001/* 002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. All Rights Reserved. 003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved. 004 * 005 * Project and contact information: http://www.cascading.org/ 006 * 007 * This file is part of the Cascading project. 008 * 009 * Licensed under the Apache License, Version 2.0 (the "License"); 010 * you may not use this file except in compliance with the License. 011 * You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, software 016 * distributed under the License is distributed on an "AS IS" BASIS, 017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 018 * See the License for the specific language governing permissions and 019 * limitations under the License. 020 */ 021 022package cascading.management.annotation; 023 024import java.lang.annotation.ElementType; 025import java.lang.annotation.Retention; 026import java.lang.annotation.RetentionPolicy; 027import java.lang.annotation.Target; 028 029/** 030 * Property annotations can be used to send additional information about certain aspects of Cascading classes 031 * to the {@link cascading.management.DocumentService}. The properties are present at runtime and allow a 032 * DocumentService to inspect, process or persist them. 033 * <p> 034 * Property annotations can be applied to {@link cascading.tap.Tap}s, {@link cascading.scheme.Scheme}s, 035 * and any {@link cascading.operation.Operation} sub-classes (like Function or Aggregator). 036 * <p> 037 * Property annotations can be applied to any method or field members, so that they can be accessed via 038 * java.lang.Class#getMethods() and java.lang.Class.getFields() respectively. If the member is protected/private, 039 * there will be an attempt to bypass the protected/private scope to retrieve the value. 040 * <p> 041 * By default the {@link Visibility} is {@link Visibility#PUBLIC}, and optionality is {@code true}. 042 */ 043@Retention(RetentionPolicy.RUNTIME) 044@Target({ElementType.METHOD, ElementType.FIELD}) 045public @interface Property 046 { 047 /** 048 * The display name for the property value. Does not need to match the bean property or field name. 049 * 050 * @return the display name 051 */ 052 String name(); 053 054 /** 055 * The display visibility, see {@link Visibility}. 056 * 057 * @return the display visibility 058 */ 059 Visibility visibility() default Visibility.PUBLIC; 060 061 /** 062 * Whether the field name and null should be displayed if the value is {@code null}. 063 * <p> 064 * When {@code true}, no data (field name, visibility, and the {@code null} value are sent to the display. The property 065 * is ignored. 066 * 067 * @return whether the field should be displayed if {@code null} 068 */ 069 boolean optional() default true; 070 }