public long getTime() { |
| return time; |
| } |
| |
| /** |
| * The stream id is used to identify streams uniquely in a cluster configuration. It is not required to operate in |
| * local mode. |
| * |
| * @return the target stream id |
| */ |
| public String getStreamId() { |
| return streamId; |
| } |
| |
| /** |
| * |
| * @param streamName |
| * used to identify streams uniquely in a cluster configuration. It is not required to operate in local |
| * mode. |
| */ |
| public void setStreamId(String streamName) { |
| this.streamId = streamName; |
| } |
| |
| /** |
| * Put an arbitrary key-value pair in the event. The type of the value is T. |
| * |
| * @param type |
| * the type of the value |
| * @param key |
| * the key |
| * @param value |
| * the value |
| */ |
| public <T> void put(String key, Class<T> type, T value) { |
| |
| if (map == null) { |
| map = Maps.newHashMap(); |
| } |
| |
| map.put(key, new Data<T>(type, value)); |
| } |
| |
| /** |
| * Get value for key. The caller must know the type of the value. |
| * |
| * @param key |
| * @return the value |
| */ |
| @SuppressWarnings("unchecked") |
| public <T> T get(String key, Class<T> type) { |
| |
| Data<?> data = map.get(key); |
| |
| try { |
| return (T) data.value; |
| } catch (ClassCastException e) { |
| if (!Primitives.wrap(type).isAssignableFrom(Primitives.wrap(data.type))) { |
| logger.error("Trying to get a value of type {} for an attribute of type {}.", type, data.type); |
| return null; |
| } |
| throw e; |
| } |
| } |
| |
| /** |
| * Returns the value for key as a String. |
| * |
| * @param key |
| * @return the value as a string. |
| */ |
| public String get(String key) { |
| |
| Data<?> data = map.get(key); |
| |
| return String.valueOf(data.value); |
| } |
| |
| public boolean hasAttributes() { |
| |
| return map != null; |
| } |
| |
| public boolean containsKey(String key) { |
| return map.containsKey(key); |
| } |
| |
| public Map<String, String> getAttributesAsMap() { |
| |
| Map<String, String> amap = Maps.newHashMap(); |
| |
| for (Map.Entry<String, Data<?>> entry : map.entrySet()) { |
| String key = entry.getKey(); |
| String value = String.valueOf(entry.getValue().value); |
| amap.put(key, value); |
| } |
| return amap; |
| } |
| |
| /* Helper data object. */ |
| private static class Data<T> { |
| |
| Data() { |
| } |
| |
| private T value; |
| private Class<T> type; |
| |
| private Data(Class<T> type, T value) { |
| this.value = value; |
| this.type = type; |
| } |
| |
| } |
| |
| @Override |
| public String toString() { |
| Map<String, String> attributesAsMap = getAttributesAsMap(); |
| StringBuilder sb = new StringBuilder(); |
| sb.append("["); |
| for (Map.Entry<String, String> entry : attributesAsMap.entrySet()) { |
| sb.append("{" + entry.getKey() + ";" + entry.getValue() + "},"); |
| } |
| sb.append("]"); |
| return sb.toString(); |
| } |
| } |