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