| /** |
| * 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.List; |
| |
| import org.apache.commons.lang.StringUtils; |
| |
| /** |
| * The Key class is used to get the value of the key on a specific type of event. This is done to abstract all the |
| * complexity required to get the value. The method for getting the value is implemented in a method of an object of |
| * type KeyFinder<T>. |
| * <p> |
| * The application programmer provides the events and the corresponding finders. The framework will use it to key on |
| * events. |
| */ |
| public class Key<T extends Event> { |
| |
| final private KeyFinder<T> finder; |
| final private String separator; |
| |
| public Key(KeyFinder<T> finder, String separator) { |
| this.finder = finder; |
| this.separator = separator; |
| } |
| |
| public List<String> getList(T event) { |
| return finder.get(event); |
| } |
| |
| public String get(T event) { |
| List<String> keys = getList(event); |
| |
| return StringUtils.join(keys, separator); |
| } |
| } |